Adsorption Technique for Water Purification

A special issue of Separations (ISSN 2297-8739). This special issue belongs to the section "Materials in Separation Science".

Deadline for manuscript submissions: closed (10 March 2024) | Viewed by 9262

Special Issue Editor


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Guest Editor
Department of Chemistry, Northwestern University, Evanston, IL 60208, USA
Interests: metal–organic frameworks; emerging contaminants; heavy metals; crystalline materials; luminescence; sorption; wastewater treatment

Special Issue Information

Dear Colleagues,

Water is the most common substance on planet Earth and the most valuable natural resource as it is essential for the survival of all living organisms. Nowadays, water pollution is a serious threat due to the tremendous increase in world population, massive industrialization, urbanization, as well as global climate changes, which affect the quality of water, and thus the livelihoods of all people. In recent decades, a number of technologies have addressed the emerging issue of water purification. Among these techniques, adsorption is one of the most attractive and widely used, due to its simplicity, low-cost, and high efficiency of the method. Thus far, although a variety of materials, including natural compounds, nanomaterials, metal–organic frameworks, etc., serve as excellent sorbents against emergent contaminants, the ominous predictions for the coming decades generate a growing research interest in this field and a continuous need for novel, state-of-the art adsorbents. 

Dr. Anastasia D. Pournara
Guest Editor

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Keywords

  • adsorption
  • purification technology
  • wastewater treatment
  • emergent contaminants
  • environmental applications
  • water purification
  • sorbents

Published Papers (5 papers)

