Decolorization Efficiency Research Articles

Decolorization of Rhodamine B by the white rot fungus Coriolopsis caperata isolated from Central Kalimantan Forest

The decolorization of rhodamine B was examined using the white rot fungus Coriolopsis caperata, which was isolated from the Peat Swamp Forest at CIMTROP in Sebangau, Central Kalimantan. The experiments were carried out with varying concentrations of dye (10-100 mg/L) and incubation times (2-16 days) in a modified glucose-peptone medium. During the decolorization process, the enzyme activity of laccase (EC 1.10.3.2) was monitored. The findings revealed a clear link between enzyme activity and decolorization efficiency of C. caperata. The ideal conditions for fungal laccase synthesis and decolorization occurred at a dye concentration of 60 mg/L and were achieved for 12 days. These findings suggest that the white rot fungus C. caperata, isolated from the Central Kalimantan Forest could be developed into a novel bioremediation strategy for synthetic dyes.

Characterization of a Metanil Yellow-decolorizing Pseudomonas strain Isolated from the Juru Industrial Park

This study examines how the initial concentration of dye, temperature, pH, and NaCl content affect the ability of a bacterial strain, specifically identified as Pseudomonas sp. strain UPM291, to remove color from Metanil Yellow. The decolorization percentage exhibited a distinct trend throughout a range of dye concentrations (0-700 mg/L), with the greatest efficacy (90-100%) recorded at values below 200 mg/L. The efficiency declined at higher concentrations, reaching approximately 20% at a dosage of 700 mg/L. Temperature investigations unveiled a symmetrical curve resembling a bell shape, indicating a range of temperatures that is most favorable for the process of decolorization. The maximum efficiency, approaching 100%, was found at a temperature of 35°C. However, the efficiency decreased considerably as the temperature above 35°C, reaching approximately 20% at 50°C. The impact of pH on decolorization exhibited comparable patterns, with optimal efficacy observed at pH 6.5 and diminished efficacy at both more acidic and more alkaline settings. The decolorization efficiency reached its peak (90-100%) at a pH of 6.5 and decreased to approximately 60% at a pH of 8.0. The influence of the NaCl content on decolorization was shown to follow a certain pattern, with the most effective decolorization (90-100%) occurring at NaCl concentrations of up to 10 g/L. The efficiency declined as the NaCl concentrations increased, reaching around 20% at 30 g/L. The data indicate that the bacterial strain demonstrates the highest effectiveness in removing color within particular ranges of dye concentration, temperature, pH, and NaCl content. There is a noticeable decline in efficiency when the parameters go outside of these optimal ranges. Gaining a comprehensive understanding of these characteristics can assist in optimizing the conditions necessary for the efficient bioremediation of Metanil Yellow utilizing specific bacterial strains.

Chitosan anchored nZVI bionanocomposites for treatment of textile wastewater: Optimization, mechanism, and phytotoxic assessment

In recent years, there has been a growing focus on treating textile wastewater due to its escalating threat to aquatic ecosystems and exposed communities. The present study investigates the adsorption efficacy of biopolymer functionalized nanoscale zero-valent iron (CS@nZVI) composite for the treatment of textile wastewater using the RSM-CCD model. The structure and morphology of CS@nZVI were characterized using XRD, FTIR, FESEM, and EDX. CS@nZVI was then evaluated for its adsorption potential in removing COD, color, and other physico-chemical parameters from textile wastewater. The results showed the high efficacy of CS@nZVI for COD and color removal from textile wastewater. Under optimal conditions (pH 6, contact time 60 min, and 1.84 g CS@nZVI), COD removal reached a maximum of 85.53%, and decolorization efficiency was found to be 89.73%. The coefficient of determination R2 (0.98) and AIC (269.75) values suggested quadratic model as the best-fitted model for optimizing the process parameters for COD removal. Additionally, the physico-chemical parameters were found to be within permissible limits after treatment with CS@nZVI. The influence of coexisting ions on COD removal followed the order PO43− > SO42− > Cl− >Na+ > Ca2+. The kinetics data fitted well with the pseudo-first-order reaction, indicating physisorption as the primary mechanism. The thermodynamic study revealed the endothermic nature of the removal process. Reusability tests demonstrated that great regeneration capacity of spent CS@nZVIafter five consecutive cycles. Furthermore, toxicological studies showed reduced toxicity in treated samples, leading to improved growth of Vigna radiata L. These findings suggest that CS@nZVI bionanocomposites could serve as an efficient, cost-effective, and eco-friendly remediation agent for the treatment of textile effluents, presenting significant prospects for commercial applications.

