Study of iron-based metal–organic framework for selenite removal from water

Selenite (SeO32−, Se (IV)) as well as selenate (SeO42−, Se (VI)) are the main forms of selenium existing in the aqueous media and acknowledged to upshot critical mutilation to well-being on surplus intake. Water is considered as one of the supreme itineraries for selenium inlet because of its adulteration with selenium via geogenic and anthropogenic practices. On the whole, Se (IV) is more noxious as compared to Se (VI); therefore, it is essential to develop remedial solution for their removal. The current work employs adsorption method and validates metal–organic framework based on iron, MIL-53 (MIL is fully known as Material of Institute Lavoisier), for selenium (IV) eradication from water. The Fe-MOFs are studied about influence of pH, preliminary selenite levels, time of contact, adsorbent dosage, etc., on the selenium removal efficacy. The selenium quantification is done with ion chromatography coupled with a conductivity detector. The study reveals that metal–organic framework based on iron could significantly remove selenite in aqueous conditions at an optimized pH 7 and a removal time of 4 h. Based on the higher correlation coefficient (R2) criterion, the selenite adsorption onto MIL-53 (Fe) is proposed to follow pseudo-second-order kinetics (R2 = 0.9655) and Langmuir adsorption (R2 = 0.9948) mechanism. Multiple regeneration and reuse experiments show that the MIL-53 (Fe) remained reusable with only 4% reduction in the adsorption efficiency after three cycles. The present finding thus presents a new media for selenite remediation from water.