Next Article in Journal
In Vitro Anti-Inflammatory Activity of Methyl Derivatives of Flavanone
Next Article in Special Issue
Fluorescent Paper Based on CQDs/Rhodamine B: A Ratio and Sensitive Detection Platform for On-Site Fe3+ Sensing
Previous Article in Journal
Identification of Aggregation Processes in Hexamethylenetetramine Aqueous Solutions: A Comprehensive Raman and Acoustic Spectroscopic Study Combined with Density Functional Theory Calculations
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Molecules
Volume 28
Issue 23
10.3390/molecules28237839
molecules-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles thumb_up
...
Endorse textsms
...
Comment
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Cationic Surfactant-Modified Tetraselmis sp. for the Removal of Organic Dyes from Aqueous Solution

by
Buhani
1,
Istikomah
1,
Suharso
1,
Sumadi
2,
Sutarto
3,
Huda M. Alghamdi
4 and
Khalid Z. Elwakeel
4,5,*
1
Department of Chemistry, Faculty of Mathematic and Natural Sciences, University of Lampung, Jl. Soemantri Brojonegoro No. 1, Bandar Lampung 35145, Indonesia
2
Department of Electrical Engineering, Faculty of Engineering, University of Lampung, Jl. Soemantri Brojonegoro No. 1, Bandar Lampung 35145, Indonesia
3
Department of Medicine, Faculty of Medicine, University of Lampung, Bandar Lampung 35141, Indonesia
4
Department of Chemistry, College of Science, University of Jeddah, Jeddah 80327, Saudi Arabia
5
Environmental Chemistry Division, Environmental Science Department, Faculty of Science, Port Said University, Port Said 42522, Egypt
*
Author to whom correspondence should be addressed.
Molecules 2023, 28(23), 7839; https://doi.org/10.3390/molecules28237839
Submission received: 6 November 2023 / Revised: 15 November 2023 / Accepted: 20 November 2023 / Published: 29 November 2023
(This article belongs to the Special Issue Biomass-Derived Materials for Environmental Applications)
Browse Figures
Review Reports Versions Notes

Abstract

:
The modification of the Tetraselmis sp. algae material (Tetra-Alg) with surfactant Cethyltrimethylammonium Bromide (CTAB) yielded adsorbent Tetra-Alg-CTAB as an adsorbent of methyl orange (MO) and methylene blue (MB) solutions. The characterization of the adsorbent used an infrared (IR) spectrometer to identify functional groups and Scanning Electron Microscopy with Energy Dispersive X-ray (SEM-EDX FEI Inspect-S50, Midland, ON, Canada) to determine the surface morphology and elemental composition. Methyl orange and methylene blue adsorption on the adsorbent Tetra-Alg, Tetraselmis sp. algae-modified Na+ ions (Tetra-Alg-Na), and Tetra-Alg-CTAB were studied, including variations in pH, contact time, concentration, and reuse of adsorbents. The adsorption of MO and MB by Tetra-Alg-CTAB at pH 10, during a contact time of 90 min, and at a concentration of 250 mg L−1 resulted in MO and MB being absorbed in the amounts of 128.369 and 51.013 mg g−1, respectively. The adsorption kinetics and adsorption isotherms of MO and MB and Tetra-Alg, Tetra-Alg-Na, and Tetra-Alg-CTAB tend to follow pseudo-second-order kinetics models and Freundlich adsorption isotherms with each correlation coefficient value (R2) approaching 1. Due to the modification with the cationic surfactant CTAB, anionic dyes can be strongly sorbed in alkaline pH due to strong electrostatic attraction, while MB is more likely to involve cation exchange and hydrogen bonding. The reuse of Tetra-Alg-CTAB was carried out four times with adsorption percent > 70%, and the adsorbent was very effective in the adsorption of anionic dyes such as MO.

1. Introduction

Aquatic environmental problems, such as water that is not fit for consumption, have become very common nowadays. The problem is triggered by pollution originating from the accumulation of various kinds of waste. One sector that contributes to waste in the aquatic environment is the textile industry sector. Although the textile industry is one of the sectors that has a positive impact on supporting economic development, the textile industry also contributes a very detrimental negative impact to the environment due to the presence of waste products in the form of dye waste. This is supported by data; it is estimated that the textile industry consumes about 60% of the total dye produced, and about 10–15% of the remaining dye comes out as waste [1,2]. When the waste is discharged into the aquatic environment, the textile dyes contained in the waste will become more stable and more difficult to decompose due to the complex chemical structure formed [3].
Dye waste that enters water forms a more complex chemical structure, causing the dye to be difficult to decompose in water [4]. Types of synthetic dyes that are widely produced and used in the textile industry are thiazine dyes, such as methylene blue, and compounds with an azo group, such as methyl orange. Thiazine compounds have functional group characteristics, namely the presence of a group (C=N), and if there is an increase in the amount of thiazine dye in the water, it will reduce the level of dissolved oxygen in the water and damage aquatic life [5,6]. Methyl orange is one of the anionic dyestuffs with an azo group and its derivatives from the benzene group [7]. Azo compounds are compounds that have an N=N group, called the azo structure, and are most commonly found in waste. Because of their widespread usage, toxicity, carcinogenicity, and poor removal rates during wastewater treatment, most of these synthetic dyes pose a threat to the environment [8,9,10,11]. Additionally, when the amount of oxygen in the water drops, anaerobic organisms become more active, producing a product with an unpleasant odor [12].
Treating garbage that contains dyes before it is released into the environment is one of the best strategies to lower pollution and the spread of dyes in the environment. Synthetic dyes have been eliminated from industrial effluents using a variety of physical and chemical techniques, including adsorption, flocculation, coagulation, membrane filtration, photocatalytic degradation, and irradiation [13,14,15,16]. Of these several methods, the adsorption method is quite widely used. The adsorption process is easy to use, reasonably priced, and produces no environmentally hazardous byproducts [17,18]. The kind and compatibility of the adsorbent utilized have a major impact on the adsorption process’s outcome. A high adsorption rate and capacity are necessary for an efficient adsorbent in adsorption. It can also be utilized repeatedly, is environmentally friendly, and is chemically stable [19,20].
Currently, adsorption is being widely developed to reduce the contamination of synthetic dyes in liquid waste by using adsorbent base materials derived from organisms such as fungi, bacteria, yeast, and algal biomass [21,22,23]. Algal biomass is generally used as an adsorbent because it can be available in large quantities. In addition, it is an effective and relatively inexpensive adsorbent [20,24].
By nature, algal biomass is a highly potent adsorbent that can remove contaminants from organic substances, including dye-derived chemicals [19,22,25]. Nevertheless, several limitations, including their tiny size, low specific gravity, and susceptibility to degradation by other microbes, limit their capacity to bind these chemical substances [26,27]. Numerous attempts have been made to address these shortcomings, including improving the biomass of the algae using different modifying agents [20,21,28].
The capacity and quality of algal biomass can be increased by using adsorbent surface modifying agents such as cationic surfactant CTAB. Surface modification of algal biomass with cationic surfactants can make the adsorbent rich in positive charges so that it will be effective against adsorbates that tend to be negatively charged [29,30,31]. An adsorbent has an alkaline or alkaline earth cation exchange active group that can be swapped out for various cations, including cationic surfactants, to serve as a charge balancer [32,33,34].
A good sorbent, especially for large-scale applications, must be recyclable in order to be competitive. Both the demand for fresh sorbent and the issue of disposing of spent sorbent can be addressed via regeneration. Different regeneration techniques have been applied, with varying degrees of effectiveness. Solvent-washing, thermal, chemical, and electrochemical regeneration are some of these techniques [35]. Recently, upcycling of dye-loaded spent sorbent via an appropriate management pathway (anaerobic fermentation) for the development of a low-cost hydrogen production scenario was investigated [36]; the findings of that study inferred that the spent algal sorbent could be introduced as an effective substitute for biohydrogen production.
Based on this description, an adsorbent was created in this study using the cation exchange characteristics of CTAB surfactants and the active groups of algal biomasses to adsorb MO and MB dyes. The algal biomass of Tetraselmis sp. was modified for this purpose. Consequently, it is possible to produce an efficient adsorbent to adsorb colors in solution. Dye desorption and sorbent recycling are carried out after sorption kinetic and equilibrium investigations. The findings of this study may offer a way to stop dangerous dyes from spreading across the environment.

