Search Results (32)

Winery wastewater, characterized by high organic load, fluctuating pH, and seasonal variability, presents a major environmental challenge for sustainable water management in viticulture regions. Recent advances in bio-based polymer composites, particularly those incorporating cellulose and chitosan matrices blended with synthetic polymers such as polyacrylamide (PAM), polyvinyl alcohol (PVA), and polyethylene glycol (PEG), provide promising possibilities for effective wastewater treatment and water reuse in irrigation. This review critically explores the synthesis, structural properties, and functional performance of cellulose/chitosan-based composites, with a particular emphasis on their adsorption, flocculation, and biodegradability in the context of winery effluent treatment. Evidence from recent laboratory- and pilot-scale studies highlights the significance of pH-responsive functional groups, electrostatic interactions, and hydrogen bonding in controlling pollutant capture and regeneration efficiency. While notable removal efficiencies of these composites have been demonstrated to exceed 85–95% for COD, 80–98% for turbidity, and >90% for heavy metals, challenges remain in terms of regeneration, long-term field applicability, and scale-up. Overall, biopolymer composites represent a promising pathway toward sustainable wastewater treatment and irrigation reuse in winery operations. Full article

Textile industries release dyes into wastewater, and when present above certain levels, these dyes pose serious risks because of their high toxicity. This study investigates the removal of Sunset Yellow (SY) and Methylene Violet (MV) dyes from wastewater using chitosan (CS) and polysilicate acid (pSi) in the structure of aluminum-based coagulants, resulting in hybrid formulations (CS@Al, Al/pSi, and CS@Al/pSi). Among the various treatment methods that have been applied for the removal of dyes, the coagulation/flocculation process was chosen in the present study, as it is a cheap and effective method. Coagulation performance was optimized for pH, coagulant dosage, temperature and mixing time. The Al/pSi coagulant achieved nearly complete SY removal (98.8%) at 25 mg/L dosage and pH 3.0. MV removal in single-dye solutions was limited, with Al/pSi achieving only 26.6% removal at pH 3.0. However, in mixed-dye systems (SY/MV), synergistic interactions increased MV removal up to 94.4% and SY removal to 100%. Hybrid CS@Al/pSi showed lower SY removal (36.4%) for SY at 50 mg/L but provided stable floc formation, particularly in mixtures of anionic and cationic dyes. Application to real textile wastewater confirmed the high efficiency of the optimized coagulants, particularly with Al/pSi_20,A and AlCl₃, indicating their potential for industrial wastewater treatment. SEM, EDS, XRD, and FTIR analyses revealed structural consolidation, increased surface area, and successful dye adsorption, explaining the high removal efficiency. Full article

Chitosan, a naturally abundant and biodegradable biopolymer derived from chitin found in crustacean shells, has emerged as a promising material for addressing environmental challenges. Its reactive amino and hydroxyl groups enable diverse interaction mechanisms. This makes it effective for removing heavy metals, dyes, pharmaceuticals, and other contaminants from water. However, the limitations of native chitosan, such as poor solubility and mechanical strength, necessitate strategic modifications. This review comprehensively examines recent advances in chitosan derivatives and composites. It focuses on modern modification strategies, such as chemical, physical, and composite formation, that enhance stability, selectivity, and efficiency. It explores the design principles of high-performance composites. It also details the multifaceted mechanisms of pollutant removal, including adsorption, catalysis, membrane filtration, and flocculation. Critical practical challenges are critically assessed. These include scalability, regeneration, lifecycle sustainability, and real-world implementation. Furthermore, emerging trends are highlighted. These integrate circular economy principles, seafood waste valorization, and digital optimization through the use of artificial intelligence. By consolidating current knowledge, this review aims to bridge the gap between laboratory innovations and large-scale environmental applications. It guides the development of intelligent, scalable, and ecologically responsible solutions based on this remarkable biopolymer. Full article

