(392d) Removal of Arsenic and NORM from Water with Novel Clay Adsorbents Developed Using Camd

Arsenic, a carcinogenic metal is a widely spread contaminant in groundwater. Similarly, naturally occurring radioactive materials (NORM) including barium, strontium and radium are hazardous metals present in produced water. In this study clay-based adsorbents are used to remove the heavy metal arsenic and NORMS from water and produced water, respectively. Current separating agents of heavy metals and NORM have a limited adsorption capacity [1,2]. In our previous work, we have developed a computer-aided molecular design (CAMD) framework to design novel adsorbent candidates with enhanced adsorption capacities based on the group interaction parameters for arsenic and NORM remediation using clay materials [3]. The metaheuristic efficient ant colony optimization (EACO) algorithm is used to maximize the adsorption capacity with structural possibilities, thermodynamic property, and process conditions as constraints. The objective of this work is to synthesized designed adsorbents by co-precipitation method. The morphology and structure of the fabricated molecules were characterized using X-ray diffraction and X-ray fluorescence spectroscopy. With the help of a batch reactor at a controlled temperature, equilibrium adsorption for arsenic and NORM was performed as function of arsenic concentration in the solution, contact time and adsorbent dosage. Langmuir and Freundlich isotherms models are predicted for both arsenic and NORM. The cations present in the water is analyzed with the help of inductive coupled plasma optical emission spectroscopy. The adsorption capacity for arsenic from water and NORM from produced water is found to be an order of magnitude higher than that can be obtained by conventional clay adsorbents.

Keywords: Adsorbents, NORM, CAMD, EACO algorithm.

References:

• Benavides, P. and Diwekar, U., 2015. Optimal design of adsorbents for NORM removal from produced water in natural gas fracking. Part 1: Group contribution method for adsorption. Chemical Engineering Science, 137, pp.964-976.
• Benavides, P. and Diwekar, U., 2015. Optimal design of adsorbents for NORM removal from produced water in natural gas fracking. Part 1: Group contribution method for adsorption. Chemical Engineering Science, 137, pp.964-976.
• Doshi, R., Mukherjee, R. and Diwekar, U., 2018. Application of Adsorbate Solid Solution Theory To Design Novel Adsorbents for Arsenic Removal Using CAMD. ACS Sustainable Chemistry & Engineering, 6(2), pp.2603-2611.