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Research

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19 pages, 3072 KiB  
Article
Evaluation of Carbonized Corncobs for Removal of Microcystins and Nodularin-R from Water
by Hasaruwani S. Kiridena, Sharmila I. Thenuwara, Manjula M. Kandage, Norman Peiffer, Michal Marszewski and Dragan Isailovic
Separations 2024, 11(3), 84; https://doi.org/10.3390/separations11030084 - 13 Mar 2024
Viewed by 1075
Abstract
Microcystins (MCs) and nodularins (NODs) are cyanotoxins that can be found in water bodies during cyanobacterial harmful algal blooms (cyanoHABs). Consumption of water contaminated with cyanotoxins leads to health risks for humans and animals. Herein, corncob-based biochar and activated carbon (AC) were initially [...] Read more.
Microcystins (MCs) and nodularins (NODs) are cyanotoxins that can be found in water bodies during cyanobacterial harmful algal blooms (cyanoHABs). Consumption of water contaminated with cyanotoxins leads to health risks for humans and animals. Herein, corncob-based biochar and activated carbon (AC) were initially investigated for the sorption of six common MC congeners (MC-RR, MC-YR, MC-LR, MC-LA, MC-LW, and MC-LF) and nodularin-R (NOD-R) from spiked water. Biochar was prepared by refluxing commercial corncob with HCl and heating it to 250, 300, or 350 °C. AC was prepared by chemical activation of corncob with H3PO4 at 500 °C under a nitrogen atmosphere. Low-temperature nitrogen adsorption measurements confirmed that H3PO4-AC has a higher specific surface area (≈1100 m2/g) and total pore volume (≈0.75 cm3/g) than biochar and commercial AC. H3PO4-AC showed the maximum efficacy, among all corncob-based sorbents, to remove MCs and NOD-R from water as confirmed by experiments that involved sample analyses by ultrahigh-pressure liquid chromatography-mass spectrometry (UHPLC-MS). The effect of natural organic matter (NOM) on the adsorption of MCs was checked by incubating sorbents with Lake Erie water collected during cyanoHABs from 2020 to 2022. The total concentration (extracellular and intracellular) of studied MC congeners ranged from 1.37 µg/L to 438.51 µg/L and 50 mg of H3PO4-AC completely removed them from 3 mL of lake water. The effect of water pH on cyanotoxin adsorption was studied at pH values of 5.5, 7.0, and 8.5 at both a lower (10 μg/L each) and a higher (50 μg/L each) toxin concentration. Removal was influenced by solution pH at both concentrations when using biochar, while only at higher toxin concentration when using H3PO4-AC. At higher MC and NOD-R concentrations, competitive adsorption was prominent, and overall, the adsorption increased at acidic pH (5.5). The study results suggest that processed corncobs can remove a significant amount of MCs and NOD-R from water, and the measured sorption capacity of H3PO4-AC was ~20 mg of MC-LR and NOD-R per g of this sorbent. Full article
(This article belongs to the Special Issue Adsorption Technique for Water Purification)
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15 pages, 6381 KiB  
Article
Comparison of Acid- and Base-Modified Biochar Derived from Douglas Fir for Removal of Copper (II) from Wastewater
by Beatrice Arwenyo, Prashan M. Rodrigo, Olalekan A. Olabode, Hashani P. Abeysinghe, Jessie N. Tisdale, Rose C. Azuba and Todd E. Mlsna
Separations 2024, 11(3), 78; https://doi.org/10.3390/separations11030078 - 1 Mar 2024
Cited by 1 | Viewed by 1076
Abstract
Copper is a non-biodegradable heavy metal, and high levels in water bodies cause serious environmental and health issues. Douglas fir biochar has a higher number of carboxylic, phenolic, and lactonic groups, which provide suitable active sites for copper removal. Douglas fir biochar (BC) [...] Read more.
Copper is a non-biodegradable heavy metal, and high levels in water bodies cause serious environmental and health issues. Douglas fir biochar has a higher number of carboxylic, phenolic, and lactonic groups, which provide suitable active sites for copper removal. Douglas fir biochar (BC) was modified using 20% solutions of KOH (KOH/BC), H2SO4, (H2SO4/BC), and Na2CO3 (Na2CO3/BC). All materials were characterized using SEM, SEM-EDS, FTIR, TGA, XRD, BET, and elemental analysis. These modifications were done to compare the activations of those sites by measuring copper removal efficiencies. KOH/BC, H2SO4/BC, and Na2CO3/BC materials gave surface areas of 389.3, 326.7, and 367.9 m2 g−1, respectively, compared with pristine biochar with a surface area of 578.9 m2 g−1. The maximum Langmuir adsorption capacities for Na2CO3/BC, KOH/BC, BC, and H2SO4/BC were 24.79, 18.31, 17.38, and 9.17 mg g−1, respectively. All three modifications gave faster kinetics at 2 mg/L initial copper concentrations (pH 5) compared with pristine BC. The copper removal efficiency was demonstrated in four different spiked real water matrices. The copper removals of all four water matrices were above 90% at 2 mg/L initial concentration with a 2 g/L biochar dosage. The competitive effects of Pb2+, Zn2+, Cd2+, and Mg2+ were studied at equimolar concentrations of Cu2+ and competitive ions for all four materials. Full article
(This article belongs to the Special Issue Adsorption Technique for Water Purification)
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20 pages, 6288 KiB  
Article
Photocatalytic Removal of Crystal Violet Dye Utilizing Greenly Synthesized Iron Oxide Nanoparticles
by Mohamed Taha Yassin, Fatimah O. Al-Otibi and Abdulaziz A. Al-Askar
Separations 2023, 10(9), 513; https://doi.org/10.3390/separations10090513 - 17 Sep 2023
Cited by 3 | Viewed by 1561
Abstract
The presence of synthetic industrial dyes in the environment poses significant risks to aquatic ecosystems, human health, and economies. This study aims to synthesize iron oxide nanoparticles (IONPs) using a green method, analyze them using physicochemical techniques, and examine the effectiveness with which [...] Read more.