One-Factor-at-a-Time (OFAT) Optimization of Victoria Blue R Dye Biodegradation by Pineapple Waste Garbage Enzymes

Victoria blue R is a cationic triphenylmethane dye usually released from textile industries and reported to exhibit mutagenic and carcinogenic effects on aquatic organisms and humans. Hence, the objective of this study is to investigate the capability of pineapple waste garbage enzymes to biodegrade the Victoria blue R dye using One-Factor-At-a-Time (OFAT) optimization under the effect of Victoria blue R dye concentration (0.02 to 0.10 mg/mL), pH (1 to 7), and temperature (25°C to 49°C) via Design Expert 7.0 software. The results show that pineapple waste garbage enzymes gave the highest decolorization efficiency at a concentration of 0.07 mg/mL of Victoria blue R dye, pH 4.74, and 40.4°C. The ANOVA analysis suggests all models are quadratic, and the R-Squared values for the factors are 0.92, 0.95 and 0.92 for the concentration of Victoria blue R dye, pH and temperature, respectively. This work proposed that pineapple waste garbage enzymes can effectively remove Victoria blue R dye in wastewater applications.

Novel biocomposite (Starch/metal–organic framework /Graphene oxide): Synthesis, characterization and visible light assisted dye degradation

Herein a new efficient biocomposites containing Starch metal–organic framework (MIL88A) and graphene oxide (Starch/MIL88A/GO) with different amounts of starch (0.05 0.1 and 0.2 g denoted as SMGO-0.5 SMGO-1 and SMGO-2) was synthesized characterized and used to degrade Acid Blue 92 (AB92). Decolorization efficiency was 7.4 % for Starch 19.4 % for GO 86 % for MIL88A and 90–98.5 % for Starch/MIL88A/GO composites (90 % for SMGO-0.5 96 % for SMGO-1 and 98.5 % for SMGO-2) using visible light. SMGO-2 composite showed the highest degradation ability. The effect of catalyst dosage and contaminant concentration on decolorization percentage was investigated. The efficiency of photocatalytic decolorization using 0 4 6 8 and 10 mg of Starch/MIL88A/GO are as follow: 10 55 89 93 and 98.5 % respectively. The results indicate that the decolorization by Starch/MIL88A/GO decreases as the initial pollutant concentration increases. Different decolorization kinetics (zero-order first-order and second-order) were studied. The reaction followed the zero-order kinetics. The zero-order decolorization rate constant for 0 4 6 8 and 10 mg of Starch/MIL88A/GO were 0.0134 0.1086 0.1182 0.1308 and 0.1727 respectively. The Starch/MIL88A/GO had high reusability (95 % after five cycles). The results indicated that the synthesized biocomposite (Starch/MIL88A/GO) could be used as an efficient photocatalyst to remove dye from the colored wastewater.

Efficient decolorization of reactive dyed cotton fabric with a two-step NaOH/Na2S2O4 process

Efficient decolorization of reactive dyed cotton fabric with a two-step NaOH/Na2S2O4 process

E-beam irradiation-induced synthesis of hydroxyethyl cellulose/(Cu2O-rGO)/BiVO4-based nanocomposite for photocatalytic remediation of wastewater under visible light

