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Fe(II) removal from acidic aqueous solutions using Conocarpus sp. biochar or chemically modified biochar prepared by synthesizing Mg(OH)2 on biochar surface as well as their comparison with zeolite sorbent (natural clinoptilolite) was investigated. Batch experiments were conducted as a function of initial pH of 2-5, contact time of 5-180 minutes and initial concentration of 10-200 mg l -1 (0.18-3.58 mmol l -1). The sorption data indicated that the pseudosecond-order kinetic model was the best model to simulate adsorption of Fe(II) onto the all sorbents and could generally be described by the Freundlich model. The higher sorption capacities for Fe(II) ions were generally pronounced for chemically modified biochar (84.6-99.8%) followed by biochar (38.3-97.6%) than those that were achieved by zeolite (12.3-95.5%). Thus, remediating acidic wastewater contaminated with Fe(II) might be possible using Conocarpus biochar, especially the chemically modified biochar.

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This study focuses on the chemical analysis of the available brands of domestic bottled water in Riyadh City, Saudi Arabia. The distribution of the chemical constituents (major, minor, and trace elements) is determined and compared with the chemical content labeled on the bottles and with drinking water standards of Saudi Arabian, World Health Organization, and U.S. Environmental Protection Agency. The obtained results indicated that except for fluoride and bromate, the concentrations of dissolved salts, soluble cations and anions, nitrate, and trace elements of most bottled waters on sale were within the permissible limits set by standards used. On the other hand, the comparison between determined and reported label values recorded a substantial variation in some parameter values. Results indicated that more than 18 % of the sampled bottled waters exceeded the allowable limits for drinking water. Generated Piper diagrams revealed that the majority of investigated waters were sodium chloride-sulfate type; however, the hydrochemical modeling indicated that all water samples were undersaturated for anhydrite, gypsum, and halite.