Performance assessment of Zn–Sn bimetal oxides for the removal of inorganic arsenic in groundwater

• DOI: 10.1016/j.gsd.2021.100600
• Publication Date: 2021-04-30T00:04:08Z
• Authors: Martine Thomson P...; Pavan Kumar Gautam; Sintu Samanta; Suman; Pargin Bangotra; Sushmita Banerjee
• Keywords: Bimetal; Langmuir adsorption model

Abstract Millions of people worldwide are compelled to consume water with high arsenic levels that affect their health adversely. This point intrigued the researchers to develop an effective and economical solution to reduce the high arsenic level to the safe standard limits. This research focuses on the adsorptive removal of arsenate ions onto a novel bimetal oxide particle prepared by mixing Zn and Sn at different atomic ratios. The fabricated bimetallic oxides were characterised by applying various techniques such as XRD, SEM-EDX, BET and FTIR to comprehend the morphology and physico-chemical properties. Batch adsorption experiments were conducted to monitor the arsenate removal under varying process variables such as pH, dosage, contact time etc. The investigation revealed that Zn/Sn bimetal oxide particles prepared with atomic ratio 2:1 showed maximum arsenate removal efficiency compared to other atomic ratios. The removal was found to be pH, dose and temperature dependent and the highest removal of 98.8% was observed at pH 4 with 0.125 g/L of adsorbent dose with an initial dye concentration of 2.5 ppm at 45 °C. Kinetic study and isotherm study of the sorption experiment showed that the pseudo-second order model and Langmuir isotherm model were best suited for the adsorption of arsenate ion the prepared Zn/Sn bimetal oxide adsorbent. The maximum adsorption capacity of the adsorbent computed as 41.29 mg/g at 318K. A regeneration study revealed that 0.1 M phosphoric acid showed 96% desorption of adsorbate. The practical applicability of the Zn/Sn bimetal oxide was also explored to evaluate the performance in real condition.