Using E-beam irradiation as an eco-friendly technique for initiation and crosslinking, a series of Hydroxyethyl Cellulose-poly vinyl alcohol copolymer hydrogels were synthesized as templates for cuprous oxide (Cu2O), reduced graphene oxide (rGO) and bismuth vanadate (BiVO4) nanoparticles to be used as nanocomposites photocatalysts for methylene blue (MB) dye decolorization using visible light. Preparation conditions were optimized to ensure the construction of a good network architecture and therefore the highest gelation degree. For the preparation of (Cu2O@rGO)/BiVO4 nanocomposites, a series of rGO was decorated by Cu2O using the precipitation method, followed by mixing with BiVO4 which was synthesized hydrothermally. (EDX), (XRD), (TEM), and (SEM) were used for nanoparticle characterization. The thermal characteristics of the fabricated nanocomposites were evaluated using thermal gravimetric analysis. The presence of rGO enhanced the decolorization efficiency of MB about 20 % higher than that of (HEC-PVA)/Cu2O which achieves only (59 %) decolorization efficiency. After the addition of BiVO4 NPs, the decolorization efficiency increased to reach 90 % after 150 min at pH 11 using a 10 ppm MB solution. The developed (HEC-PVA)/(Cu2O@rGO)/BiVO4 photocatalyst exhibits efficient reusability for 5 cycles. Treated dyed water shows a germination index (GI) of 82 % suggesting its suitability for irrigation of playgrounds and gardens.

Fabrication of coconut shell activated carbon filter system for removal of colour and pollutants in textile dye effluent

The present study evaluates the Decolorization and pollutant removal efficiency of chemically impregnated coconut shell-activated carbon using textile dye effluent in the filtration system. The coconut shell zinc chloride activated carbon (CSZAC) was used as a filtering media in wastewater treatment due to its wider pore space with better surface area (590.80 m2 g−1) and higher adsorption capacity. The SEM micrograph revealed that the activated carbon had networks of parallel running pores with internal microstructure and more active sites. The designed activated carbon filter system has dimensions of 90 x 60 x 30 cm; the sections included are the holding tank (50 liters capacity), filtration tank and storage tank with the optimized flow rate of 5 x 10−4 m3 min−1. The Color, pH, EC, TDS, TSS, BOD and COD of textile dyeing wastewater were significantly reduced, after the treatment through the CSZAC filtration system. The initial color concentration of textile dye effluent was 7021 HU and after treatment, the color was fully reduced and became colorless. CSZAC treatment reduced the BOD from 600 mg L−1 to 89.7 mg L−1 (80.6 per cent) and COD from 2500 mg L−1 to 205 mg L−1 (90.5 per cent). Therefore, CSZAC can be used as an effective adsorbent material to remove different dye compounds and pollutants from textile wastewater.

Ultrafiltration associated with microporous resin decolorizing the Bacillus subtilis fermentation broth for the production of γ-polyglutamic acid

Abstract Currently, the industrial production of γ-polyglutamic acid (γ-PGA) was mainly based on microbial fermentation, but the decolorization technology still needs to be improved. Therefore, in this study, the optimal decolorization conditions and efficiencies were investigated. As the result, D4006 was an ideal resin for the decolorization of γ-PGA fermentation broth. The optimal decolorization pH value and temperature were pH 3 and 40 °C, respectively; ultrafiltration differential pressure, temperature and time were 0.2 MPa, 40 °C, and 6 h, respectively. Moreover, the combination of D4006 (3 %) resin on the basis of ultrafiltration had a better decolorization effect on γ-PGA fermentation broth, and the decolorization rate reached 96.8 %.

Polymeric membrane with nanohybrids of Cu nanocomposites and metalloporphyrin-based nanosheets for enzyme-like catalytic degradation of Congo Red

