Arsenic removal from aqueous water using pectin stabilised nano zero valent iron particles/neem bark supported (P-NZVI/NBP) treatment system

Abstract

ABSTRACT Exposure to arsenic (As) contaminated groundwater may be lethal to human health, paving the way to develop remediation strategies. This study aims at assessing the efficiency of pectin stabilised nano zero valent iron particles (P-NZVI) in arsenic removal through batch and column experiments. Results from batch experiment reveals that, As (III) removal efficiency of P-NZVI particles is directly proportional to contact time, quantity of P-NZVI with decreasing pH of the aqueous solution. Complete removal (2 ppm) of As (III) was achieved in 10 minutes with the mass concentration of P-NZVI at 0.5 g L−1 at pH 4.0 under batch experiment. The adsorption kinetics data were well fitted with pseudo second order model and the adsorption data obeyed the Langmuir and Freundlich equation with maximum adsorption capacity of 28.44 mg g−1 under batch study. Furthermore, column study with P-NZVI under Neem Bark Powder (NBP) supported treatment column with different bed height (10 cm, 20 cm) indicates that P-NZVI is superior in As(III) and As(V) removal under NBP supported treatment column. The breakthrough time, exhaustion time and bed capacity q o of the column increased with increasing bed height for both As(III) and As(V). The column experimental data fits well in Thomas and Yoon-Nelson theoretical model with coefficients of determination ranging from 0.92 to 0.94. Thus, the synthesised P-NZVI particles were eco-friendly and can easily be separated after their application in removing arsenic.