Phoenix dactylifera (date palm)-Derived Biochar Application for the Adsorptive Removal of Multiple Inorganics from Groundwater for Drinking Water Purposes

Groundwater contamination by inorganics creates serious health and environmental problems. Therefore, efficient, low-cost, and environmentally friendly techniques are needed to treat water to acceptable standards as it is used for drinking purposes in many countries. In this present study, biochar derived from Phoenix dactylifera (date palm) waste is investigated for the adsorption of multiple inorganic contaminants present in groundwater via packed bed column studies. The mechanism of adsorption was qualitatively determined using several characterization techniques. The effect of variations in flow rate, influent concentration, and bed height on the adsorption capacities of the biochar was investigated to derive the optimum parameters. The resultant optimum conditions which are pH 7, flow rate of 10 mL/min, and bed height of 1 cm were used to treat synthetic groundwater in field columns studies. The order of adsorption capacities (mg/g) of the ions was: copper (26.21 ± 0.05) > iron (3.58 ± 0.11) > potassium (3.23 ± 0.05) > zinc (3.01 ± 0.49) > manganese (0.78 ± 0.1) > nickel (0.09 ± 0.01) for cations and phosphate (17.2 ± 1.13) > sulfate (10.75 ± 0.4) > nitrate (2.00 ± 0.3) for anions. The biochar was also able to reduce/maintain the physiochemical parameters such as pH, color, turbidity, and total dissolved solids as well as the inorganics to below the World Health Organization drinking water guideline values. This indicates the suitability of the date palm biochar as adsorbent for drinking water treatment systems.