Metalloporphyrin-based nanozymes are effective peroxidase-like catalysts for dye degradation; however, their reusability is a challenge due to the nanoscale dimensions. Membrane technology has the advantages of high efficiency, low energy consumption, and easy operation. Here, we integrate poly (vinylidene fluoride) (PVDF) membrane with nanozyme for effective decolorization of Congo Red (CR). A nanozyme (Cu@Cu-FeTCPP) is prepared by growth of copper hydroxide-copper oxide (Cu(OH)2-CuO) nanocomposites onto the metal organic framework (MOF) nanosheet consisting of tetrakis-(4-carboxyphenyl)-porphyrin iron ligands and cupric ion nodes. The functional membrane is achieved by loading Cu@Cu-FeTCPP nanozyme on the PVDF membrane surface (Cu@Cu-FeTCPP/PVDF). The as-prepared membrane shows catalytic activity for the degradation of CR. Under flow through conditions, the catalytic degradation in tangential flow plays a major role in overall decolorization of CR, far exceeding the contribution of adsorption. The membrane can rapidly catalyze the dye degradation even at different operating pressures (0.1–0.7 kPa) and feed solutions with higher CR concentrations (eg. 60 mg·L-1). Compared with the static batch catalysis and the free nanozyme catalysis, the membrane exhibits higher decolorization efficiency and outstanding reusability in the continuous flow process owing to the promoted mass transfer. After 40 min of continuous flow reaction in a feed solution containing CR (40 mg·L-1) and H2O2 (50 mM), the decolorization efficiency approaches 90% and remains above 85% after five catalytic cycles. The membrane with enzyme-mimicking ability has application prospect in wastewater treatment.

Potential of nickel oxide catalyst from banana peel extract via green synthesis method in both photocatalytic reduction of methylene blue and generation of hydrogen from sodium borohydride hydrolysis

In the present work, nickel oxide (NiO) catalyst was prepared using banana peel extract as a stabilizing agent via the green synthesis method. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX), X-ray diffraction (XRD), transmission electron microscopy (TEM) and ultraviolet spectroscopy (UV) analyses were carried out to investigate the structural and textural characteristics of the NiO catalyst. According to the XRD and TEM results, the particle size of the NiO catalyst was found to be in the range of 20–80 nm. From the EDX analysis, it was concluded that the NiO catalyst was synthesised in pure form. The potential of the NiO catalyst was tested for the first time in both the photocatalytic reduction of methylene blue (MB) and the generation of hydrogen (H2) from sodium borohydride (NaBH4) hydrolysis. A high decolorization efficiency of 98.09 % and a reuse efficiency of 90.89 % after five recycles were achieved for the photocatalytic reduction of MB using NiO catalyst. The photocatalytic reduction of MB was consistent with the pseudo-first order kinetic model, and the reaction rate constant was found to be 2.55 min−1. The H2 generation rate (RH2) of 922.5 mLH2 min−1 gcat−1 at 70 °C was achieved for the NaBH4 hydrolysis. The kinetics of H2 generation from NaBH4 hydrolysis was studied employing the nth-order and the Langmuir-Hinshelwood models, and the activation energy (Ea) values were found to be 21.29 kJ mol−1 and 22.23 kJ mol−1, respectively. It was concluded that the NiO catalyst prepared by the eco-friendly green synthesis method has a promising potential in both photocatalytic reduction of MB and H2 generation from NaBH4 hydrolysis.

Activation of peroxymonosulfate by CoFe2O4 layered catalyst derived from steel pickling sludge for the decolorization of tartrazine solution

Steel pickling sludge provides abundant iron resource for the preparation of bimetallic catalyst used in heterogeneous advanced oxidation processes (AOPs). In this study, steel pickling sludge was used to synthesize CoFe2O4 layered catalyst through a convenient one-step solvothermal reaction and applied as a powerful peroxymonosulfate (PMS) activator to decolorize tartrazine solution. The layered microstructure, composition, and structure of the as-prepared CoFe2O4 catalyst were characterized by scanning electron microscope, X-ray photoelectron spectroscopy, and X-ray diffraction. The influences of catalyst dosage, PMS dosage, and initial solution pH on the decolorization efficiency were systematic investigated and optimized, the results showed that CoFe2O4 layered catalyst exhibited excellent catalytic effect with 96% decolorization efficiency in 15 min. SO42−, Cl−, and NO3− had little effect on the decolorization efficiencies compared to HCO3− and CO32−. Both free radicals (∙SO4−, ∙OH, and ∙O2−) and non-radicals (1O2 and mediated electron transfer) pathways coexist in CoFe2O4 layered catalyst/PMS system, and ∙SO4− was the dominate reactive oxygen species. Based on DFT calculation, the plausible decolorization mechanism of tartrazine in CoFe2O4 layered catalyst/PMS system could be well elucidated. This study offers an economic reuse strategy to convert the “steel pickling waste sludge” to low-cost and higher-value bimetallic catalyst for the practical application in AOPs.