Chitosan is a natural polymer derived from chitin through the deacetylation process. It has emerged as a key ingredient in sustainable wastewater treatment, due to its biodegradability, non-toxicity, and low cost. This biopolymer possesses abundant functional groups, such as -NH₂ and -OH, that efficiently interact with pollutants. This review offers a comprehensive evaluation of pollutant separation techniques involving chitosan-based materials, including adsorption, membrane filtration, flocculation, and photocatalysis. It further examines the underlying adsorption mechanisms, emphasizing how pollutants interact with chitosan and its derivatives at the molecular level. Special focus is given to various modifications of chitosan, alongside a comparative assessment of different chitosan-based adsorbents (hydrogels, nanoparticles, nanocomposites, microspheres, nanofibers, etc.), highlighting their performance in removing heavy metals, dyes, and emerging organic pollutants. The reviewed performance of these polymeric materials from 2015–2025 not only gives an insight about the recent advancement but also points the need for the design of high-performing chitosan-based adsorbents with applications in real water matrices. Full article

Natural organic matter (NOM) in surface waters is a major challenge for drinking water treatment due to its role in the formation of disinfection byproducts (DBPs) during chlorination. This study evaluated the performance of chitosan, a biodegradable coagulant, dissolved in acetic, lactic, and L-ascorbic acids for NOM removal under three turbidity levels (403, 1220, and 5038 NTU). Jar tests were conducted using raw water from the Río Grande de Añasco (Puerto Rico), and TOC, DOC, and UV₂₅₄ were measured at multiple time points. TOC removal ranged from 39.8% to 74.3%, with the highest performance observed in high-turbidity water treated with chitosan–L-ascorbic acid. DOC and UV₂₅₄ reductions followed similar trends, with maximum removals of 76.4% and 76.2%, respectively. Estimated THM formation potential (THMFP) was reduced by up to 81.6%. Across all acids, flocculation efficiencies exceeded 95%. Compared to conventional aluminum-based coagulants, chitosan demonstrated comparable performance, while offering environmental benefits. These results confirm the potential of chitosan–acid systems for effective organic matter removal and DBP control, supporting their application as sustainable alternatives in drinking water treatment. Full article

Natural coagulants have gained significant attention as effective agents for wastewater treatment, particularly in the removal of heavy metals. This study conducts a comprehensive bibliometric analysis of 268 publications over the past decade, aiming to assess research trends and developments in the application of natural coagulants in wastewater management. The analysis reveals a marked increase in publication output, with the number of articles rising from just five in 2015 to fifty-one in 2024, indicating a growing global awareness and investment in sustainable wastewater treatment practices. “Environmental science” emerges as the leading discipline, accounting for 31.3% of the total publications. Notably, Malaysia is identified as the foremost contributor, with 60 publications and 1149 citations, followed by India and Brazil, highlighting the robust research activity in these regions. The study identifies key natural coagulants, such as Moringa oleifera and chitosan, which are frequently cited for their efficacy in reducing heavy metal concentrations and improving overall water quality. Leading funding organizations, such as the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior in Brazil, have significantly contributed to the growth of this field by financing numerous studies. Prominent journals, including the Journal of Environmental Chemical Engineering and Water Research, play a crucial role in disseminating research findings and advancing knowledge in this area. These publications are vital for sharing innovative methodologies and effective treatment solutions in the field of natural coagulants. Effective treatment methodologies identified in the literature include coagulation/flocculation and adsorption. The study highlights a variety of natural materials utilized for wastewater treatment, including plant-based coagulants derived from agricultural by-products, which not only address environmental concerns but also promote resource recovery. Full article