2. Results and Discussion

2.1. Adsorbent Characterization

Analysis of Tetra-Alg, Tetra-Alg-Na, and Tetra-Alg-CTAB (Figure 1) using an IR spectrometer showed that, on the three adsorbents, there was an absorption band at a wave number of 3695.61 cm−1 which indicated the presence of N-H stretching vibrations. In addition, at a wave number around 3425.58 cm−1, there is an absorption band indicating the presence of O-H stretching vibrations, and at 2931.80 cm−1 one from the C-H (alkyl) stretching vibration of aliphatic (-CH2) and the carbonyl group (C=O) at number waves around 1651.07 cm−1. The success of Tetra-Alg modification with CTAB is indicated by the appearance of an absorption band at wave number 1465.90 cm−1 originating from the methyl group contained in CTAB in Tetra-Alg-CTAB (Figure 1c), while in Tetra-Alg and Tetra-Alg-Na the absorption band does not appear.
Surface morphology and elemental constituents of Tetra-Alg, Tetra-Alg-Na, Tetra-Alg-CTAB were studied using SEM-EDX. The results of the analysis using SEM-EDX (Figure 2) showed that there were differences in morphology between Tetra-Alg, Tetra-Alg-Na, and Tetra-Alg-CTAB. In Figure 2a, Tetra-Alg morphology looks less contrasting and there are homogeneous grains, while Tetra-Alg-Na (Figure 2b) shows a less homogeneous morphology with more contrasting colors. The contrasting color difference comes from the presence of the metallic element of Na. Furthermore, in Tetra-Alg-CTAB) there are grains attached to the surface, which are homogeneous with less contrasting colors. This shows that the modification of Tetra-Alg with CTAB causes CTAB not to be absorbed in Tetra-Alg, but only to cover the algal cell wall [20,37].
The results of the analysis with surface morphology are supported by the results of the analysis with EDX. Based on EDX data on Tetra-Alg (Figure 2a), there are the elements C, N, and O derived from organic groups from algal biomass while in Tetra-Alg-Na, apart from the elements found in Tetra-Alg, other elements appear, that is, Na derived from NaCl. Furthermore, the EDX data on Algae-CTAB (Figure 2c) contained the elements of C, N, O, and Br. The presence of Br in Tetra-Alg-CTAB indicates that modification of CTAB surfactant on Tetra-Alg has been successfully carried out [37].
The surface area of the resin was calculated using the following Equation [38]:
A s = 10 − 20 M   M W   G   N A V ϕ
where A s is the adsorbent surface area in m2 g−1, G the amount of methylene blue adsorbed (g) based on Langmuir adsorption capacity, NAv the Avogadro number (6.02 × 1023), ϕ the methylene blue molecular cross-section (197.2 Å), MW the molecular weight of methylene blue (373.9 g mol−1) and M the mass of adsorbent (g). The surface area of Tetra-Alg, Tetra-Alg-Na, and Tetra-Alg-CTAB was found to be 158.93, 184.64, and 161.97 m2 g−1, respectively.

2.2. pHpzc of Adsorbent

Determination of the pHpzc value was carried out to study the effect of pH on the surface charge of Tetra-Alg, Tetra-Alg-Na, Tetra-Alg-CTAB. In Figure 3, it can be observed that the pHpzc value of the three adsorbents is at pH 8. The pH area below pHpzc is positively charged, while the pH area above pHpzc is negatively charged [19,39].

2.3. Effect of Adsorption Initial pH

Because pH changes the dissolved adsorbate speciation and the active surface charge of the adsorbent, it has a major effect on the adsorption process. In Figure 4, the relationship between initial pH (pH0) and % of adsorbed dye can be observed. The effect of interaction pH0 on % MO adsorbed (Figure 4) showed that % MO adsorbed at interaction pH 10 by Tetra-Alg-CTAB was the largest (99.32%) compared to Tetra-Alg (5.86%) and Tetra-Alg-Na (5.11%). This happens because of the modification with CTAB to obtain an adsorbent that is rich in positively charged active sites. Based on the pHpzc value (Figure 3), it can be stated that at pH 10 the adsorbent has a positive surface charge so that it can properly adsorb the anionic (negative) MO dye through electrostatic interactions, causing high adsorption [29,37].
In Figure 4, it can also be seen that the % MB adsorbed by Tetra-Alg and Tetra-Alg-Na in all pH ranges is almost the same. In Tetra-Alg-CTAB, the % MB adsorbed was relatively lower than Tetra-Alg and Tetra-Alg-Na. This happens because Tetra-Alg-CTAB is dominated by positive charge, so it is less effective in interacting with cationic MB. Therefore, the increase in MO removal after cationic surfactant modification can be explained by electrostatic interactions. Even at pH0 values = 3, the adsorption of MO remained significantly high due to the presence of the cationic surfactant, while MB adsorption is more likely to involve cation exchange and hydrogen bonding. The adsorption process mechanism may also be significantly influenced by other forces such as n–π stacking interactions and dipole-dipole hydrogen bonding [40]. It is also important to remember that some oppositely charged surface sites may have existed concurrently with the overall negatively or positively charged adsorbent surface charge. Also, in Figure 4, it can be observed that the highest adsorption occurred at pH 12 for Tetra-Alg, Tetra-Alg-Na, Tetra-Alg-CTAB with % MB adsorbed, respectively, being 97.41, 98.35, and 99.11%. However, at pH 12 there was high adsorption of MB by the three adsorbents; it is assumed that the interaction that occurs between the adsorbent and MB is a precipitation process caused by the high concentration of OH- in the solution under alkaline conditions [21].