Decolorization of corn syrup in a dynamic system by activated carbon bed: Microwave-assisted impregnation of H3PO4 over cherry and date stones for efficient purification

The growing market of light corn syrup poses the requirement for the rapid decolorization of dark liquor, needing the design of an effective dynamic adsorption system without blockage of liquid flow. Therefore, the shaped adsorbents such as granular, and rod like activated carbon with the relative strong mechanical strength should be fabricated from the inexpensive resources. In the current work, a sustainable green method was proposed to produce the shaped activated carbon from the cherry, and date stones via the facile, and fast microwave-assisted technique. Different contents of phosphoric acid were impregnated over the stones under the microwave irradiation, 200–1000 W. Then, the impregnated stones were carbonized at 500–900 °C, within 15–75 min to identify the proper conditions for the fabrication of beds with the maximal efficiency in the dynamic decolorization of corn syrup, 78 mL min−1. The obtained results clearly showed that the granular activated carbon produced from the cherry stone is effective than that fabricated from the date stone. It is anticipated that the presented platform holds the great promises to eliminate the colorant components from the corn syrup due to development of micro, and mesopores, 2.0–4.2 nm, in bed, providing a surface area about 455 m2 g−1.

Enhanced photocatalytic activity of CeO2 and magnetic biochar-CeO2 nanocomposite prepared from Murraya koenigii stem for degradation of methyl orange under UV light

This paper discusses the synthesis and characterization of CeO2 nanoparticles (NPs), magnetic biochar-CeO2 (MBC-CeO2) nanocomposites (NCs), and their photocatalytic analysis in methyl orange (MO) degradation. MBC-CeO2 material is synthesized on the basis of carbonization of iron oxide precursor treated with Murraya koenigii (curry leaf) stem powder. CeO2 with crystallite size 7.78 nm and MBC-CeO2 with crystallite size 14 nm are identified from XRD, with band gap energies 3.16 and 2.84 eV respectively. XPS, SEM, TEM, BET, UV–visible, FTIR, and PL characterizations are conducted to study the morphology, oxygen vacancy concentration in the samples. The removal efficiency of Methyl Orange (MO) is studied by changing both pH and concentration of MO solution. The decolorization of MO is observed at an optimum level of pH 4, with a catalyst dosage of 50 mg, which obeys pseudo-first-order kinetic theory. Under 16 min UV irradiation treatment, the decolorization efficiency of the as-prepared MBC-CeO2 is 96.7 % and total organic carbon (TOC) is ∼94 %, and for the as-prepared CeO2 it is 87.5 % and ∼ 81 % respectively. The plausible degradation pathway of MO is analyzed through LC-MS method. Regression studies are conducted to assess the suitability of all models towards photocatalytic degradation. The recycling experiment showed that both MBC-CeO2 and CeO2 are excellent stable catalysts for the activation of MO.

Improved Laccase Encapsulation in Copper-Doped Zeolitic Imidazolate Framework-8 for Reactive Black 5 Decolorization

As the largest group of synthetic dyes, azo dyes can pose various health and environmental risks due to their widespread use and challenging degradation. Laccases are efficient green biocatalysts for the degradation of organic pollutants. Herein, we report the in situ packaging of laccase in copper-doped zeolitic imidazolate framework-8 (ZIF-8) for the decolorization of reactive black 5, which is a model azo dye. The immobilization support (Cu5/mZIF-8) was obtained via lowering the precursor ratio of ZIF-8 and incorporating copper ions during the synthesis process. Cu5/mZIF-8 were found to be nanospheres with an average diameter of around 150 nm. Laccase encapsulated in Cu5/mZIF-8 showed an activity recovery of 75.6%, which was 2.2 times higher than that of the laccase embedded in ZIF-8. Meanwhile, the immobilized laccase (Lac@Cu5/mZIF-8) showed a higher catalytic activity in organic solvents than that of the free enzyme. In the presence of a mediator, Lac@Cu5/mZIF-8 could remove 95.7% of reactive black 5 in 40 min. After four consecutive cycles, the dye decolorization efficiency declined to 28%. About four transformation products of reactive black 5 were identified via LC-MS analysis, and the potential decolorization mechanism was proposed. The results indicated that the immobilized laccase could be used as an efficient biocatalyst in dye decolorization.

