Fabrication of MoS2 restrained magnetic chitosan polysaccharide composite for the photocatalytic degradation of organic dyes.

Chitosan (CS) polysaccharide is expected to exhibit greater ionic conductivity, which can be attributed to its increased amino group content when it is blended with different semiconducting materials. Herein, the work used this conducting ability of chitosan and prepared a heterogeneous MoS2-induced magnetic chitosan (MF@CS) composite via the co-precipitation method, which was used to scrutinize the catalytic performance with Methylene Blue (MB) and Malachite Green (MG) dyes by visible light irradiation. The saturation magnetization value of the MF@CS composite is found to be 7.8 emu/g, which is less when compared to that of pristine Fe3O4 (55.7 emu/g) particles. The bandgap of the MF@CS composite is âˆ¼ 2.17eV, which exceeds the bandgap (Eg) of bare MoS2 of 1.80 eV. The maximum color removal of 96.3 % and 93.4 % for MB and MG dyestuffs is recognized in the exposure of the visible spectrum, respectively. At a starting dye dosage of 30 mg/L, 0.1 g/L of MF@CS, a pH level of 8-11, and 70 min of contact with direct light. The photocatalyst provides extremely good durability for a maximum of five phases. Hence, the MF@CS matrix is a viable and appropriate substance for the efficient treatment of effluents containing dye molecules.

Construction of ternary (1D/2D/3D) Fe2O3-supported micro pillared Cu-based MOF on chitosan with improved photocatalytic behavior on removal of paraquat.

A hetero-structured metal organic framework of Cu-BTC and Fe2O3 nano-photocatalyst were tethered over chitosan using the hydrothermal method and fabricated a hybrid porous nanocomposite (CS-Fe@Cu-BTC). X-ray diffractometer results exposed the existence of Fe2O3 peaks. Surface area measurements using BET showed a mesoporous structure and the formation of type IV adsorption isotherm for nanocomposite. XPS and SEM-EDAX confirmed the existence of Fe2O3 nanoparticles in the hybrid porous structure. The UV-vis diffuse reflectance absorption shape emphasized the role of Fe2O3 in enhancing the band gap of CS-Fe@Cu-BTC nanohybrid. The lower intensity photoluminescence spectra of the CS-Fe@Cu-BTC shows a competent charge partition and delayed the recombination of electron-hole pairs. The photo-mineralization efficiency of Cu-BTC and CS-Fe@Cu-BTC was evaluated in terms of electronic interactions using paraquat (PQT) as the probe molecule, which shows a mineralization of 91% at the pH range of ~ 5. The contribution of •OH in the degradation of PQT over CS-Fe@Cu-BTC nanocomposites revealed using the trapping test and the degradation mechanism follows the Langmuir-Hinshelwood model and pseudo-first-order kinetics. The durability of the CS-Fe@Cu-BTC nanocomposite was also established after four cycling processes.

Applications of chitin and chitosan based biomaterials for the adsorptive removal of textile dyes from water - A comprehensive review.

The presence of pollutants in the water bodies deteriorate the water quality and make it unfit for use. From an environmental perspective, it is essential to develop new technologies for the wastewater treatment and recycling of dye contaminated water. The surface modified chitin and chitosan biopolymeric composites based adsorbents, have an important role in the toxic organic dyes from removal wastewater. The surface modification of biopolymers with various organics and inorganics produces more active sites at the surface of the adsorbent, which enhances dye and adsorbent interaction more reliable. Herein, the work brought in the thought of the application of various chitin and chitosan composites in wastewater remediation and suggested the versatility in composites for the development of rapid, selective and effective removal processes for the detoxification of a variety of organic dyes. It further emphasizes the existing obstruction and impending prediction for the deprivation of dyes via adsorption techniques.

Photocatalytic performance of chitosan tethered magnetic Fe2O3-like (3D/2D) hybrid for the dynamic removal of anionic dyes: Degradation and mechanistic pathways.

Efficient photocatalysis methods with a production of less number of toxic intermediates are extremely advantageous for water decontamination. The degradation efficiency, specific surface area, stability and porosity will be improving by wrapping of Fe2O3 using appropriate biopolymers. In this work, Fe2O3 reinforced chitosan (Fe2O3@CS) nanocomposite was fabricated using co-precipitation method. The chitosan makes available its surface for the useful generation of the nanocomposite. These wrapping of Fe2O3 on chitosan provides synergistically improved properties that could be attributed to the elevated partition efficiency and faster transfer of the photo-generated charge carriers, which was substantiated by the experimental outcomes from photoluminescence and ESR spectroscopy. The results obtained from DRS analysis entail the reduction in band gap of Fe2O3@CS (2.52 eV) as compared with 3.52 eV of Fe2O3. The results indicated that 89.2% and 94.6% were the maximum degradations correspondingly for MO and OG. The trapping investigation emphasized the involvement of OH radicals in the degradation of dyes over Fe2O3@CS composites. The five cycles of regeneration experiment recommended the superior photostability of the fabricated Fe2O3@CS composite. This work proposed a practical arrangement and subsequent influence of an advanced photocatalyst for the useful remediation dyes from contaminated water without causing any secondary pollution.

Immobilization of MIL-88(Fe) anchored TiO2-chitosan(2D/2D) hybrid nanocomposite for the degradation of organophosphate pesticide: Characterization, mechanism and degradation intermediates.

In this study, we have rationally designed and grafted a bio-assisted 2D/2D TiO2/MIL-88(Fe) (TCS@MOF) heterojunction by growing granular TiO2 on the surface of MIL-88(Fe) nanosheet, as hybrid photocatalyst. The hierarchical TCS@MOF composite was prepared via the one-pot solvothermal process and employed for monocrotophos (MCP) degradation under visible light region, since its persistent nature on soil and water causes major threat to the environment. The TCS@MOF promotes a number of packed high-speed nano-tunnels in the (p-n) heterojunctions, which significantly enhance the migration of photo-induced electrons (e-) and holes (h+), respectively and thus limits the charge recombination of e-s. The optimized photocatalyst achieves significant catalytic activity of ~98.79% for the degradation of MCP within 30 min of irradiation. The prominent oxidative radicals namely •OH, •O2- etc., were involved in the oxidation of organic pesticide. Besides, TCS@MOF exhibits outstanding stability even after five repetitive cycles for the oxidation of MCP with a negligible decrease in photo-activity. The proposed mechanism and oxidative pathways of MCP were rationally deduced in detail subject to experimental results. The mechanism renders insight into the oxidation and consequent bond rupture of pollutant as well as into the formation of products such as H2O, CO2, etc. This report unveils a novel architecture of proficiently optimized TCS@MOF material structure for the perceptive oxidation of organic contaminants.