The presence of synthetic industrial dyes in the environment poses significant risks to aquatic ecosystems, human health, and economies. This study aims to synthesize iron oxide nanoparticles (IONPs) using a green method, analyze them using physicochemical techniques, and examine the effectiveness with which they photocatalytically degrade crystal violet dye in sunlight. Fourier transform infrared spectroscopy (FTIR) analysis revealed that the biogenic IONPs showed a UV peak at a wavelength of 241 nm, with functional groups including phenols, alkynes, and alkenes. X-ray diffraction (XRD) analysis confirmed the amorphous nature of the bioinspired IONPs. The mean diameter of the biogenic IONPs was 49.63 ± 9.23 nm, and they had a surface charge of −5.69 mV. The efficiency with which the synthesized IONPs removed the crystal violet dye was evaluated under dark and sunlight conditions. The removal efficiency was found to be concentration and time dependent, with a peak removal percentage of 99.23% being achieved when the IONPs were exposed to sunlight for 210 min. The biogenic IONPs also demonstrated antioxidant activity, with a relative IC50 value of 64.31 µg/mL. In conclusion, biogenic IONPs offer a viable and environmentally friendly approach for eradicating industrial synthetic dyes and remediating contaminated environments and aquatic ecosystems. Full article
(This article belongs to the Special Issue Adsorption Technique for Water Purification)
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27 pages, 1000 KiB  
Review
Biochar-Based Adsorbents for Pesticides, Drugs, Phosphorus, and Heavy Metal Removal from Polluted Water
by Mariana Bocșa, Stelian Pintea, Ildiko Lung, Ocsana Opriș, Adina Stegarescu, Muhammad Humayun, Mohamed Bououdina, Maria-Loredana Soran and Stefano Bellucci
Separations 2023, 10(10), 533; https://doi.org/10.3390/separations10100533 - 6 Oct 2023
Cited by 1 | Viewed by 2424
Abstract
Water contamination is a ubiquitous issue for all countries and territories worldwide. Among others, pesticides, drugs, heavy metals, and phosphates play a special role in terms of pollutants due to their toxicity and large-scale applications in industrial and agricultural activities. In order to [...] Read more.
Water contamination is a ubiquitous issue for all countries and territories worldwide. Among others, pesticides, drugs, heavy metals, and phosphates play a special role in terms of pollutants due to their toxicity and large-scale applications in industrial and agricultural activities. In order to provide cleaner freshwater for the world’s population, two types of actions are required: preventing/limiting the pollution that might occur during our daily activities and decontaminating the already exposed/contaminated water sources. One of the key points in the decontamination process is to create as few as possible side effects with the solutions applied. For this reason, in the case of the mentioned types of pollutants but not limited only to them, the use of environmentally friendly materials is more than welcome. Biochar qualifies as one of these materials, and its field of applications expands to larger scientific and industrial areas every day. Moreover, it can be functionalized in order to improve its properties in terms of pollutant removal efficiency. This paper summarizes the most recent developments in the field of water decontamination using biochar or biochar-based materials in order to remove pesticides, drugs, heavy metals, and phosphates from contaminated aqueous environments. Also, the removal of phosphorus from wastewater using biochar is considered. This removal can be a key controlling factor for the wastewater, which is obtained as a residual of agricultural activities. Indeed, due to the excessive use of chemical fertilizers, eutrophication in such kinds of wastewater can be a serious challenge. Full article
(This article belongs to the Special Issue Adsorption Technique for Water Purification)
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24 pages, 4381 KiB  
Review
Recent Applications of Carbon Nanotubes for Separation and Enrichment of Lead Ions
by Krystyna Pyrzynska
Separations 2023, 10(3), 152; https://doi.org/10.3390/separations10030152 - 23 Feb 2023
Cited by 7 | Viewed by 2593
Abstract
Lead is one of the most toxic heavy metals released into the environment through industrial sources. Its direct determination is often a problem due to the presence of relatively complex matrices as well as low content. Thus, the additional separation and preconcentration steps [...] Read more.
Lead is one of the most toxic heavy metals released into the environment through industrial sources. Its direct determination is often a problem due to the presence of relatively complex matrices as well as low content. Thus, the additional separation and preconcentration steps are necessary in the analytical procedures. Carbon nanotubes (CNTs) continue to attract significant interest for these purposes as they exhibit a high specific surface area, exceptional porosities, and numerous adsorption sites. The modified CNTs with active groups, reagents, or materials have been widely explored using more mutual interactions that can significantly improve their sorption capacity and selectivity. This paper summarizes the recent developments from 2017 in the application of carbon nanotubes for the separation of Pb(II) and its enrichment/removal from the matrix components. Attention is given to oxidized CNTs, their modification with complexing compounds, functionalization with metal oxides and polymers, new nanocomposites, and carbon nanotube membranes. Full article
(This article belongs to the Special Issue Adsorption Technique for Water Purification)
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