Effects of adsorbent dose, its particle size and initial arsenic concentration on the removal of arsenic, iron and manganese from simulated ground water by Fe 3+ impregnated activated carbon

Abstract

This paper presents the observations of the study on arsenic removal from a contaminated ground water (simulated) by adsorption onto Fe 3+ impregnated granular activated carbon (GAC-Fe). Fe 2+, Fe 3+ and Mn 2+ have also been considered along with arsenic species in the water sample. Similar study has also been done with untreated granular activated carbon (GAC) for comparison. The effects of adsorbent dose, particle size of adsorbent and initial arsenic concentration on the removal of As(T), As(III), As(V), Fe 2+, Fe 3+ and Mn 2+ have been discussed. Under the experimental conditions, the optimum adsorbent doses for GAC-Fe and GAC have been found to be 8 g/l and 24 g/l, respectively with an agitation time of 15 h. Particle size of the adsorbents (both GAC and GAC-Fe) has shown negligible effect on the removal of arsenic and Fe species. However, for Mn removal the effect of adsorbent particle size is comparatively more. Percentage removal of As(T), As(V) and As(III) increase with the decrease in initial arsenic concentration (As 0). However, the increase in percentage removal of all the arsenic species with decrease in As 0 are less for higher value of As 0 (3000–500 ppb) than those of the lower value of As 0 (500–10 ppb). The % removal of As(T), As(III), As(V), Fe, and Mn were ∼95%, 92.4%, 97.6%, 99% and 41.2%, respectively when 8 g/l GAC-Fe was used at the As 0 value of 200 ppb. However, for GAC these values were ∼55.5%, 44%, 71%, 98% and 97%. The pH and temperature of the study were 7 ± 0.1 and 30 ± 1 °C, respectively.