Eco-friendly pest management solutions are acknowledged as a crucial element in shaping the future of agriculture through sustainable practices. Achieving the maximum viable cell concentration while being cost-effective is the main goal of the downstream processing for efficient biomass-based microbial biopesticide production. The purpose of this study was to determine the effectiveness of chitosan flocculation in recovering bacterial Bacillus sp. BioSol021 biomass from broth cultivated using fruit juice industrial effluent as a medium, with the hypothesis of the synergistic effect of microbial and biopolymer components in phytopathogen suppression. Second-order polynomial models were used to calculate the influence of chitosan concentration and mixing speed on flocculation efficiency, settling velocity, and antibacterial activity against Aspergillus flavus (i.e., the inhibition zone diameter). The response surface approach, followed by desirability function optimization and the genetic algorithm were applied. The optimal values achieved in this study were 97.18%, 0.0369 mm/s, and 74.00 mm for flocculation efficiency, settling velocity, and inhibition zone diameter, respectively. The obtained results suggest that chitosan can be used as a flocculation agent for effective downstream processing, but also has a positive effect on the final product antimicrobial activity. Full article

The presence of silver nanoparticles (AgNPs) in water bodies has emerged as a new environmental concern and the efficient separation of these nanoparticles remains a critical challenge. Here, we developed novel magnetic nanoflocculants for the recovery of AgNPs from water. Alternating layers of biopolymers, in particular, chitosan, alginate, and polymeric bio-based soluble substances (BBS) derived from urban waste, were coated on magnetic nanoparticles via the layer-by-layer technique to prepare reusable magnetic nanoflocculants (MNFs). The MNFs obtained were characterized with diverse physicochemical techniques. Surface response methodology, based on the Doehlert matrix, has shown to be a useful tool to determine the effect of pH (in the range 5–9), concentration of AgNPs (7–20 mg L⁻¹), and MNFs (50–1000 mg L⁻¹) on the performance of AgNPs removal. The model predicts a high AgNPs removal percentage at low pH values and high MNF concentration. In particular, for the most efficient MNFs, 90% of AgNPs removal was obtained at pH 5 and 600 mg L⁻¹ MNF concentration. Additionally, the effects of AgNPs size, ionic strength, the presence of humic acids, and two types of surfactants (LAS anionic and TWEEN 20 nonionic) on the AgNPs removal were evaluated. Finally, recovery and reuse experiments showed that MNF made of Chitosan-BBS can be reused in ten cycles, losing only 30% of the initial removal capacity. Therefore, magnetic flocculation could represent a sustainable alternative for AgNPs separation with potential applications in water treatment and remediation of nanoparticle contamination. Full article

In this study, a new oleogel system was constructed and used as a fat substitute in the processing of cookies. The preparation process of Amomum villosum Lour. extract (AVE) was optimized based on antioxidant activity and yield firstly. Then, the AVE, ovalbumin, chitosan, and xanthan gum were used as raw materials to prepare a composite Pickering emulsion oleogel. The results showed that when the concentration of AVE, chitosan, and XG were 0.1%, 2.5%, and 0.3%, respectively, a stable and uniformly distributed Pickering emulsion oleogel was formed. In this case, the particle size of the composite oleogel was relatively small; the absolute value of zeta potential was higher; the microstructure was more stable, with less aggregation and flocculation; and the thermal stability and freeze–thaw stability were excellent. In addition, the addition of AVE enhanced the gel properties of the oleogel and had good solid-like properties, and strengthened the binding force, as well as the oxidation stability, making the whole system more stable. In addition, the results of the application of the composite oleogel in the cookies showed that the AVE–ovalbumin/xanthan gum/chitosan Pickering emulsion oleogel had similar sensory and texture properties to the butter group. The addition of AVE can delay the crispness, cohesiveness, hardness, and the rate of malondialdehyde formation in cookies during storage. In conclusion, the AVE–ovalbumin/xanthan gum/chitosan Pickering emulsion oleogel had good physicochemical stability and showed great potential in replacing saturated fat (butter) in baking products (cookies). Full article