Production of high-value oxidative enzymes by Cyathus bulleri on agricultural and agri-food wastes for application in the textile sector.

Ligninolytic and other oxidative enzymes have emerged as promising biocatalysts in several industries. Since their production at a low cost is necessary for any large-scale application, we demonstrate the use of rice bran (RB), an agricultural waste and agri-food wastes such as potato peelings (PP), banana peelings (BP), and green pea peelings (GPP) for their production. High activity of laccase (12 U/ml), manganese peroxidase (16.11 ± 1.43 U/ml), and aryl alcohol oxidase (1.25 U/ml) was obtained on the PP on the 12th day of growth and ~ 6 U/ml of lytic polysaccharide monooxygenase was obtained on the 14th day of growth demonstrating PP to be a good substrate for their production. RB served as the next best substrate for the production of these enzymes. While the GPP was effective for the production of laccase (9.2 U/ml), this and the BP were not good substrates for the production of other enzymes. Efficient (48-82%) decolorization of several azo-, triarylmethane- dyes, and real textile effluent, without the addition of any mediator, demonstrated the high oxidative ability of the crude culture filtrate produced on the PP (CF-PP), which was a significant improvement compared to the treatment given by the previously reported culture filtrate obtained on wheat bran (CF-WB). An extensive breakdown of Reactive Orange (RO) 16 was demonstrated using CF-PP resulting in the formation of a new product at m/z of 294.05 (6-acetamido-3,4-dioxo-3,4-dihydronapthalene-2-sulfonate), previously reported to be produced on ozonation/advanced oxidation of RO16. The predominant laccase and manganese peroxidase isoforms produced on the PP were also identified.

Anaerobic biodegradation of azo dye reactive black 5 by a novel strain Shewanella sp. SR1: Pathway and mechanisms

The efficiency of microbial populations in degrading refractory pollutants and the impact of adverse environmental factors often presents challenges for the biological treatment of azo dyes. In this study, the genome analysis and azo dye Reactive Black 5 (RB5) degrading capability of a newly isolated strain, Shewanella sp. SR1, were investigated. By analyzing the genome, functional genes involved in dye degradation and mechanisms for adaptation to low-temperature and high-salinity conditions were identified in SR1. The addition of co-substrates, such as glucose and yeast extract, significantly enhanced RB5 decolorization efficiency, reaching up to 87.6%. Notably, SR1 demonstrated remarkable robustness towards a wide range of NaCl concentrations (1–30 g/L) and temperatures (10–30 °C), maintaining efficient decolorization and high biomass concentration. The metabolic pathways of RB5 degradation were deduced based on the metabolites and genes detected in the genome, in which the azo bond was first cleaved by FMN-dependent NADH-azoreductase and NAD(P)H-flavin reductase, followed by deamination, desulfonation, and hydroxylation mediated by various oxidoreductases. Importantly, the degradation metabolites exhibited reduced toxicity, as revealed by toxicity analysis. These findings highlighted the great potential of Shewanella sp. SR1 for bioremediation of wastewaters contaminated with azo dyes.

Physicochemical fabrication of chitosan and algae with crosslinking glyoxal for cationic dye removal: Insight into optimization, kinetics, isotherms, and adsorption mechanism

