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The primary concern is the large amounts of emitted organic dyes through wastewater from numerous sectors. One of the most hazardous dyes commonly used in the industrial sector is methyl violet. It has been known to cause skin, gastric, and respiratory disorders. Therefore, a novel photocatalyst based on cobalt‑tin sulfide (Co 3 Sn 2 S 2 ) was prepared using the solvothermal process. The photocatalyst was supplemented with Chitosan to prepare the cobalt tin sulfide-chitosan composite (Co 3 Sn 2 S 2 /Chi) for the photocatalytic degradation of methyl violet dye. Based on EDX analysis, a definite ratio of tin, cobalt, and sulfide was found. The FTIR of Co 3 Sn 2 S 2 /Chi revealed the characteristic bands of chitosan and metal sulfide bonds. SEM results showed that the particle had an irregular shape. The composite's crystalline structure was identified by XRD analysis as being 56 nm in crystalline size. The photocatalyst had a narrow band gap of 1.02 eV. At ideal conditions, the developed photocatalyst demonstrated greater degradation efficiency of methyl violet dye under solar light irradiation. The photocatalyst successfully decomposed 95 % of the methyl violet dye (40 ppm) within 70 min, operating at a pH of 9.0. This remarkable degradation was achieved by employing 0.25 g of the photocatalyst. The photocatalyst is more appealing and can be reused for up to three successive cycles. The photocatalyst is well-suited for "pseudo-first-order kinetics" to decontaminate methyl violet dye. The novel photocatalyst showed the most robust ability to decolorize methyl violet when exposed to sunlight and was a viable substitute for dye detoxification of organic dyes from wastewater., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Nisar Ali reports financial support was provided by Huaiyin Institute of Technology School of Chemical Engineering. Nisar Ali reports a relationship with Huaiyin Institute of Technology that includes: employment. Nothing to declare If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Water scarcity has been a crucial debate in recent years regarding the critical scenario of water pollution. The water body is continuously contaminated by organic effluents of textile industries, including pigmented dye pollutants. To tackle water bodies contamination, there is a need to develop an eco-friendly and efficient method for removing toxic dyes. Herein, ternary metal selenide nanocomposites of barium nickel selenide (NBSe-NPs) were synthesized by the solvothermal method supported by chitosan microsphere (NBSe-NPs-CM). Recovery of the catalyst was convenient by capping nanoparticles in the microsphere to maintain effective stability, biocompatibility, and well-designed surface coating. FTIR spectrum verified nanocomposite synthesis and chitosan microsphere (NBSe-CM) formation. SEM observations of nanocomposites and NBSe-CM indicated an average size of 13.78 nm and 253 μm, respectively. The presence of barium, nickel, and selenium elements in the NBS-NPs was verified by EDX analysis. The nanocomposites had a crystallite size of 15.73 nm. The photocatalyst exhibited a narrow bandgap of only 1.3 eV based on Tauc's plot. In addition, the synthesized microsphere demonstrated an efficient photocatalytic degradation (97 %) of Bromothymol Blue dye within 100 min under optimized operating conditions (pH of 6.0, dye concentration of 40 ppm, catalyst dosage of 0.25 g). The photocatalysis process followed the pseudo-first-order kinetics. The repeatability studies showed a slight decline in the catalyst's efficiency after four successive cycles. The DFT study shows that the NBSe-CM is energetically stable with more considerable negative binding energy, and the dye molecule interacts more strongly with the NBSe-CM surface. The findings highlight the exceptional characteristics of the newly designed ternary-metal-selenide-containing chitosan-microspheres for degrading dye contaminants from textile effluents., Competing Interests: Declaration of competing interest Nisar Ali reports financial support was provided by A'Sharqiyah University College of Applied and Health Sciences. