Removal of Arsenic contaminated water by continuous column adoption using laterite grains as a low-cost adsorbent.

Abstract

Arsenic contamination in water bodies presents a significant health risk, particularly in rural areas in developing countries. To treat arsenic-contaminated water economically in developing countries, it is crucial to propose low-cost water treatment techniques. In this study, the arsenic treatment performance was investigated using continuous column adsorption experiments packed with laterite grains taken from Tha. ch Thát district, Hanoi, Vietnam. Initially, the physical and physicochemical properties of tested samples were measured. The continuous column adsorption experiments were carried out to assess the effects of initial arsenic solution concentration and calcination of tested grains (at 550◦C) on the adsorption performance by using raw and calcined laterite. The results show that Scanning Electron Microscopy analysis with Energy-Dispersive X-ray Spectroscopy confirmed the existence of iron oxides/hydroxides on the tested samples, which may induce the arsenic adsorption affinity to laterite grains. Continuous column adsorption showed improved breakthrough time with lower initial arsenic concentrations. The Bed Depth Service Time model suggested a minimum of 0.77 cm column height for safe drinking water with 503.55 mg arsenic/L laterite adsorption capacity. Although the calcination didn’t enhance surface area (raw laterite: 61.0 m2/g, calcined laterite: 60.2 m2/g), it improved arsenic treatment in continuous column adsorption with enhancement of breakthrough time from 265min to 310 min. In summary, tested laterite grains possess a high ability to treat arsenic contaminated water.