The coagulation and flocculation properties of chitosan, an organic biopolymer derived from chitin, have been researched as an alternative to synthetic polymers and inorganic metal salt coagulants currently used in water and wastewater treatment. In an effort to encourage further research into the practical uses of chitosan as green chemistry in water and wastewater treatment and to promote the efficacious removal of microbial contaminants in drinking and wastewater, we have summarized the current state of research pertaining to the treatment of microorganisms in water and wastewater. A search of PubMed revealed 720 possible titles and abstracts, of which 44 full-text articles were identified as matching the eligibility criteria for inclusion in this systematic review. Results are presented based on the type of water matrix treated (i.e., drinking water, wastewater, and recreational waters) and a summary table providing details on the types and forms of chitosan utilized and the treatment mechanisms and processes described in the study. We find chitosan to be an effective coagulant, flocculant, and adsorbent for removing microbes from water and wastewater; some modified forms of chitosan can inactivate microbes and achieve disinfection, such as those containing metals like silver and antimicrobial chemicals like quaternary ammonium compounds or other strong oxidants, and use with filtration or electrochemical processes can achieve extensive reductions in microbes to meet performance targets of the World Health Organization. Full article

The present study was focused on the preparation, characterization and application onto cotton fabrics of different topical oil-in-water emulsions based on chitosan, eugenol and copaiba essential oil for potential topical applications. Different amounts of copaiba essential oil (oil phases) and eugenol were used, while the water phase consisted of hamamelis water. The designed formulations were evaluated via optical microscopy and rheological parameters assessment. The textile materials treated with the developed emulsions were analyzed in terms of antibacterial efficiency and in vitro and in vivo biocompatibility. The rheological measurements have shown that the emulsions’ stability was dependent on their viscosity and structure of the colloidal systems. The emulsions remained stable at temperatures equal to or below 35 °C, but an increase in temperature led to droplet flocculation and creaming. The emulsion-treated textiles exhibited antibacterial activity against Escherichia coli and Staphylococcus aureus, and in vivo biocompatibility on the skin of guinea pigs without sensitization effects. Our study revealed that eugenol and copaiba essential oil-based emulsions loaded on cotton textile materials could be promising candidates for developing skin-friendly textiles designed for different topical applications. Full article

Coagulation/Flocculation (C/F) process aims to efficiently eliminate turbidity, TSS, COD, BOD, toxic metals, phosphates, and UV_254nm from wastewater. Both natural and synthetic coagulants, used alone or in conjunction with flocculants, play crucial roles in this treatment. This review summarizes recent trends in coagulants for wastewater treatment, highlighting a wide array of inorganic and organic coagulants that have demonstrated significant efficacy based on reviewed studies. Notably, Crab Shell Bio-Coagulant (CS) excels in turbidity remov5al, achieving a remarkable 98.91% removal rate, while oak leaves protein shows superior performance in TSS and COD removal. Synthetic inorganic coagulants like PALS, PSiFAC_1.5:10:15, and PAPEFAC_1.5-10-15 demonstrate outstanding turbidity removal rates, over 96%. POFC-2 coagulant stands out for efficiently removing TSS and COD from domestic wastewater, achieving up to 93% removal for TSS and 89% for COD. Moreover, the utilization of FeCl₃ as an inorganic coagulant alongside chitosan as an organic flocculant shows promise in reducing turbidity, COD, and polyphenols in wastewater from vegetable oil refineries. PE-2, a novel organic coagulant, demonstrates exceptional efficacy in eliminating turbidity, TSS, COD, and BOD from sugar industry wastewater. Chitosan shows effectiveness in removing TOC and orthophosphates in brewery wastewater. Additionally, CTAB shows high efficiency in removing various toxic metal ions from wastewater. The hybrid coagulants: PAAP_0.1,0.5 and PPAZF accomplish exceptional turbidity removal rates, approximately 98%. Full article

