Removal of arsenic from groundwater using low cost ferruginous manganese ore

Removal of arsenic from water by electrocoagulation

“…The commonly used technologies include coagulation and precipitation with iron and aluminum salts (Edwards, 1994;Hering et al, 1996), adsorption onto activated alumina, activated carbon and activated bauxite (Gupta and Chen, 1978), ion exchange and reverse osmosis (Clifford, 1999). Some recent treatment technologies based on oxidation and adsorption are green sand filtration (Christen, 2000), iron oxide coated sand (Joshi and Chaudhuri, 1996), manganese dioxide coated sand (Bajpai and Chaudhuri, 1999), ferruginous manganese ore (Chakravarty et al, 2002), ferrihydrite (Jain et al, 1999), clay minerals (Manning and Goldberg, 1997) and zero-valent iron (Fendorf et al, 1997;Farrell et al, 2001;Su and Puls, 2001). Coagulation, precipitation and other adsorption techniques such as, activated alumina, and activated carbon, have been found to be not as efficient for As(III) removal as for As(V) removal.…”

Study on the Removal Performance of Natural Manganese Ore and Iron-Oxidizing Bacteria on the Arsenic

“…Though the solubility product of Ca(oH) 2 (K sp = 5.5 × 10 -6 ) is bigger than Mg(oH) 2 (K sp = 1.8 × 10 -11 ), the impact of Ca 2+ is larger. As can be seen from Figures 9-12, in the presence of HCO 3 − , SiO 3 2− , HPO 3 2− , the efficiency of arsenic removing was significantly reduced, while the presence of SO 4 2− has little effect on the the removal efficiency of eroded manganese ore on arsenic. The reason of four coexisting anions have negative impact is electrostatic repulsion between the coexisting anions and arsenic anion, anions aggregate in the surface of eroded manganese ore, occupy the adsorption site and has negative effect on the removal of arsenic.…”

“…5,1,2,4,8,12,20,25,30,35, 40 mg/L, after 48 hours' oscillation in the constant temperature oscillator, take out the supernatant after centrifugation and detect the concentration of the As. The adsorption isotherms of As (iii/V) were obtained, as shown in Figure 2 and Figure 3.…”

“…In this paper, the influence of Ca 2+ , Mg 2+ , HCO 3 − , SO 4 2− , SiO 3 2− , HPO 3 2− on the adsorption effects of manganese ore were investigated by using the control variable method, the experimental results are shown in Figures 7-12.…”

“…because of the low cost and good effect, the technology that through the adsorption method to direct removes arsenic from the water has been a major concern among these studies [3]. S. Chakravarty [4] and others found that the natural manganese can be directly applied to the arsenic in water without pre-treatment; Wen Zhipan [5] and others' researches showed that due to the large surface area of iron and manganese oxides, it has a good removal effect on the arsenic; through the relevant study, Tomohito Kameda [6] and others found that arsenic in the water can form a total precipitation with the manganese oxide, which can be removed easily. These studies confirmed that the removal of arsenic by manganese ore has research value.…”