The quest for sustainable development and green chemistry had led to the design and synthesis of advanced adsorbent materials for efficient removal of pollutants in industrial effluents. Magnetic halloysite nanotubes with chitosan nanocomposite sponges were prepared by combining solution-mixing and freeze-drying. Magnetic@chitosan/halloysite (FeO-HNT/CS) and spongelike chitosan/halloysite (HNT/CS) were used as adsorbents for the removal of Congo red dye in aqueous solution in a batch process. The as-prepared composites were characterized using scanning electron microscopy, energy-dispersive X-ray analysis, X-ray diffraction, vibrating-sample magnetometry, thermal gravimetry-differential scanning calorimetry, and Fourier transform infrared spectroscopy. Data from kinetic study were analyzed with pseudo-first-order and pseudo-second-order models, whereas the mechanism was analyzed using Bangham's, Elovich's, intraparticle, and double-exponential diffusion models. The equilibrium data were evaluated using Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich isotherm models. The adsorption kinetics of dye removal followed the pseudo-first-order model with average rate constants of 0.260 and 0.196 min for FeO-HNT/CS and HNT/CS, respectively. The Langmuir adsorption isotherm best fitted the equilibrium data with > 0.9 with maximum adsorption capacities of 41.54 and 54.49 mg g obtained for HNT/CS and FeO-HNT/CS, respectively. Negative values of Δ° obtained from thermodynamic studies revealed that the adsorption process was spontaneous. The values of Δ° and Δ° obtained for Congo red dye removal were 69.46 and 39.54 kJ mol and 240.5 and 145.1 J mol K for HNT/CS and FeO-HNT/CS, respectively. The results indicated that CS-HNT is an excellent adsorbent; however, its magnetic modification further improved its recyclability and enhanced the performance for the removal of Congo red dye from aqueous solution.
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http://dx.doi.org/10.1021/acsomega.8b02960 | DOI Listing |
Chemosphere
January 2025
Department of Industrial Engineering, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano, Salerno, Italy.
This research aims to design a novel selective and multifunctional adsorbent based on Al/Cu modified hemp fibres as a novel and multifunctional adsorbent for removing different classes of pollutants. The adsorbent, which was widely characterized, was shown to be more effective in removing anionic dyes compared to cationic ones. Among the tested dye, methyl orange was selected to understand how different parameters, such as temperature (20-80°C), contact time, pH (2-12), initial dye concentration (50-300 ppm), salinity and adsorbent dosage (1-10 g/L) affect the removal capacity.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, China; Open Studio for Marine Corrosion and Protection, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266100, China; Key Laboratory of Ocean Observation and Information of Hainan Province, Sanya Oceanographic Institution, Ocean University of China, Sanya 572024, China. Electronic address:
Improving the adsorption capacity of materials for pollutants by means of modification is an important direction in the research of water treatment technology. To improve the applicability of sodium alginate composites in the field of adsorption, magnetic sodium alginate-based hydrogel microsphere adsorbent material FeO@SA/PEI-Fe (FSPF) was synthesized in a single step by using polyethyleneimine grafting modification of sodium alginate by sol-gel method. The material was used for the removal of direct blue GL (DB 200) and direct date red B (DR 13) from simulated wastewater, as well as Cu(II) and Pb(II) from simulated wastewater with heavy metal ions.
View Article and Find Full Text PDFFront Fungal Biol
December 2024
Water Systems and Biotechnology Institute, Faculty of Natural Sciences and Technology, Riga Technical University, Riga, Latvia.
The growing demand for novel enzyme producers to meet industrial and environmental needs has driven interest in lignocellulose-degrading fungi. In this study, lignocellulolytic enzyme production capabilities of environmental fungal isolates collected from boreal coniferous and nemoral summer green deciduous forests were investigated, using Congo Red, ABTS, and Azure B as indicators of cellulolytic and ligninolytic enzyme productions. Through qualitative and quantitative assays, the study aimed to identify promising species for lignocellulose-degrading enzyme secretion and assess their potential for biotechnological applications.
View Article and Find Full Text PDFDalton Trans
January 2025
Departamento de Química Inorgánica, Facultad de Química y Farmacia, Centro de Energía UC, Centro de Investigación en Nanotecnología y Materiales Avanzados CIEN-UC, Pontificia Universidad Católica de Chile, Avenida Vicuña Mackenna, 4860, Santiago, Chile.
Recalcitrant pollutants are challenging to degrade during water treatment processes. Methylene blue (MB), a cationic dye, is particularly resistant to degradation and is environmentally persistent. Heterogeneous photocatalysis has emerged as a suitable strategy for removing such pollutants from water.
View Article and Find Full Text PDFSci Rep
January 2025
School of Metallurgy and Materials Engineering, Iran University of Science and Technology, Narmak, Tehran, Iran.
In this study, in situ-synthesized ZnO/g-CN based composites were used as photocatalysts for organic pollution removal. These nanocomposites were prepared through simple calcination of a mixture of melamine and ZnO nanoparticles and underwent comprehensive evaluation of their structural, morphological, optical, and photocatalytic properties, using various analytical techniques. As the g-CN content increased, the band gap decreased from 3.
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