2.4. Effect of Contact Time

The relationship between adsorption contact time on % MO and MB adsorbed by Tetra-Alg, Tetra-Alg-Na, Tetra-Alg-CTAB is shown in Figure 5. In Figure 5, it can be seen that the addition of relative adsorption interaction time did not increase the % MO and MB adsorbed. At the interaction time of 90 min, it was observed that the % MO adsorbed on Tetra-Alg, Tetra-Alg-Na, and Tetra-Alg-CTAB was 12.86, 14.97, and 99.17%, respectively. Then, at the same time, the contact time of 90 min, the % MB adsorbed by Tetra-Alg, Tetra-Alg-Na, and Tetra-Alg-CTAB was 93.38, 96.58, and 61.94%, respectively.
In Figure 5, it can be observed that, when the two data of MO and MB dyes are compared, MO dyes are more adsorbed on Tetra-Alg-CTAB while MB tends to be adsorbed by Tetra-Alg and Tetra-Alg-Na. This is in line with the data obtained on the effect of pH interactions (Figure 4). The interaction of MO with Tetra-Alg-CTAB occurs through electrostatic interactions because the adsorbent Tetra-Alg-CTAB is rich in positively charged active sites while MO is anionic [30,31].

2.5. Adsorption Kinetics

By utilizing the pseudo-second-order (PSO) kinetic model (Equation (2)) and the intra-particle diffusion (IPD) Model (Equation (3)), the adsorption kinetics parameters of MO and MB dyes were ascertained through an analysis of the data presented in Figure 5. The pseudo-second-order kinetic model assumes that the adsorption capacity is proportional to the number of active sites on the adsorbent. By applying the linear Equation (2),
t q t = 1 k 2 q e 2 + t q e
where qt and qe (mg g−1) are total MO or MB adsorption capacity at time t and equilibrium, respectively, and k2 is the second-order rate constant, respectively, the results of the analysis of the adsorption kinetics data were obtained and are presented in Table 1.
From Table 1, it can be seen that each value of the linear correlation coefficient (R2) of the second-order model of the MO and MB dyes by Tetra-Alg, Tetra-Alg-Na, Tetra-Alg-CTAB is relatively the same. If the k2 values of both MO and MB dyes are compared, it can be seen that the MO adsorption rate is greater than MB. Furthermore, the adsorption rate of MO-dye on Tetra-Alg-CTAB is higher than that of Tetra-Alg and Tetra-Alg-Na.
Data on the effect of contact time (Figure 5) were also analyzed using the intra-particle diffusion (IPD) kinetic model developed by Morris and Weber [41,42]. The IPD kinetic model assumes that the diffusion process of an adsorbate, such as dye, to an adsorbent is controlled by a physical mechanism that has an important role in the adsorption process, as described by Equation (3).
q t = k i d t 0.5 + C
The intra-particle diffusion rate constant is denoted by kid (mg g−1 min−0.5), whereas the constant C value (mg g−1) indicates the barrier to mass transfer in the boundary layer. The slope and intercept of the lines derived from plots of qt versus t0.5 were used to compute the values of kid and C. The results of the analysis of MO and MB adsorption data by Tetra-Alg, Tetra-Alg-Na, and Tetra-Alg-CTAB obtained from the completion of the IPD kinetic model are shown in Table 2 and Figure 6.
It is evident from Figure 6 that every plot has two linear components. This pattern suggests the involvement of many adsorption models. The external mass transfer is shown by the pattern in the first linear portion, which spans an adsorption time of 0 to 60 min. The second linear section covers an adsorption period of 60–120 min, representing the pattern describing the intraparticle diffusion of the particles. The fact that the second linear portion does not pass through the origin (C ≠ 0) shows that intraparticle diffusion controls the rate of external mass transfer simultaneously with other steps [41,42].
Based on the observations in Figure 6, two steps describe the transfer of the dye from the solution to the external surface of the adsorbent and directed diffusion. Then, the step is continued from the dye to the active site of each adsorbent through the pore cavity and the active group. The adsorption mechanism can be explained in two different ways, namely the occurrence of diffusion through the pores of the adsorbent and electrostatic interactions in the presence of a positively charged functional group from the modification of Tetra-Alg to Tetra-Alg-CTAB [43]. This is in line with the results of the second-order pseudo-kinetic model analysis that has been discussed previously.

2.6. Adsorption Isotherm

The MO and MB adsorption isotherm models were studied by varying the dye concentration from 0–250 mg L−1, as shown in Figure 7. Based on the data in Figure 7, it can be observed that the adsorption of MO and MB by Tetra-Alg, Tetra-Alg-Na, and Tetra-Alg-CTAB increased with the increasing concentrations used. The data contained in Figure 7 were analyzed using the Freundlich (Equation (4)) and Langmuir (Equation (5)) isotherm models, as follows:
log q e = log K F + 1 n log C e
1 q e = 1 q m K L C e + 1 q m
where KF is the Freundlich constant related to adsorption capacity (mg g−1) (L mg−1)1/n) and n is the adsorption intensity. KL is the ratio of the adsorption and desorption rate in L mg−1, and qm is the maximum adsorption capacity estimated by the Langmuir model in mg g−1.
The Freundlich isotherm model is an empirical formula used to describe adsorption at multilayer and heterogeneous systems [44]. The Langmuir adsorption isotherm model assumes that the adsorbent surface is uniform, there are a fixed number of active sites proportionate to the surface area, and the adsorption process is monolayer [45,46]. The results of the data analysis in Figure 7 are shown in Table 3.
Based on the data obtained in Table 3, it can be observed that the adsorption on MO and MB tends to follow the Freundlich adsorption isotherm model. This can be seen from the coefficient value (R2) on the Freundlich adsorption isotherm, which is closer to 1 when compared to the correlation coefficient value (R2) on the Langmuir adsorption isotherm. The Freundlich adsorption isotherm model assumes that the dye layer formed on the surface of the adsorbent is a multilayer [47]. From Table 3, it can be observed that the adsorption capacity of MO that was adsorbed by Tetra-Alg-Na and Tetra-Alg-CTAB was greater than that of MB. This happens because the interaction that occurs between MO with Tetra-Alg-Na and Tetra-Alg-CTAB tends to occur through electrostatic interactions, while MB is more likely to involve cation exchange [32,33].
Table 4 presents a comparison between the adsorption capacities of Tetra-Alg-CTAB for the MO and MB dyes and those of previously documented adsorbents. The information in Table 4 illustrates that Tetra-Alg-CTAB exhibits remarkable effectiveness as an adsorbent for the MO dye, especially when contrasted with other adsorbents featured in the same table. The comparison of sorption performances for Tetra-Alg-CTAB and with other algal biomasses clearly demonstrates the synergistic effect of precursors. The incorporation of the cationic surfactant CTAB in the algal biomass allows for the improvement of the sorption of MO. The cationic surfactant-modified biosorbent exhibited a notable increase in its ability to attract anionic dye molecules. This is due to the introduction of positive charges on the Tetra-Alg-CTAB surface, which enhances the adsorption of MO via electrostatic interaction, while MB sorption is more likely to occur through cation exchange.