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Mercury emissions from the industrial sector have become an undeniable concern for researchers due to their toxic health effects. Efforts have been made to develop green, efficient, and reliable methods for removal of mercury from wastewater. Sorption process promises fruitful results for the decontamination of cations from wastewater. Among the number of used sorbents, metal sulfides have been emerged as an appropriate material for removing toxic metals that possess good affinity due to sulfur-based active sites for Hg through "Lewis's acid-based soft-soft interactions." Herein, nickel-sulfide nanoparticles were synthesized, followed by their incorporation in chitosan microspheres. FTIR analysis confirmed the synthesis of nickel sulfide-chitosan microspheres (NiS-CMs) displaying sharp bands for multiple functional groups. XRD analysis showed that the NiS-CMs possessed a crystallite size of 42.1 nm. SEM analysis indicated the size of NiS-CMs to be 950.71 μm based on SEM micrographs. The sorption of mercury was performed using the NiS-CMs, and the results were satisfactory, with a sorption capacity of 61 mg/g at the optimized conditions of pH 5.0, 80 ppm concentration, in 60 min at 25 °C. Isothermal models and kinetics studies revealed that the process followed pseudo-second-order kinetics and the Langmuir isothermal model best fitted to experimental data. It was concluded that the NiS-CMs have emerged as the best choice for removing toxic mercury ions with a positive impact on the environment., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The existence of heavy metals in ecological systems poses great threats to living organisms due to their toxicant and bio-accumulating properties. Mercury is a known toxicant with notable malignant impacts. It has long been known to cause toxic threats to the health of living organisms since the break out of Minamata disease. The turbulent expulsion of mercury-based pollutants from the industrial sector, requires a proper solution. Many attempts have been made to design a greener and more efficient route for a satisfactory removal of mercury. In the current study, bismuth sulfide nanoparticles (BiSNPs) have been synthesized via the co-precipitation method. The BiSNPs were supported with crosslinked chitosan to enhance their sorption capacity and avoid leaching. The average size of the BiSNPs was 42 nm based on SEM micrographs. The SEM analysis of the bismuth sulfide chitosan-crosslinked beads (BiS-CB) showed that the beads possessed a spherical and smooth morphology with a size of 1.02 mm. The FTIR analysis showed that the beads possessed the characteristics bands of imine groups of chitosan, bismuth, sulfur, and glycosidic linkages present in the molecules. The XRD analysis confirmed the phase crystallinity of the BiS-CB with an average crystallite size of 11 nm. The BiS-CB was employed for the sorption of mercury from water samples. The maximum sorption capacity of 65.51 mg/g was achieved at optimized conditions of pH 5, concentration 80 ppm, in 45 min at 30 °C. The mechanism studied for mercury removal showed that sorption followed the complexation mechanism according to the SHAB concept. In conclusion, the results showed that the BiS-CB sorbent exhibited an excellent sorption capacity to remove mercury., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Employing dyes in different industrial sectors has produced a serious threat to the environment and living organisms of water bodies and land. For the decontamination of such toxic dyes, efforts have been made to develop an efficient, feasible, and low maintenance processes. In this context, chitosan-zinc selenide (CS-ZnSe) nanoparticles were prepared through chemical reduction method as the efficient photocatalysts for the decontamination of toxic dyes through photocatalysis. Photocatalyst's synthesis was confirmed with the help of FTIR spectroscopy. XRD indicated the hexagonal crystal structure of the CS-ZnSe with a crystallite size of 12 nm. SEM micrographs showed the average nano photocatalyst size as 25 nm. EDX analysis was employed to determine the elemental composition of the CS-ZnSe. An excellent photocatalytic degradation efficiency for tartrazine and sunset yellow dyes was obtained using CS-ZnSe. The results showed a 98% and 97% degradation efficiency for tartrazine dye and sunset yellow (SY) dye at optimized conditions of time (3 h), pH (5), dye concentration (30 ppm), catalyst dosage (0.09 g and 0.01 g) , and at a temperature of 35 °C. Findings of the photocatalytic degradation process fitted well with first-order kinetics for both the dyes. Rate constant, 'K' value was found to be 0.001362 min -1 and 0.001257 min -1 for tartrazine and SY dyes, respectively. While value for (correlation coefficient, R 2 ) was 0.99307 and 0.99277 for tartrazine and sunset yellow dyes, respectively. Recyclability of the photocatalyst was confirmed using it for consecutive cycles to degrade organic dyes. Results showed that the CH-ZnS possesses excellent efficiency in decontaminating organic dyes from industrial wastewater., (Copyright © 2022 Elsevier Inc. All rights reserved.)