In order to remove high-concentration emulsified oil from wastewater, a chitosan-based magnetic flocculant, denoted as FS@CTS-P(AM-DMC), was employed in this present study. The effects of factors including the magnetic flocculant dose, pH values, and coexisting ions were investigated. A comparative dosing mode with the assistance of polyacrylamide (PAM) was also included. The evolution of floc size was studied using microscopic observation to investigate the properties of flocs under different pH values and dosing modes. Particle image velocimetry (PIV) and extended Deryaguin–Landau–Verwey–Overbeek models were utilized to illustrate the distribution and velocity magnitude of the particle flow fields and to delve into the mechanism of magnetic flocculation. The results showed that FS@CTS-P(AM-DMC) achieved values of 96.4 and 74.5% for both turbidity and COD removal for 3000 mg/L of simulated emulsified oil. In the presence of PAM, the turbidity and COD removal reached 95.7 and 71.6%. In addition, FS@CTS-P(AM-DMC) demonstrated remarkable recycling and reusability performances, maintaining effective removal after eight cycles. The strength and recovery factors of magnetic flocs without PAM reached 69.3 and 76.8%, respectively. However, with the addition of PAM, they decreased to 46.73 and 51.47%, respectively. During the magnetophoretic processes, FS@CTS-P(AM-DMC) and oil droplets continuously collided and aggregated, forming three-dimensional network aggregates. Moreover, the magnetic floc generated a swirling motion, and the residual emulsified oil droplets could be further captured. Emulsified oil droplets were primarily removed through charge neutralization under acidic conditions. Under neutral and alkaline conditions, magnetic interactions played a major role in magnetic flocculation. Full article

Bioflocculants can be used for cost-effective harvesting of microalgae biomass on an industrial scale. This study investigates the flocculation-based harvesting approach to recovering Chlorella vulgaris microalgae biomass using chitosan biopolymer. Response surface methodology (RSM) was used to design the experiments and optimize the critical operating parameters. Box-Behnken Design (BBD) was employed at three levels, and 17 experimental runs were conducted to determine the optimal conditions and the relationship between operating parameters. The highest biomass recovery of 99.10% was achieved at the following optimized conditions: pH of 5, flocculation time of 45 min, and chitosan concentration of 10 mg/L. Both experimental results and model outputs indicated that pH significantly impacts microalgae harvesting and that process performance is less dependent on chitosan concentration and flocculation time. The quadratic model has shown the best fit with the experimental results. The results could be applied to large-scale microalgae harvesting applications to promote microalgae biomass recovery and reduce operating costs. Full article

The present study aimed to investigate the potential application of chitosan (CS) and its two derivatives, dialdehyde chitosan (DCT) and carboxymethyl chitosan (CMC), as new flocculants in the purification of filter backwash water. The main objective of the work was to remove the disadvantages and inconveniences associated with using synthetic flocculants, mainly based on polyacrylamide, by using biodegradable and non-toxic biopolymer flocculants. The chitosan derivatives were obtained in the process of the chemical modification of this polysaccharide. CS was oxidated with periodate in acetic acid solution to obtain DCT with a degree of substitution (DS) of 44.29%. For the CMC synthesis, after the alkaline activation of chitosan, the solution was treated with monochloroacetic acid (MCA) at 60 °C for 3 h, leading to carboxymethylated chitosan formation with a DS of 49.55%. Characterizations of the flocculants using Fourier transform infrared (FT-IR) spectroscopy, ¹³C nuclear magnetic resonance (¹³C NMR) spectroscopy, and an elementary analysis confirmed the successful modification of the chitosan. The morphology and thermal stability of the samples were investigated using scanning electron microscopy (SEM) and a thermogravimetric analysis (TGA), respectively. Moreover, the biopolymer materials were studied in a series of flocculation jar tests for filter backwash water samples collected at a water treatment plant (WTP) in Kutno, Poland. CMC turned out to be a particularly effective agent in an optimal amount of 0.2 mg/L, achieving nearly 99% iron removal and 98.26% turbidity removal efficiency rates, which indicates that chitosan–based materials can be ecological alternatives for polyacrylamide flocculants, effectively removing the impurities of iron ions. Full article