2.7. Adsorbent Reuse

The reuse of Tetra-Alg, Tetra-Alg-Na, and Tetra-Alg-CTAB adsorbents to adsorb MO solution in several cycles is an important parameter in determining the quality of the adsorbent produced. The adsorbent can be reused several times to obtain the best quality from the adsorbent and economic efficiency.
In Figure 8 it can be seen that the reuse of Tetra-Alg-CTAB to adsorb MO showed effective results of more than 70% on four successive repetition cycles, of 99.97, 91.97, 81.41, and 71.90%. The reuse of Tetra-Alg and Tetra-Alg-Na adsorbents is not very effective. This is in line with the low % MO-dye adsorbed in the first cycle and continues to decrease until the fifth cycle. The adsorption yield decreased significantly in each iteration cycle. The decrease in adsorption ability occurs due to the decrease in the active site on the adsorbent caused by the desorption process carried out to release the adsorbed methyl orange dye [55].

3. Materials and Methods

3.1. Materials and Instruments

The algal biomass of Tetraselmis sp. was obtained from cultivation at the Center for Marine Cultivation in Lampung, Indonesia and prepared into algal biomass in the Inorganic chemistry laboratory of the Faculty of Mathematics and Natural Sciences, University of Lampung. MO and MB dyes (Table S1) and other chemicals required for algal biomass modification and adsorption processes such as NaCl, NaNO3, CTAB, HCl, NaOH, citrate buffer, and phosphate buffer are analytical reagents (AR) grade and purchased from Pharmacopoeia European.
The characterization of the adsorbent was carried out with an IR spectrometer (Shimadzu IRPrestige-21, Shimadzu Corporation, Tokyo, Japan) to identify the functional groups of the adsorbent. Surface morphology analysis of the adsorbent was carried out using Scanning Electron Microscopy with Energy Dispersive X-ray (SEM-EDX FEI Inspect-S50, Midland, ON, Canada).

3.2. Adsorbent Preparation

The Tetra-Alg biomass was air-dried for 3 days and continued in the oven at 40 °C for 3 h, then ground using a grinder to form a fine powder with a size of 100 mesh. A total of 5 g of Tetra-Alg was added to 100 mL of 0.1 M NaCl in a 250 mL Erlenmeyer flask. The mixture was stirred using a shaker for 1 h, then allowed to stand for 24 h with the Erlenmeyer mouth closed. After being separated, the resulting precipitate was washed with distilled water until neutral. After that, the precipitate dried at room temperature until the weight was constant (Tetra-Alg-Na). Then, 2 g of Tetra-Alg-Na was mixed with 200 mL 14 mmol L−1 CTAB solution in an Erlenmeyer flask and put into a water bath at 50 °C under stirring. Then, the resulting precipitate was washed with distilled water until neutral and dried at room temperature to a constant weight to produce Tetra-Alg-CTAB.

3.3. Determination of pHpzc of Adsorbent

A total of 0.05 g of adsorbent was mixed with 10 mL of 0.1 M NaNO3 solution with a pH varying between 3 to 12. pH adjustment can be carried out by adding 0.1 M NaOH for alkaline conditions and 0.1 M HCl for acidic conditions. The solution was then stirred using a stirrer for 24 h. The supernatant was then poured, and the pH was measured. The pHpzc value was obtained from the plot of the pH of the initial solution against the pH of the supernatant [53].

3.4. Dye Adsorption Batch Experiments

MO and MB adsorption studies were carried out using the batch method. The adsorbates used were MO and MB dyes. Adsorbate mother liquor (1 g L−1) is prepared by dissolving a certain amount of adsorbate in distilled water. Then, the mother liquor is diluted to the desired concentration. The parameters studied include the determination of adsorption kinetics and isotherms. The standard curve between absorbance (A) and dye concentration (C0, mgL−1) was measured with a UV-Vis spectrophotometer (Agilent Cary 100, Markham, ON, Canada) at the maximum absorption wavelength of the dye (MO max = 465 nm; and MB max = 664 nm). MO or MB dyes were mixed with the adsorbent at a pH varying between 3–12, during a contact time between 0–90 min, and at a dye concentration varying from 0–250 mg L−1. Adsorption was carried out in a shaker incubator at a temperature of 25 °C at a speed of 200 rpm. The mixture between the filtrate and the precipitate was separated by centrifugation, and the filtrate was analyzed using a UV-Vis spectrophotometer. The level of MO or MB adsorbed by the adsorbent is determined by calculating the adsorbate adsorbed per unit mass of adsorbent, and the percentage of dye absorbed by the adsorbent is calculated using the following equations:
q e = ( C 0 − C e ) m × V
q t = ( C o − C t ) m × V
A d s o r p t i o n   ( % ) = ( C o − C t ) C o × 100
where Co is the initial dye concentration, Ce is the equilibrium concentration, Ct is the concentration at a certain time t of dye solution (mg L−1), m is the mass of adsorbent (g), V is the volume of the solution (L), q is the amount of dye adsorbed per unit mass (mmol g−1), and Adsorption (%) is the percentage of the dye removal. All adsorption tests were performed in triplicate, and the averages were recorded. The limit of experimental errors on triplicates was systematically below 5%.
Note: full experimental conditions are systematically reported in the caption of the figures and tables.
The same batch process was used for the investigation of dye desorption and adsorbent recycling. The dye-loaded Tetra-Alg-CTAB adsorbents (recovered from sorption equilibrium tests) were first washed to remove the absorbed dye. In a second step, the adsorbent was mixed with 0.5 M HCl + 0.5 M NaCl mixed solution (adsorbent dose: 5.0 g adsorbent per 100 mL eluent) for 140 min. The suspension was centrifuged; the supernatant was analyzed for residual dye concentration. The collected sorbent was repeatedly rinsed with distilled water until the pH of the rinsing water reached 7.0. The regenerated sorbent was dried for 2 h at 40 °C in an oven (Gallenkamp BS Model OV-160, Loughborough (LE), UK) and subjected to 5 consecutive adsorption/desorption cycles. The adsorption (%) was calculated according to Equation (1).

4. Conclusions

Production of an adsorbent from algal biomass Tetraselmis sp. which was modified with a CTAB surfactant to produce Tetra-Alg-CTAB adsorbent as MO and MB adsorbents has been successfully carried out. The surface morphology of Tetra-Alg-CTAB illustrates that the grains attached to the surface produced by the CTAB surfactant modification efficiently enhanced adsorption capacity. Tetra-Alg-CTAB adsorbent was very effective in the adsorption of anionic MO dyes and less effective against cationic MB. MO adsorption by Tetra-Alg-CTAB was optimum at pH 10, a contact time of 90 min, and a concentration of 250 mg L−1. Tetra-Alg-CTAB adsorbent has a relatively large adsorption rate and capacity compared to the unmodified and Na+ ion-modified biomass (Tetra-Alg and Tetra-Alg-Na) towards the anionic MO dye. The best isotherm model was found to be the Langmuir isotherm, as it fits the adsorption experimental data well at equilibrium. On the other hand, the PSO model was found to be the most suitable adsorption kinetic model for this adsorption study. The reuse of Tetra-Alg-CTAB was carried out four times with adsorption percent > 70%, and the adsorbent was very effective in the adsorption of anionic dyes such as MO. These results proved that Tetra-Alg-CTAB could be employed as an alternative to commercial activated carbon for the removal of lead from the wastewater industry.

