A novel bead synthesis of the Chiron-sodium dodecyl sulfate hydrogel and its kinetics-thermodynamics study of superb adsorption of alizarin red S from aqueous solution

Ultrasound-assisted formation of composite materials from fish scale waste hydroxyapatite in the presence of gamma-irradiated chitosan for the removal of malachite green

The fish processing sector produces millions of tons of trash annually-a biologically dangerous substance that could eventually turn into a source of pathogenic contamination. This work successfully shows how to extract tilapia fish scale hydroxyapatite with ultrasonic assistance and modify it using gamma-irradiated chitosan to remove malachite green from water samples. The prepared adsorbent was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, X-ray fluorescence, scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy, thermogravimetric analysis and dynamic light scattering. Isotherm modeling was employed to investigate the sorption process of malachite green. The results revealed that the adsorbent could be used to remove malachite green in aqueous media, with a maximum adsorption capacity of 285.7 mg g-1. A pseudo-second-order model was then fitted to the kinetic data. The R 2 value of 0.9851 obtained indicated that the adsorption behavior was consistent with the Langmuir model. Analysis of the computed thermodynamic parameters revealed that the adsorption of the dye was a spontaneous and exothermic process. Proper waste management practices not only ensure environmental responsibility but also contribute to positive community relations by minimizing the impact on the local environment.

Hydrogels Based on Chitosan and Nanoparticles and Their Suitability for Dyes Adsorption from Aqueous Media: Assessment of the Last-Decade Progresses

Water is one of the fundamental resources for the existence of humans and the environment. Throughout time, due to urbanization, expanding population, increased agricultural production, and intense industrialization, significant pollution with persistent contaminants has been noted, placing the water quality in danger. As a consequence, different procedures and various technologies have been tested and used in order to ensure that water sources are safe for use. The adsorption process is often considered for wastewater treatment due to its straightforward design, low investment cost, availability, avoidance of additional chemicals, lack of undesirable byproducts, and demonstrated significant efficacious potential for treating and eliminating organic contaminants. To accomplish its application, the need to develop innovative materials has become an essential goal. In this context, an overview of recent advances in hydrogels based on chitosan and nanocomposites and their application for the depollution of wastewater contaminated with dyes is reported herein. The present review focuses on (i) the challenges raised by the synthesis process and characterization of the different hydrogels; (ii) the discussion of the impact of the main parameters affecting the adsorption process; (iii) the understanding of the adsorption isotherms, kinetics, and thermodynamic behavior; and (iv) the examination of the possibility of recycling and reusing the hydrogels.

One-pot synthesis of iron oxide - Gamma irradiated chitosan modified SBA-15 mesoporous silica for effective methylene blue dye removal

The development of adsorption technology and the processing of radiation have both been influenced by chitosan adsorbent (γ-chitosan), a raw material with unique features. The goal of the current work was to improve the synthesis of Fe-SBA-15 utilizing chitosan that has undergone gamma radiation (Fe-γ-CS-SBA-15) in order to investigate the removal of methylene blue dye in a single hydrothermal procedure. High-resolution transmission electron microscopy (HRTEM), High angle annular dark field scanning transmission electron microscopy (HAADF-STEM), small- and wide-angle X-ray powder diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR) and Energydispersive X-ray spectroscopy (EDS) were used to characterize γ-CS-SBA-15 that had been exposed to Fe. By using N₂-physisorption (BET, BJH), the structure of Fe-γ-CS-SBA-15 was investigated. The study parameters also included the effect of solution pH, adsorbent dose and contact time on the methylene blue adsorption. The elimination efficiency of the methylene blue dye was compiled using a UV-VIS spectrophotometer. The results of the characterization show that the Fe-γ-CS-SBA-15 has a substantial pore volume of 504 m² g^-1 and a surface area of 0.88 cm³ g^-1. Furthermore, the maximum adsorption capacity (Q_max) of the methylene blue is 176.70 mg/g. The γ-CS can make SBA-15 operate better. It proves that the distribution of Fe and chitosan (the C and N components) in SBA-15 channels is uniform.

Surface Plasmon Resonance Sensor for Novel Detection of Histidine Based on the Hg2+ Induced Aggregation of AuNPs Followed by Preconcentration with Chitosan Gel as Solid-phase Biosorbent

This research work aims to propose an extraction method using chitosan as the sorbent and gold nanoparticles (AuNPs) as the colorimetric sensor for the development of a simple, cost-effective, rapid, sensitive, and selective detection method for histidine. The colorimetric assay is based on the aggregation of AuNPs in the presence of Hg2+ ions and histidine. The state of AuNPs generally changes from dispersion to aggregation. The change in state is accompanied by a corresponding change in color (from red wine to blue). Therefore, the solid phase extraction (SPE) method using chitosan as the sorbent was used to extract the AuNPs to improve the sensitivity of detection. It was found that the extraction by means of a sensor system using chitosan could increase the detection signal for histidine by 10 times. The calibration curve, which is the plot of absorbance ratio (A650/A528) against the concentration of histidine, shows a linear relation in the concentration range of 100 - 800 nM. The limit of detection (LOD) and limit of quantitation (LOQ) of the method were found to be 99.88 and 107.45 nM, respectively. Good recoveries were also obtained (range: 99.75 - 104.43%) with relative standard deviations (RSDs) below 5.89% in real water samples. Moreover, this method can be used for the selective detection of histidine even in the presence of other amino acids. The proposed method has been successfully used in the determination of histidine in mineral water samples.

Ultrasound-irradiated synthesis of 3-mercaptopropyl trimethoxysilane-modified hydroxyapatite derived from fish-scale residues followed by ultrasound-assisted organic dyes removal

We report a novel method for the synthesis of 3-mercaptopropyl trimethoxysilane-modified hydroxyapatite (FHAP-SH) derived from fish-scale residues by using ultrasound irradiation. Scanning electron microscopy, transmission electron microscopy, energy-dispersive spectroscopy, X-ray diffraction, and Fourier transform infrared spectroscopy were used for the FHAP-SH characterization. Then, the organic dye adsorption on the FHAP-SH was monitored through an ultrasound process. After the dye removal optimization, significant improvements were observed in the maximum adsorption capacities for Congo Red (CR, 500 mg g^-1), Coomassie Brilliant Blue G 250 (CB, 235 mg g^-1), and Malachite Green (MG, 625 mg g^-1). The adsorption behaviors of these dyes were fitted by using the Langmuir isotherm model with a high coefficient of determination values ranging from 0.9985 to 0.9969. The adsorption of the three dyes onto FHAP-SH was an endothermic process based on the adsorption thermodynamics model, while the adsorption kinetics analysis of the dyes presented a good alignment with the pseudo-second-order kinetics. The FHAP-SH exhibits a remarkably high adsorption capacity, is inexpensive, and fulfills the ecofriendly requirements of dye wastewater treatment, especially in the textile industry.