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Dyes are responsible for major environmental issues globally due to their toxicity, large-scale production, and extensive use in various industrial sectors. Pollution caused by hazardous dyes is mainly due to textile waste, which is constantly discharged into the aquatic system, often causing harm to humans and affecting water quality. In recent years, the removal of dyes from industrial textile wastewater has been a major challenge. Numerous technologies and methods have been developed to remove dyes from wastewater and meet clean water requirements. In this study, the effectiveness of activated carbon prepared by chemical activation of jujube stones for textile wastewater treatment was investigated. The effects of the concentration of H3PO4 and the carbonization temperature on the activated carbon's properties were studied. Several physicochemical methods, including Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction, methylene blue index, Boehm titration, iodine index and pH point of zero charge, were considered to characterize the produced adsorbents. To assess the quality of the two studied textile effluents (Mustard and Violet), the following parameters were used: biological oxygen demand (BOD), chemical oxygen demand (COD), turbidity, suspended particles and dissolved solids, before and after treatment with the produced activated carbon. Untreated wastewater analysis revealed high values for almost all parameters: pH > 9, COD of 302.72 mg/L and 230.68 mg/L for Mustard and Violet effluent, respectively. Both effluents from an industrial textile factory exhibited a COD/BOD ratio higher than three, which restricts their biodegradability. Examination of the effect of contact time and activated carbon dosage on the treatment of the two effluents showed that 4 g/L of activated carbon and 60 min of contact time were sufficient for optimal treatment, resulting in pollutant removal rates of 81.03 and 84.65% for the Violet and Mustard effluents, respectively. The results of this research highlight the efficiency of activated carbon derived from jujube stones as a cost-effective adsorbent for the treatment of real textile wastewater. [ABSTRACT FROM AUTHOR]

We make use of chemical activation with phosphoric acid to prepare an activated carbon from date stones (DSAC). After characterization for surface area and pore volume, it was tested as an adsorbent for gallic acid (GA) removal from aqueous solutions: Operating variables including contact time (410 min), adsorbent dosage (0.1 g in 150 mL), GA concentration (10 mg/L) and solution pH (4.5) were optimized using the Box-Behnken design (BBD) under response surface methodology (RSM) approach. Adsorption of GA onto DSAC may be described by the pseudo-second-order kinetics model equation suggesting that the process is chemisorption. The equilibrium data fitted the Langmuir isotherm model with a maximum capacity of 156 mg/g (25°C, pH 4.5). The GA adsorption process was found to be exothermic, while ΔG° was negative implying that the reaction is spontaneous. [ABSTRACT FROM AUTHOR]

The low-cost activated carbon prepared from Date stone, an agricultural solid waste by-product, were prepared by chemical activation with sulphuric acid for the removal of lead and zinc from aqueous solutions has been studied as a function of pH, contact time, metal concentrations and adsorbent concentrations. Adsorption equilibrium was reached after an equilibration time of 60 min and adsorption kinetics data were tested using Lagergren pseudo-first-order and pseudo-second order, the studies showed the adsorption process followed pseudo-second-order rate model. The maximum removal of Pb2+ and Zn2+ is observed at pH 6.0 (94.4%) and 7.0 (93.2%) respectively at initial concentration 20 mg/L. The isotherm equilibrium data were well fitted by the Langmuir and Freundlich models. The adsorption capacity (qmax) calculated from the Langmuir isotherm was 19.64 mg Pb2+/g and 10.41 mg Zn2+/g at an initial pH of 6.0 at 20 ± 2°C. [ABSTRACT FROM AUTHOR]