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/molecules28237839/s1, Table S1: Chemical Properties and Characteristics of MO and MB, Figure S1: Element mapping by SEM/EDX of Tetra-Alg, Figure S2: Element mapping by SEM/EDX of Tetra-Alg-Na, Figure S3: Element mapping by SEM/EDX of Tetra-Alg-CTAB.

Author Contributions

Methodology, B., I., S. (Suharso), S. (Sumadi), S. (Sutarto) and K.Z.E.; Validation, B., S. (Suharso) and K.Z.E.; Formal analysis, H.M.A.; Investigation, I., S. (Sumadi), S. (Sutarto) and H.M.A.; Resources, H.M.A.; Data curation, B. and S. (Suharso); Writing—original draft, B., S. (Sumadi) and S. (Sutarto); Writing—review & editing, S. (Suharso) and K.Z.E.; Supervision, K.Z.E.; Funding acquisition, B. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by the Higher Education for Technology and Innovation (HETI) Project at Universitas Lampung based on the Research Innovation and Collaboration Program 2023 (contract numbers: 10606/UN26/KS.00.00/2023).

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The data presented in this study are available upon request.

Acknowledgments

The authors are grateful to Higher Education for Technology and Innovation (HETI) Project Universitas Lampung for funding this study based on Research innovation and collaboration program 2023. The researchers also express a high appreciation to the Center for the Development of Marine Cultivation (BBPBL) Lampung.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Çelekli, A.; Bozkurt, H. Predictive modeling of an azo metal complex dye sorption by pumpkin husk. Environ. Sci. Pollut. Res. 2013, 20, 7355–7366. [Google Scholar] [CrossRef] [PubMed]
  2. Ahmed, I.; Haque, F.; Rahman, M.A.; Parvez, M.A.K.; Mou, T.J. Screening of Methyl Red Degrading Bacteria Isolated from Textile Effluents of Savar Area, Dhaka, Bangladesh. Adv. Biosci. Biotechnol. 2020, 11, 301–318. [Google Scholar] [CrossRef]
  3. Forgacs, E.; Cserháti, T.; Oros, G. Removal of synthetic dyes from wastewaters: A review. Environ. Int. 2004, 30, 953–971. [Google Scholar] [CrossRef] [PubMed]
  4. Buhani; Halimah, S.N.; Suharso; Sumadi. Utilization of activated carbon from candlenut shells (Aleurites moluccana) as methylene blue adsorbent. Rasayan J. Chem. 2022, 15, 124–131. [Google Scholar] [CrossRef]
  5. Ma, S.; Lee, S.; Kim, K.; Im, J.; Jeon, H. Purification of organic pollutants in cationic thiazine and azo dye solutions using plasma-based advanced oxidation process via submerged multi-hole dielectric barrier discharge. Sep. Purif. Technol. 2021, 255, 117715. [Google Scholar] [CrossRef]
  6. Nath, I.; Chakraborty, J.; Heynderickx, P.M.; Verpoort, F. Engineered synthesis of hierarchical porous organic polymers for visible light and natural sunlight induced rapid degradation of azo, thiazine and fluorescein based dyes in a unique mechanistic pathway. Appl. Catal. B 2018, 227, 102–113. [Google Scholar] [CrossRef]
  7. Teng, M.; Qiao, J.; Li, F.; Bera, P.K. Electrospun mesoporous carbon nanofibers produced from phenolic resin and their use in the adsorption of large dye molecules. Carbon 2012, 50, 2877–2886. [Google Scholar] [CrossRef]
  8. Khan, T.A.; Khan, E.A. Removal of basic dyes from aqueous solution by adsorption onto binary iron-manganese oxide coated kaolinite: Non-linear isotherm and kinetics modeling. Appl. Clay Sci. 2015, 107, 70–77. [Google Scholar] [CrossRef]
  9. Gupta, V.; Khamparia, S.; Tyagi, I.; Jaspal, D.; Malviya, A. Decolorization of mixture of dyes: A critical review. Glob. J. Environ. Sci. Manag. 2015, 1, 71–94. [Google Scholar]
  10. Sana, D.; Jalila, S. A comparative study of adsorption and regeneration with different agricultural wastes as adsorbents for the removal of methylene blue from aqueous solution. Chin. J. Chem. Eng. 2017, 25, 1282–1287. [Google Scholar] [CrossRef]
  11. Umpierres, C.S.; Prola, L.D.; Adebayo, M.A.; Lima, E.C.; Dos Reis, G.S.; Kunzler, D.D.; Dotto, G.L.; Arenas, L.T.; Benvenutti, E.V. Mesoporous Nb2O5/SiO2 material obtained by sol-gel method and applied as adsorbent of crystal violet dye. Environ. Technol. 2017, 38, 566–578. [Google Scholar] [CrossRef] [PubMed]
  12. Deb, A.; Kanmani, M.; Debnath, A.; Bhowmik, K.L.; Saha, B. Ultrasonic assisted enhanced adsorption of methyl orange dye onto polyaniline impregnated zinc oxide nanoparticles: Kinetic, isotherm and optimization of process parameters. Ultrason. Sonochem. 2019, 54, 290–301. [Google Scholar] [CrossRef] [PubMed]
  13. Alventosa-deLara, E.; Barredo-Damas, S.; Alcaina-Miranda, M.; Iborra-Clar, M. Ultrafiltration technology with a ceramic membrane for reactive dye removal: Optimization of membrane performance. J. Hazard. Mater. 2012, 209, 492–500. [Google Scholar] [CrossRef] [PubMed]
  14. Gupta, V.K.; Ali, I.; Saleh, T.A.; Nayak, A.; Agarwal, S. Chemical treatment technologies for waste-water recycling—An overview. RSC Adv. 2012, 2, 6380–6388. [Google Scholar] [CrossRef]
  15. Paul, J.; Rawat, K.; Sarma, K.; Sabharwal, S. Decoloration and degradation of Reactive Red-120 dye by electron beam irradiation in aqueous solution. Appl. Radiat. Isot. 2011, 69, 982–987. [Google Scholar] [CrossRef]
  16. Ashokan, P.; Asaithambi, M.; Sivakumar, V.; Sivakumar, P. Adsorptive removal of basic orange 21 dye by an adsorbent prepared from Adenanthera paronina L seeds. Rasayan J. Chem. 2022, 15, 1596–1607. [Google Scholar] [CrossRef]
