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An activated biochar was produced from post-coagulation sludge (also called water treatment residuals or water treatment sludge) in the pyrolysis process at 800 °C in a nitrogen atmosphere and chemical activation using NaOH. The produced adsorption material was characterised by an S surface area of 439 m/g, a total volume of pores of 0.301 cm/g, and an average pore size of 1.4 nm. FTIR analysis reveals the presence of primarily C-H, C-O, N-H, C-N, and O-H groups on the activated biochar surface. The batch adsorption process was conducted for three dyes: Acid Red 18, Acid Green 16, and Reactive Blue 81. In the study, the effect of pH, contact time, adsorption kinetics, and adsorption isotherm was determined. The studies showed that, for all dyes, the highest efficiency of the process was achieved at a pH of 2. The results indicate the occurrence of a chemical adsorption process, as evidenced by the best fit to the experimental results obtained with the pseudo-second-order kinetics model and the Elovich model. In the case of the adsorption isotherm, the SIPS model best describes the adsorption for Acid Red 18 and Reactive Blue 81, and the Jovanovic model describes the adsorption of Acid Green 16.
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http://dx.doi.org/10.3390/ijms26167912 | DOI Listing |
Environ Sci Pollut Res Int
September 2025
Department of Chemistry Education, Farhangian University, P.O. Box 14665-889, Tehran, Iran.
This study introduces a back filter installed at the end of the exhaust pipe of city buses. The impact of the metal type used in its construction on the absorption of suspended particles and the reduction of sulfides in diesel engine exhaust gases is investigated. The back filter is constructed from three metals: copper, zinc, and nickel.
View Article and Find Full Text PDFEnviron Monit Assess
September 2025
Department of Civil Engineering, Faculty of Engineering, Karpagam Academy of Higher Education, Pollachi Main Road, Eachanari Post, Coimbatore, Tamil Nadu, 641021, India.
Synthetic dyes, such as Congo red (CR), pose serious threats to human health and aquatic ecosystems because of their carcinogenicity and resistance to degradation, necessitating the development of efficient and eco-friendly remediation strategies. In this study, silver nanoparticles (AgNPs) were synthesized via a green method using Ocimum sanctum (holy basil) leaf extract and applied for CR dye removal from aqueous solutions. The adsorption process was optimized using response surface methodology (RSM) based on Box-Behnken design (BBD), evaluating the influence of key parameters including pH, AgNP dosage, initial dye concentration, contact time, and temperature.
View Article and Find Full Text PDFAnn N Y Acad Sci
September 2025
School of Nuclear Science and Technology, University of South China, Hengyang, China.
Lutetium (Lu(III)), a heavy rare earth element, plays a critical role in advanced industrial processes and nuclear medicine applications. Given its high economic value and potential environmental risks, the recovery of Lu(III) from medical wastewater is both necessary and urgent. However, previous studies on the adsorption behavior of Lu(III) have been limited by low adsorption capacity, competition from coexisting metal ions, and the influence of environmental temperature.
View Article and Find Full Text PDFInt J Biol Macromol
September 2025
Key Laboratory of Oil & Gas Fine Chemicals, School of Chemical Engineering, Xinjiang University, Urumqi, 830046, China.
With the acceleration of global industrialization, a large amount of polluted wastewater is discharged indiscriminately, which both pollutes the environment and threatens human health. In this study, by constructing a binary system of unsaturated polyester resin/carboxychitosan, and improving the inherent defects of carboxychitosan aerogel, we successfully prepared aerogels with high porosity, low density, and laminar porous structure for water remediation by using a combination of the sol-gel method and directional freezing technology. Thanks to the synergistic effect of surface wettability and special pore structure, the aerogel not only adsorbs and separates MB and Pb(II) efficiently with a separation efficiency of more than 99 %, but also has a separation efficiency of 99.
View Article and Find Full Text PDFBioresour Technol
September 2025
School of Chemical Engineering, Xiangtan University, Xiangtan 411105, China. Electronic address:
Biomass containing inorganic ingredients can be converted into highly porous biochar via in-situ activation and templating process. Here, N-doped biochar is obtained by pyrolysis of spinach organs for efficient dye removal, using methylene blue (MB) as a model dye, and pyrolysis temperature plays a critical role in determining both porosity and N-species within biochar. Significantly, leaf biochar (LC-900) as pyrolyzed at 900 °C shows surface areas of 1263 m/g larger than that of biochar from stem and root, indicating a dependence on the biomass organ source.
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