In this investigation, chitosan-coated nickel selenide nano-photocatalyst (CS-NiSe) was successfully prepared through the chemical reduction method. FTIR spectroscopy confirmed the synthesis of CS-NiSe nano-photocatalyst. Further, XRD analysis exhibited a monoclinic crystalline phase of photocatalyst with a crystallite size of 32 nm based on Scherer's equation. The SEM micrographs showed that the photocatalyst has an average particle size of 60 nm. The bandgap of CS-NiSe was (2.85 eV) in the visible region of the spectrum. Due to this reason, the CS-NiSe was applied under solar light illumination for the photocatalytic activity of Erythrosine and Allura red dyes. The CS-NiSe presented the highest degradation efficiency of 99.53% for Erythrosine dye in optimized experimental conditions of 100 min at 30 °C, 30 ppm concentration, pH 5.0, and 0.14 g catalyst dose. For Allura red dye, a high degradation of 96.12% was attained in 120 min at pH 4.0, 100 ppm initial dye concentration, 35 °C temperature, and 0.1 g catalyst dose. The CS-NiSe showed excellent degradation efficiency and reduced to (95% for Erythrosine and 91% for Allura red dye) after five consecutive batches. Moreover, the statistical and neural network modelling analysis showed the significant influence of all studied variables on dyes degradation performance. The results demonstrated that CS-NiSe exhibited excellent photocatalytic performances for Erythrosine and Allura red dyes and could be a better photocatalyst for removing these dyes from industrial effluents., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Organic dyes that are extensively released in wastewater from various industries remain the priority concern in the modern world. Therefore, a novel catalyst, bismuth-iron selenide, was prepared through the solvothermal process for photocatalytic degradation of a carcinogenic crystal violet dye. The catalyst was supported with chitosan to form iron-bismuth selenide-chitosan microspheres (BISe-CM). The synthesized catalyst was composed of iron, bismuth, and selenium in a definite proportion based on EDX analysis. FTIR analysis confirmed the synthesis of BISe-CM from characteristic bands of metal selenium bond as well as the typical bands of chitosan. SEM analysis illustrated the average diameter of the barren catalyst to be 54.8 nm, while the average size of the microspheres was 982.5 um. The BISe-CM has the surface of a pore with an average size of 0.5 um. XRD analysis revealed that the synthesized catalyst was composed of Fe 3 Se 4 and Bi 2 Se 3 . The prepared catalyst showed better degradation efficiency for crystal violet dye at optimized conditions under solar irradiation. Employing 0.2 g of BISe-CM resulted in complete degradation for 30 ppm of crystal violet dye in 150 min at pH 8.0. The reusability of the catalyst up to four consecutive times makes it a more attractive and practical candidate. Moreover, the catalyst followed pseudo-first-order kinetics in the decontamination of crystal violet. Conclusively, the novel photocatalyst showed the best decolorizing property of crystal violet under sunlight irradiation and could be a suitable alternative for dye decontamination from wastewater.

Herein, chitosan‑zinc sulfide nanoparticles (CS-ZnS-NPs) were developed as an efficient photocatalyst for the degradation of toxic dyes. The as-synthesized CS-ZnS-NPs were analyzed using XRD, FTIR, SEM, and EDS. The functional groups of CS-ZnS-NPs were validated with FTIR spectroscopy. The SEM envisaged the average particle size as 40 nm, whereas EDS interpreted the compositional analysis of the nanocomposite. XRD analysis illustrated the crystallinity and hexagonal crystal structure of the CS-ZnS-NPs. The photocatalytic efficiency of CS-ZnS-NPs was evaluated using two carcinogenic azo dyes, Acid Brown 98 and Acid Black 234. A UV lamp (254 nm) was used as an irradiation source during the photocatalytic degradation of dyes. At the optimum conditions, the synthesized CS-ZnS-NPs showed 96.7% degradation for Acid Black 234 in 100 min and 92.6% for Acid Brown 98 in 165 min. The degradation phenomena followed pseudo-first-order kinetics. The values of rate constant (k) were 0.01464 and 0.04096 min -1 with correlation coefficient (R 2 ) of 0.98891 and 0.99406 for Acid Brown 98 and Acid Black 234, respectively. The CS-ZnS-NPs were easily recovered and recycled for four successive batches. The results showed that CS-ZnS-NPs are considered as highly productive, cost-effective and promising photocatalyst in degrading pollutants in several consecutive cycles., Competing Interests: Declaration of competing interest The authors report no conflict of interest in any capacity, i.e., competing or financial., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The latency of toxic cations in the ecosystem poses serious ecological problems due to its bioaccumulation potential and toxicity to living organisms. The effective removal of these wastewater cations releasing from multi-industries is a bottleneck issue. Therefore, an attempt has been made to design a suitable sorbent for cations sorption from the aqueous environment. The chitosan biopolymer was modified with triethylenetetramine to incorporate active sites in the polymeric sequence to boost up its cations sorption capacity. Triethylenetetramine molecule anchoring chitosan (CH-TET) was authenticated through elemental assay, Fourier-transform infrared spectroscopy and 13 C NMR in solid-state, scanning electron microscopy and thermal