  17. Vatandoostarani, S.; Lotfabad, T.B.; Heidarinasab, A.; Yaghmaei, S. Degradation of azo dye methyl red by Saccharomyces cerevisiae ATCC 9763. Int. Biodeterior. Biodegrad. 2017, 125, 62–72. [Google Scholar] [CrossRef]
  18. Buhani; Wijayanti, T.A.; Suharso; Sumadi; Ansori, M. Application of modified green algae Nannochloropsis sp. as adsorbent in the simultaneous adsorption of Methylene Blue and Cu(II) cations in solution. Sustain. Environ. Res. 2021, 31, 17. [Google Scholar] [CrossRef]
  19. Buhani; Suharso; Aditiya, I.; Kausar, R.A.; Sumadi; Rinawati. Production of a Spirulina sp. algae hybrid with a silica matrix as an effective adsorbent to absorb crystal violet and methylene blue in a solution. Sustain. Environ. Res. 2019, 29, 1–11. [Google Scholar] [CrossRef]
  20. Guler, U.A.; Ersan, M.; Tuncel, E.; Dügenci, F. Mono and simultaneous removal of crystal violet and safranin dyes from aqueous solutions by HDTMA-modified Spirulina sp. Process Saf. Environ. Prot. 2016, 99, 194–206. [Google Scholar] [CrossRef]
  21. Buhani; Suharso; Miftahza, N.; Permatasari, D.; Sumadi. Improved adsorption capacity of Nannochloropsis sp. through modification with cetyltrimethylammonium bromide on the removal of methyl orange in solution. Adsorpt. Sci. Technol. 2021, 2021, 1641074. [Google Scholar] [CrossRef]
  22. Angelova, R.; Baldikova, E.; Pospiskova, K.; Maderova, Z.; Safarikova, M.; Safarik, I. Magnetically modified Sargassum horneri biomass as an adsorbent for organic dye removal. J. Clean. Prod. 2016, 137, 189–194. [Google Scholar] [CrossRef]
  23. Yadav, A.; Bagotia, N.; Yadav, S.; Sharma, A.K.; Kumar, S. Adsorptive studies on the removal of dyes from single and binary systems using Saccharum munja plant-based novel functionalized CNT composites. Environ. Technol. Innov. 2021, 24, 102015. [Google Scholar] [CrossRef]
  24. Buhani; Rinawati; Suharso; Yuliasari, D.P.; Yuwono, S.D. Removal of Ni (II), Cu (II), and Zn (II) ions from aqueous solution using Tetraselmis sp. biomass modified with silica-coated magnetite nanoparticles. Desalin. Water Treat. 2017, 80, 203–213. [Google Scholar] [CrossRef]
  25. Daneshvar, E.; Vazirzadeh, A.; Niazi, A.; Kousha, M.; Naushad, M.; Bhatnagar, A. Desorption of methylene blue dye from brown macroalga: Effects of operating parameters, isotherm study and kinetic modeling. J. Clean. Prod. 2017, 152, 443–453. [Google Scholar] [CrossRef]
  26. Harris, P.O.; Ramelow, G.J. Binding of metal ions by particulate biomass derived from Chlorella vulgaris and Scenedesmus quadricauda. Environ. Sci. Technol. 1990, 24, 220–228. [Google Scholar] [CrossRef]
  27. Veglio’, F.; Beolchini, F.; Toro, L. Kinetic modeling of copper biosorption by immobilized biomass. Ind. Eng. Chem. Res. 1998, 37, 1107–1111. [Google Scholar] [CrossRef]
  28. Chandra, T.S.; Mudliar, S.; Vidyashankar, S.; Mukherji, S.; Sarada, R.; Krishnamurthi, K.; Chauhan, V. Defatted algal biomass as a non-conventional low-cost adsorbent: Surface characterization and methylene blue adsorption characteristics. Bioresour. Technol. 2015, 184, 395–404. [Google Scholar] [CrossRef]
  29. Jing, X.; Cao, Y.; Zhang, X.; Wang, D.; Wu, X.; Xu, H. Biosorption of Cr (VI) from simulated wastewater using a cationic surfactant modified spent mushroom. Desalination 2011, 269, 120–127. [Google Scholar] [CrossRef]
  30. Yusof, A.M.; Malek, N.A.N.N. Removal of Cr (VI) and As (V) from aqueous solutions by HDTMA-modified zeolite Y. J. Hazard. Mater. 2009, 162, 1019–1024. [Google Scholar] [CrossRef]
  31. Bingol, A.; Aslan, A.; Cakici, A. Biosorption of chromate anions from aqueous solution by a cationic surfactant-modified lichen (Cladonia rangiformis (L.)). J. Hazard. Mater. 2009, 161, 747–752. [Google Scholar] [CrossRef] [PubMed]
  32. Chen, B.; Dong, J.; Li, B.; Xue, C.; Tetteh, P.A.; Li, D.; Gao, K.; Deng, X. Using a freshwater green alga Chlorella pyrenoidosa to evaluate the biotoxicity of ionic liquids with different cations and anions. Ecotoxicol. Environ. Saf. 2020, 198, 110604. [Google Scholar] [CrossRef] [PubMed]
  33. Kaczerewska, O.; Martins, R.; Figueiredo, J.; Loureiro, S.; Tedim, J. Environmental behaviour and ecotoxicity of cationic surfactants towards marine organisms. J. Hazard. Mater. 2020, 392, 122299. [Google Scholar] [CrossRef] [PubMed]
  34. Li, F.; Kuang, Y.; Liu, N.; Ge, F. Extracellular polymeric substrates of Chlorella vulgaris F1068 weaken stress of cetyltrimethyl ammonium chloride on ammonium uptake. Sci. Total Environ. 2019, 661, 678–684. [Google Scholar] [CrossRef] [PubMed]
  35. Alsawy, T.; Rashad, E.; El-Qelish, M.; Mohammed, R.H. A comprehensive review on the chemical regeneration of biochar adsorbent for sustainable wastewater treatment. NPJ Clean Water 2022, 5, 29. [Google Scholar] [CrossRef]
  36. Elgarahy, A.M.; Maged, A.; Elwakeel, K.Z.; El-Gohary, F.; El-Qelish, M. Tuning cationic/anionic dyes sorption from aqueous solution onto green algal biomass for biohydrogen production. Environ. Res. 2023, 216, 114522. [Google Scholar] [CrossRef] [PubMed]
  37. Elgarahy, A.M.; Elwakeel, K.Z.; Elshoubaky, G.A.; Mohammad, S.H. Microwave-accelerated sorption of cationic dyes onto green marine algal biomass. Environ. Sci. Pollut. Res. 2019, 26, 22704–22722. [Google Scholar] [CrossRef]
  38. Abd El-Ghaffar, M.A.; Abdel-Wahab, Z.H.; Elwakeel, K.Z. Extraction and separation studies of silver(I) and copper(II) from their aqueous solution using chemically modified melamine resins. Hydrometallurgy 2009, 96, 27–34. [Google Scholar] [CrossRef]