Herein, a highly efficient and sustainable adsorbent of cross-linked chitosan-glyoxal/algae biocomposite (CHT-GLX/ALG) adsorbent was developed through an innovative hydrothermal cross-linking method. The CHT-GLX/ALG biocomposite was characterized using several complementary analytical methods that include CHN-O, XRD, FTIR, SEM-EDX, and pHpzc. This new adsorbent, named CHT-GLX/ALG, was utilized for the adsorption of a cationic dye (methyl violet 2B; MV 2B), from synthetic wastewater. The optimization of the dye adsorption process involved key parameters is listed: CHT-GLX/ALG dosage (from 0.02 to 0.1 g/100 mL), pH (from 4 to 10), and contact time (from 20 to 180 min) that was conducted using the Box-Behnken design (BBD). The optimal adsorption conditions for the highest decolorization efficiency of MV 2B (97.02 %) were estimated using the statistical model of the Box-Behnken design. These conditions include a fixed adsorbent dosage of 0.099 g/100 mL, pH 9.9, and a 179.9 min contact time. The empirical data of MV 2B adsorption by CHT-GLX/ALG exhibited favorable agreement with the Freundlich isotherm model. The kinetic adsorption profile of MV 2B by CHT-GLX/ALG revealed a good fit with the pseudo-second-order model. The maximum adsorption capacity (qmax) for MV 2B by CHT-GLX/ALG was estimated at 110.8 mg/g. The adsorption of MV 2B onto the adsorbent can be attributed to several factors, including electrostatic interactions between the negatively charged surface of CHT-GLX/ALG and the MV 2B cation, as well as n-π and H-bonding. These interactions play a crucial role in facilitating the effective adsorption of MV 2B onto the biocomposite adsorbent. Generally, this study highlights the potential of CHT-GLX/ALG as an efficient and sustainable adsorbent for the effective removal of organic dyes.

Quaternary ammonium-functionalized rosin-derived resin for the high-performance capture of caramels: Experiments and quantum chemical theory simulations

Water contamination caused by discharge of spent washes containing colorants remains controversial. In this study, rosin-derived strongly basic macroporous anion-adsorption resin (RSBMAR) was designed as an advanced adsorbent for scavenging caramel, the most recalcitrant colorant in spent washes. Toxicity tests suggest that RSBMAR is environmentally friendly and hardly threatens aquatic organisms. RSBMAR exhibits outstanding caramel capture efficiency because of its rich target quaternary ammonium (−R4N+) and protonated tertiary amine (−R3NH+) groups, abundant porous structure, large specific surface area, excellent thermal stability, and good sphericity. The caramel adsorption capacity of RSBMAR was 165.86 mg/g and the decolorization efficiency reached 96.75%. After five cycles, the spent RSBMAR maintained a high decolorization rate, indicating excellent renewability. Multiple characterizations indicated that caramel capture was largely mediated by charge interaction between −R4N+/−R3NH+ (RSBMAR) and −RCOO−/−RCOOH (caramel), followed by H-bonds. Quantum chemical theory simulations, including electrostatic potential, local ionization energy, frontier molecular orbitals, and independent gradient model analyses, further visualized caramel capture mechanisms at atomic level. Hirshfeld surface analysis revealed that RSBMAR acts as both an H-bond donor and acceptor during caramel uptake. Dynamic adsorption was performed to treat real wastewater, laying the foundation for the industrial application of RSBMAR.

Screening of White-Rot Fungi Isolates for Decolorization of Pulp and Paper Mill Effluent and Assessment of Biodegradation and Biosorption Processes.

Ten white-rot fungal isolates were evaluated for the decolorization potential of pulp and paper mill effluent. Trametes elegans PP17-06, Pseudolagarobasidium sp. PP17-33, and Microporus sp.2 PP17-20 showed the highest decolorization efficiencies between 42 and 54% in 5 d. To reveal the mechanisms involved in decolorization and assess the long-term performance, PP17-06, which showed the highest decolorization efficiency, was further investigated. It could reduce the ADMI color scale by 63.6% in 10 d. However, extending the treatment period for more than 10 d did not significantly enhance the decolorization efficiencies. The maximum MnP activity of 3.27 U L-1 was observed on the 6 d during the biodegradation. In comparison, laccase activities were low with the maximum activity of 0.38 U L-1 (24 d). No significant LiP activities were monitored during the experiment. Dead fungal biomass showed an optimum decolorization efficiency of 44.18% in 8 d employing the biosorption mechanism. No significant changes in the decolorization efficiency were observed after that, suggesting the equilibrium status was reached. These results revealed that PP17-06 has the potential to decolorize pulp and paper mill effluent by employing both biodegradation and biosorption processes.