analysis. The sorption of lead (1.94 mmol g -1 ), copper (2.79 mmol g -1 ) and nickel (1.53 mmol g -1 ) was carried out using the functionalized chitosan from aqueous solution, which showed higher sorption capacity for lead and copper than the pristine chitosan in terms of Langmuir sorption isotherm. To scrutinize the mechanism of sorption and energy of interaction between sorbent and sorbate, Langmuir, Temkin, and Freundlich isotherm models were used for sorption study. The Langmuir model showed the best fitting to the results based on lower error function values and a higher correlation coefficient (R 2 ). It can be concluded that the triethylenetetramine-modified chitosan might be considered as an effective sorbent for cations removal from industrial wastewater., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Herein, we report the development of chitosan (CH)-based bio-composite modified with acrylonitrile (AN) in the presence of carbon disulfide. The current work aimed to increase the Lewis basic centers on the polymeric backbone using single-step three-components (chitosan, carbon disulfide, and acrylonitrile) reaction. For a said purpose, the thiocarbamate moiety was attached to the pendant functional amine (NH 2 ) of chitosan. Both the pristine CH and modified CH-AN bio-composites were first characterized using numerous analytical and imaging techniques, including 13 C-NMR (solid-form), Fourier-transform infrared spectroscopy (FTIR), elemental investigation, thermogravimetric analysis, and scanning electron microscopy (SEM). Finally, the modified bio-composite (CH-AN) was deployed for the decontamination of cations from the aqueous media. The sorption ability of the CH-AN bio-composite was evaluated by applying it to lead and copper-containing aqueous solution. The chitosan-based CH-AN bio-composite exhibited greater sorption capacity for lead (2.54 mmol g -1 ) and copper (2.02 mmol g -1 ) than precursor chitosan from aqueous solution based on Langmuir sorption isotherm. The experimental findings fitted better to Langmuir model than Temkin and Freundlich isotherms using linear regression method. Different linearization of Langmuir model showed different error functions and isothermal parameters. The nonlinear regression analysis showed lower values of error functions as compared with linear regression analysis. The chitosan with thiocarbamate group is an outstanding material for the decontamination of toxic elements from the aqueous environment.

The present study reports the engineering of functionalized chitosan (CH)-based biosorbent material. Herein, a two-step reaction was performed to chemically modify the CH using 1,4-bis(3-aminopropyl) piperazine to incorporate nitrogen basic centers for cations sorption from the aqueous environment. The resultant functionalized chitosan-based sorbent material was designated as CH-ANP and characterized using various analytical techniques, including elemental analysis, Fourier-transform infrared spectroscopy (FTIR), 13C NMR (in solid-state), X-ray diffraction, and thermal analysis. Then, the newly engineered CH-ANP was employed for the removal of copper, lead, and cadmium in the aqueous medium. Langmuir sorption isotherm analysis revealed that the highest sorption abilities achieved were 2.82, 1.96, and 1.60 mmol g−1 for copper, cadmium, and lead, respectively. Linear and nonlinear regression methods were deployed on the sorption data to study the behavior of the Langmuir, the Freundlich, and the Temkin sorption isotherms. Among the four different forms, the Langmuir isotherm type 1 fit well to the experimental data as compared to the other models. It also showed the lowest values of error, and a higher correlation coefficient than the Freundlich and Temkin models; thus it was the best fit with the experimental data compared to the latter two models. In conclusion, the findings suggest that chemically modified novel materials with enhanced Lewis basic centers are useful and promising candidates for the sorption of various toxic cations in aqueous solution. [ABSTRACT FROM AUTHOR]

Herein, we report the development and characterization of a green sorbent material. For the said purpose, the chitosan's capacity of cation sorption was enhanced by incorporating thiocarabamate group, which ultimately increases active sites for attracting the cationic species. The process was carried out by utilizing acrylomorpholine, carbon disulfide and chitosan in a single stage process. The product (CH-ATC) acquired was well characterized with 13C NMR (solid-form), FTIR spectroscopy, elemental investigation, thermogravimetic analysis and scanning electron microscopy. The novel product's ability of sorption was evaluated by applying it to lead and copper solution. The modified chitosan (CH-ATC) exhibited greater sorption capacity of lead (1.58 mmol g−1) over raw chitosan when applied to aqueous solution based on Langmuir sorption isotherm. The new material also showed reasonable sorption capacity for copper (1.25 mmol g−1). The experimentally obtained results associated well to Langmuir model than Temkin and Freundlich isotherms using linear regression method. Different linearization of Langmuir model showed different error functions and isothermal parameters. The nonlinear regression analysis showed lower values of error functions as compared to linear regression analysis. The chitosan with thiocarbamate chain is outstanding material for selected cations decontamination form aqueous solution. [ABSTRACT FROM AUTHOR]