  39. Ai, L.; Zhang, C.; Liao, F.; Wang, Y.; Li, M.; Meng, L.; Jiang, J. Removal of methylene blue from aqueous solution with magnetite loaded multi-wall carbon nanotube: Kinetic, isotherm and mechanism analysis. J. Hazard. Mater. 2011, 198, 282–290. [Google Scholar] [CrossRef]
  40. Elgarahy, A.M.; Mostafa, H.Y.; Zaki, E.G.; ElSaeed, S.M.; Elwakeel, K.Z.; Akhdhar, A.; Guibal, E. Methylene blue removal from aqueous solutions using a biochar/gellan gum hydrogel composite: Effect of agitation mode on sorption kinetics. Int. J. Biol. Macromol. 2023, 232, 123355. [Google Scholar] [CrossRef]
  41. Liang, Y.-D.; He, Y.-J.; Wang, T.-T.; Lei, L.-H. Adsorptive removal of gentian violet from aqueous solution using CoFe2O4/activated carbon magnetic composite. J. Water Process. Eng. 2019, 27, 77–88. [Google Scholar] [CrossRef]
  42. AbdEl-Salam, A.; Ewais, H.; Basaleh, A. Silver nanoparticles immobilised on the activated carbon as efficient adsorbent for removal of crystal violet dye from aqueous solutions. A kinetic study. J. Mol. Liq. 2017, 248, 833–841. [Google Scholar] [CrossRef]
  43. Ebadollahzadeh, H.; Zabihi, M. Competitive adsorption of methylene blue and Pb (II) ions on the nano-magnetic activated carbon and alumina. Mater. Chem. Phys. 2020, 248, 122893. [Google Scholar] [CrossRef]
  44. Shao, Y.; Zhou, L.; Bao, C.; Ma, J.; Liu, M.; Wang, F. Magnetic responsive metal–organic frameworks nanosphere with core–shell structure for highly efficient removal of methylene blue. Chem. Eng. J. 2016, 283, 1127–1136. [Google Scholar] [CrossRef]
  45. Xin, X.; Wei, Q.; Yang, J.; Yan, L.; Feng, R.; Chen, G.; Du, B.; Li, H. Highly efficient removal of heavy metal ions by amine-functionalized mesoporous Fe3O4 nanoparticles. Chem. Eng. J. 2012, 184, 132–140. [Google Scholar] [CrossRef]
  46. Larraza, I.; López-Gónzalez, M.; Corrales, T.; Marcelo, G. Hybrid materials: Magnetite–polyethylenimine–montmorillonite, as magnetic adsorbents for Cr (VI) water treatment. J. Colloid Interface Sci. 2012, 385, 24–33. [Google Scholar] [CrossRef]
  47. Buhani, B.; Suharso, S.; Fitriyani, A.Y. Comparative Study of Adsorption Ability of Ni(II) and Zn(II) Ionic Imprinted Amino-Silica Hybrid Toward Target Metal in Solution. Asian J. Chem. 2013, 25, 2875–2880. [Google Scholar] [CrossRef]
  48. Huang, R.; Liu, Q.; Zhang, L.; Yang, B. Utilization of cross-linked chitosan/bentonite composite in the removal of methyl orange from aqueous solution. Water Sci. Technol. 2015, 71, 174–182. [Google Scholar] [CrossRef]
  49. Zhang, J.; Zhou, Q.; Ou, L. Kinetic, isotherm, and thermodynamic studies of the adsorption of methyl orange from aqueous solution by chitosan/alumina composite. J. Chem. Eng. Data 2012, 57, 412–419. [Google Scholar] [CrossRef]
  50. Sun, X.; Zhou, Y.; Zheng, X. Comparison of adsorption behaviors of Fe-La oxides co-loaded MgO nanosheets for the removal of methyl orange and phosphate in single and binary systems. J. Environ. Chem. Eng. 2020, 8, 104252. [Google Scholar] [CrossRef]
  51. Su, Y.; Jiao, Y.; Dou, C.; Han, R. Biosorption of methyl orange from aqueous solutions using cationic surfactant-modified wheat straw in batch mode. Desalin. Water Treat. 2014, 52, 6145–6155. [Google Scholar] [CrossRef]
  52. Hambisa, A.A.; Regasa, M.B.; Ejigu, H.G.; Senbeto, C.B. Adsorption studies of methyl orange dye removal from aqueous solution using Anchote peel-based agricultural waste adsorbent. Appl. Water Sci. 2023, 13, 24. [Google Scholar] [CrossRef]
  53. Jamwal, H.S.; Kumari, S.; Chauhan, G.S.; Reddy, N.; Ahn, J.-H. Silica-polymer hybrid materials as methylene blue adsorbents. J. Environ. Chem. Eng. 2017, 5, 103–113. [Google Scholar] [CrossRef]
  54. Siddiqui, S.H.; Uddin, M.K.; Isaac, R.; Aldosari, O.F. An Effective Biomass for the Adsorption of Methylene Blue Dye and Treatment of River Water. Adsorpt. Sci. Technol. 2022, 2022, 4143138. [Google Scholar] [CrossRef]
  55. Varghese, S.P.; Babu, A.T.; Babu, B.; Antony, R. γ-MnOOH nanorods: Efficient adsorbent for removal of methylene blue from aqueous solutions. J. Water Process. Eng. 2017, 19, 1–7. [Google Scholar] [CrossRef]
Molecules 28 07839 g001
Figure 1. Spectra of IR from (a) Tetra-Alg, (b) Tetra-Alg-Na, and (c) Tetra-Alg-CTAB.
Figure 1. Spectra of IR from (a) Tetra-Alg, (b) Tetra-Alg-Na, and (c) Tetra-Alg-CTAB.
Molecules 28 07839 g001
Molecules 28 07839 g002
Figure 2. SEM images and EDX spectra of (a,b) Tetra-Alg, (c,d) Tetra-Alg-Na, and (e,f) Tetra-Alg-CTAB.
Figure 2. SEM images and EDX spectra of (a,b) Tetra-Alg, (c,d) Tetra-Alg-Na, and (e,f) Tetra-Alg-CTAB.
Molecules 28 07839 g002
Molecules 28 07839 g003
Figure 3. Determination of the point of zero charge of the Tetra-Alg, Tetra-Na, and Tetra-Alg-CTAB.
Figure 3. Determination of the point of zero charge of the Tetra-Alg, Tetra-Na, and Tetra-Alg-CTAB.
Molecules 28 07839 g003
Molecules 28 07839 g004
Figure 4. Effect of interaction pH0 on % adsorption of MO-dye and MB-dye by Tetra-Alg, Tetra-Alg-Na, Tetra-Alg-CTAB (adsorbent mass: 0.1 g; solution volume: 25 mL; C0: 10 mg L−1; temperature: 27 ± 1 °C; agitation speed: 150 rpm; time: 60 min).
Figure 4. Effect of interaction pH0 on % adsorption of MO-dye and MB-dye by Tetra-Alg, Tetra-Alg-Na, Tetra-Alg-CTAB (adsorbent mass: 0.1 g; solution volume: 25 mL; C0: 10 mg L−1; temperature: 27 ± 1 °C; agitation speed: 150 rpm; time: 60 min).
Molecules 28 07839 g004
Molecules 28 07839 g005
