• Dr. Subhashis Biswas

Contamination of Arsenic species in groundwater and surface water is a serious health related issue across many parts of India, especially in Gangetic West Bengal. Arsenic (III) concentration is over 50 micrograms/liter is harmful for human body, and it is a major challenge to remove poisonous arsenic compounds from usable water in large scale across India. Removal of Arsenic (III) species from ground water can be performed by “proximity effect” mechanism. This works via presence of aqueous As (III) species in the “proximity” of semiconducting mineral surface in oxidizing environment via electron transfer-spin transfer mechanism. HF-DFT methods and B3LYP hybrid methods are employed in Gaussian 03 to calculate adsorption energies of As(OH)3 on PbS-galena (100) surface, and results show that the co-adsorption of O2 and As(III)-species on galena(100) surface occurs via electron exchange spin transfer mechanism. Singlet state of molecular oxygen is more favorable spin state when it remains co-adsorbed on galena along with As(III) species. This study will give insight into possible removal techniques of water soluble As(III) species from usable water.

Hartree-Fock theory, B3LYP, co-adsorption, spin-flip, As(OH)3, removal, oxidizing

"Interaction of As(OH)3 -species with semiconducting mineral surface via proximity effect : A computational modeling study for Arsenic removal from ground water", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.12, Issue 9, page no.d148-d151, September-2025, Available :http://www.jetir.org/papers/JETIR2509321.pdf

"Interaction of As(OH)3 -species with semiconducting mineral surface via proximity effect : A computational modeling study for Arsenic removal from ground water", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.12, Issue 9, page no. ppd148-d151, September-2025, Available at : http://www.jetir.org/papers/JETIR2509321.pdf