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Activated Watermelon seeds (AC-WmS) were successfully used as adsorbent for the competition removal of two antibiotics Sulphamethazine (SMT) and Sulfamethoxazole (SMX) from aqueous media in single and binary systems. The effects of various parameters influencing the adsorptive competition of SMT and SMT, such as contact time, adorbent dose and pH on the adsorption extent were investigated and examined in a batch mode. The pH zero-pointcharge of AC-WmS-500 is pHZPC = 5.8. The adsorption capacities are 97.8 mg/g and 109.25 mg/g for SMT and SMX, respectively. Equilibrium data were well represented by the Freundlich model for SMT and SMX in binary system. The qmax of SMX in the single system was decreased from 97.8 to 35.16 mg/g. Theoretical study was made for the determination of the charge density on the sites of the reagents, the prediction of the electrophilic/nucleophilic character of the reagents, the prediction of the local reactivity of the reagents, the indices of local electrophily and of nucleophily, by the method of the density functional theory DFT/B3LYP, with the base 6–311 G (d, p) shows that the competitive adsorption between the two antibiotics were observed and it was noticed that SMT was favoured as well as being more electrophilic than SMX, and greater interaction with surface sites in the single and binary system with an removal efficiency forSMT and SMX of 94% and 85%, respectively. The theoretical results are in good accordance with the experimental data reported. [ABSTRACT FROM AUTHOR]

The main objective of this study was to investigate the potential of Natural Safiot Clay (NSC) obtained from Safi city (Morocco), as an adsorbent for the removal of two cationic dyes such as Basic Blue 9 (BB9) and Basic Yellow 28 (BY28) from single and binary systems in aqueous solutions. Natural safiot clay was characterised using different physical-chemical methods, including X-ray fluorescence, Energy Dispersive X-ray spectroscopy (EDX), Fourier Transform Infrared (FT-IR) and pH of the point of zero charge (pHZPC). X-ray fluorescence results indicate high percentages of SiO2 (47.44%) and Al2O3 (31.24%). FT-IR spectrum identified kaolinite as the major mineral phase in the presence of quartz, calcite, and dolomite. The effects of various experimental parameters, such as initial dye concentration, adsorbent dose, initial pH and contact time on the adsorption extent were investigated and examined in a batch mode. For both dyes and in single and binary systems, the dye removal efficiency increases with increasing adsorbent dose, decreases with increasing initial dye concentration and varied with dye solution pH. Moreover, the experimental results indicate that the Langmuir model and the pseudo-second-order provide the best correlation of the experimental data in the two systems studied. The electrophilicity power of dyes affects the removal efficiency. The theoretical study proves that BB9 (ω = 6.178) is more electrophilic than BY28 (ω = 2.480), and more interactions with surface sites in the single and binary system with a removal efficiency of 96.20% to 95.57% and 85.32% to 61.48% for BB9 and BY28, respectively. The theoretical results are in good accordance with the experimental data reported. [ABSTRACT FROM AUTHOR]