Figure 5. Effect of contact time on % adsorption of MO and MB by Tetra-Alg, Tetra-Alg-Na, Tetra-Alg-CTAB (adsorbent mass: 0.1 g; solution volume: 25 mL; C0: 10 mg L−1; temperature: 27 ± 1 °C; agitation speed: 150 rpm; pH: 10).
Figure 5. Effect of contact time on % adsorption of MO and MB by Tetra-Alg, Tetra-Alg-Na, Tetra-Alg-CTAB (adsorbent mass: 0.1 g; solution volume: 25 mL; C0: 10 mg L−1; temperature: 27 ± 1 °C; agitation speed: 150 rpm; pH: 10).
Molecules 28 07839 g005
Molecules 28 07839 g006aMolecules 28 07839 g006b
Figure 6. Intraparticle diffusion plot on adsorption of (a) MO and (b) MB on Tetra-Alg, Tetra-Alg-Na, Tetra-Alg-CTAB.
Figure 6. Intraparticle diffusion plot on adsorption of (a) MO and (b) MB on Tetra-Alg, Tetra-Alg-Na, Tetra-Alg-CTAB.
Molecules 28 07839 g006aMolecules 28 07839 g006b
Molecules 28 07839 g007
Figure 7. Effect of initial concentration on the amount of MO and MB adsorbed on Tetra-Alg, Tetra-Alg-Na, Tetra-Alg-CTAB (adsorbent mass: 0.1 g; solution volume: 25 mL; temperature: 27 ± 1 °C; agitation speed: 150 rpm; pH: 10; time: 90 min).
Figure 7. Effect of initial concentration on the amount of MO and MB adsorbed on Tetra-Alg, Tetra-Alg-Na, Tetra-Alg-CTAB (adsorbent mass: 0.1 g; solution volume: 25 mL; temperature: 27 ± 1 °C; agitation speed: 150 rpm; pH: 10; time: 90 min).
Molecules 28 07839 g007
Molecules 28 07839 g008
Figure 8. Reusability number efficiency of the adsorption of MO on Tetra-Alg, Tetra-Alg-Na, Tetra-Alg-CTAB.
Figure 8. Reusability number efficiency of the adsorption of MO on Tetra-Alg, Tetra-Alg-Na, Tetra-Alg-CTAB.
Molecules 28 07839 g008
Table 1. Pseudo-second-order kinetics for the adsorption of MO and MB on Tetra-Alg, Tetra-Alg-Na, Tetra-Alg-CTAB (adsorbent mass: 0.1 g; solution volume: 25 mL; C0: 10 mg L−1; temperature: 27 ± 1 °C; agitation speed: 150 rpm; pH: 10).
Table 1. Pseudo-second-order kinetics for the adsorption of MO and MB on Tetra-Alg, Tetra-Alg-Na, Tetra-Alg-CTAB (adsorbent mass: 0.1 g; solution volume: 25 mL; C0: 10 mg L−1; temperature: 27 ± 1 °C; agitation speed: 150 rpm; pH: 10).
AdsorbentPseudo-Second-Order (PSO)
MOMB
qe-exp
(mg g−1)		qe-PSO
(mg g−1)		k2 × 10−3
(g mg−1 min−1)		R2qe-exp
(mg g−1)		qe-PSO
(mg g−1)		k2 × 10−3
(g mg−1 min−1)		R2
Tetra-Alg0.3010.2906.0320.9992.3072.3400.7580.999
Tetra-Alg-Na0.3570.3579.5510.9942.4072.3630.7490.999
Tetra-Alg-CTAB2.4792.47512.6400.9991.4671.4450.4730.997
Table 2. Intra-particle diffusion model for MO and MB adsorption on Tetra-Alg, Tetra-Alg-Na, Tetra-Alg-CTAB.
Table 2. Intra-particle diffusion model for MO and MB adsorption on Tetra-Alg, Tetra-Alg-Na, Tetra-Alg-CTAB.
Adsorbent–AdsorbateInitial Linear PortionSecond Linear Portion
ki1C1R12ki2C2R22
(mg g−1 min0.5)(mg g−1)(mg g−1 min0.5)(mg g−1)
Tetra-Alg-MO0.0050.6030.9510.0370.0290.899
Tetra-Alg-Na-MO0.0220.2030.9350.040.0530.973
Tetra-Alg-CTAB-MO0.0652.0280.9470.0442.1720.957
Tetra-Alg-MB0.0592.0240.9510.0302.2610.900
Tetra-Alg-Na-MB0.0651.8740.9890.0172.2380.926
Tetra-Alg-CTAB-MB0.0371.1640.9470.0241.2870.940
Table 3. Adsorption isotherm parameters of MO and MB on Tetra-Alg, Tetra-Alg-Na, Tetra-Alg-CTAB (adsorbent mass: 0.1 g; solution volume: 25 mL; temperature: 27 ± 1 °C; agitation speed: 150 rpm; pH: 10; time: 90 min).
Table 3. Adsorption isotherm parameters of MO and MB on Tetra-Alg, Tetra-Alg-Na, Tetra-Alg-CTAB (adsorbent mass: 0.1 g; solution volume: 25 mL; temperature: 27 ± 1 °C; agitation speed: 150 rpm; pH: 10; time: 90 min).
Adsorbent–AdsorbateAdsorption Isotherm Parameters
LangmuirFreundlich
qm
(mg g−1)		KL × 10−2
(L mg−1)		R2KF × 10−2
((mg g−1)
(L mg−1)1/n)		nR2
Tetra-Alg-MO51.6310.3610.94614.8940.3100.985
Tetra-Alg-Na-MO94.3890.2090.91413.3640.3620.990
Tetra-Alg-CTAB-MO128.3693.5200.93318.0590.2350.994
Tetra-Alg-MB50.0553.3950.9150.4071.1870.995
Tetra-Alg-Na-MB58.1552.4230.9190.6.681.1240.990
Tetra-Alg-CTAB-MB51.0130.2390.9330.2240.7070.991
Table 4. Comparison of adsorption capabilities of several adsorbents for the dyes MO and MB.
Table 4. Comparison of adsorption capabilities of several adsorbents for the dyes MO and MB.
AdsorbentDyesqm (mg g−1)References
Cross-linked chitosanMO89.29[48]
Chitosan/alumina compositeMO33.00[49]
Fe-La oxides co-loaded MgO (Fe-La/MgO) nanosheetsMO30.38[50]
Modified wheat straw 3.0MO50.40[51]
Anchote peelMO103.03[52]
Tetra-Alg-CTABMO128.37This research
Magnetite-loaded multi-wall carbon nanotubesMB48.00[39]
Fe3O4@MIL-100(Fe) magnetite compositeMB74.00[44]
Silica-Polymer hybridMB87.00[53]
Spirulina sp. algae hybrid with a silica matrixMB74.00[19]
Neolamarckia cadamba leavesMB101.40[54]
Tetra-Alg-CTABMB58.15This research
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Buhani; Istikomah; Suharso; Sumadi; Sutarto; Alghamdi, H.M.; Elwakeel, K.Z. Cationic Surfactant-Modified Tetraselmis sp. for the Removal of Organic Dyes from Aqueous Solution. Molecules 2023, 28, 7839. https://doi.org/10.3390/molecules28237839

AMA Style

Buhani, Istikomah, Suharso, Sumadi, Sutarto, Alghamdi HM, Elwakeel KZ. Cationic Surfactant-Modified Tetraselmis sp. for the Removal of Organic Dyes from Aqueous Solution. Molecules. 2023; 28(23):7839. https://doi.org/10.3390/molecules28237839

Chicago/Turabian Style

Buhani, Istikomah, Suharso, Sumadi, Sutarto, Huda M. Alghamdi, and Khalid Z. Elwakeel. 2023. "Cationic Surfactant-Modified Tetraselmis sp. for the Removal of Organic Dyes from Aqueous Solution" Molecules 28, no. 23: 7839. https://doi.org/10.3390/molecules28237839

Article Metrics

Back to TopTop