South African sands as an alternative to zero valent iron for arsenic removal from an industrial effluent: Batch experiments

• An iron-based adsorbent was used to remove arsenic from an industrial effluent.
• Kinetics studies revealed that arsenic adsorption fits pseudo-second order rate.
• Oxygen’s presence increases the arsenic removal of the reactant substrates.
• The presence of sulfates and nitrates increases the arsenic removal efficiency

This work aimed to verify the potentials of two sands as a valid alternative of zero valent iron (ZVI) for the removal of arsenic from an industrial effluent. Batch experiments were conducted using Umgeni sand (US), Berea Red Sand (BRS), two types of zero valent iron (GmbH ZVI, and Connelly-GPM ZVI) and a mixture of BRS and GmbH ZVI. The experiments were carried out to study the removal kinetics of arsenic under semi-aerobic and anaerobic conditions and in the presence of sulfate, nitrate and phosphate anions. The GMP ZVI showed the best performance in terms of arsenic removal (100% of removal after 7 h). BRS showed 61.75% of arsenic removal by itself and 86.32% of removal in combination with GmbH ZVI. The presence of oxygen increased the Arsenic removal efficiency for all substrates investigated. Sulfate and nitrate anions increased the removal efficiency while phosphate affected the arsenic removal efficiency.