Remediation of arsenic-contaminated soils via waste-reclaimed treatment agents: Batch and field studies

Abstract

The potential of three different waste-reclaimed treatment agents (WRTAs) for removing arsenic was evaluated via laboratory-scale batches, column experiments, and field tests. WRTA1 was synthesized using acid mine drainage sludge (AMDS), cement, and sand. WRTA2 and WRTA3 were synthesized by adding fly ash or Ca(OH)(2), respectively, to WRTA1. The maximum adsorption capacities of WRTA1, WRTA2, and WRTA3 for As(III) using the Langmuir model were 16.6 mg g(-1), 14.5 mg g(-1), and 20.6 mg g(-1), respectively, and for As(V) were 29.6 mg g(-1), 27.3 mg g(-1), and 31.3 mg g(-1), respectively. The pseudo-second-order equation for the adsorption of As(III) and As(V) fit the kinetics data well. The column study showed that the WRTAs are very effective adsorbents and exhibit > 80% removal of As from the contaminated soil. The inhibition of As accumulation in plants (i.e., rice, chili, and sesame) by the WRTAs was evaluated and showed a 96% inhibition in As accumulation in chili roots for WRTA2. The suggested WRTAs are promising agents for the removal of As and heavy metals from heavily contaminated agricultural soil.