title: Ultimate selenium(IV) monitoring and removal from water using a new class of organic ligand based composite adsorbent.
abstract: This work reports the selenium (Se(IV)) detection and removal from water by ligand functionalized organic-inorganic based novel composite adsorbent. The composite adsorbent was prepared by direct immobilization of N,N'-di(3-carboxysalicylidene)-3,4-diamino-5-hydroxypyrazole onto the mesoporous silica monolith. The adsorbent exhibited distinct color change in the presence of various concentrations of Se(IV). This was characterized by UV-vis spectroscopy, and the color change was observed by naked-eye observation. The detection limit was determined to be 1.14 μg/L. The effect of solution pH, interferential metal ions, contact time, initial Se(IV) concentration, and adsorbent regeneration were evaluated. The maximum sorption capacity was determined based on the initial concentration. The data fitted well to the Langmuir isotherm model, and the maximum Se(IV) sorption capacity was 111.12 mg/g. The presence of diverse competing ions did not affect the Se(IV) sorption capacity, and the adsorbent had almost no sorption capacity for these coexisting ions, which suggests the high selectivity to Se(IV) ions. The adsorbed Se(IV) was eluted with suitable eluent (0.10 M NaOH) and simultaneously regenerated into the initial form for the next operation. The excellent reusability of the adsorbent was justified after eight consecutive sorption-elution-regeneration cycles. The proposed adsorbent is cost-effective and environmentally friendly and a potential candidate for treatment of water containing Se(IV).
authors.affiliation: Actinide Coordination Chemistry Group, Quantum Beam Science Center, Japan Atomic Energy Agency (SPring-8), Hyogo 679-5148, Japan. Electronic address: rawual76@yahoo.com.
authors.forename: Md Rabiul
authors.initials: MR
authors.lastname: Awual
authors.affiliation: Actinide Coordination Chemistry Group, Quantum Beam Science Center, Japan Atomic Energy Agency (SPring-8), Hyogo 679-5148, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Yaita
authors.affiliation: Actinide Coordination Chemistry Group, Quantum Beam Science Center, Japan Atomic Energy Agency (SPring-8), Hyogo 679-5148, Japan.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Suzuki
authors.affiliation: Actinide Coordination Chemistry Group, Quantum Beam Science Center, Japan Atomic Energy Agency (SPring-8), Hyogo 679-5148, Japan.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Shiwaku
mesh_terms: D000327:Adsorption; D004784:Environmental Monitoring / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D008024:Ligands; D009930:Organic Chemicals; D018036:Selenium Compounds / Q000032:analysis* / Q000302:isolation & purification; D012822:Silicon Dioxide; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D018508:Water Purification
chemical_list: D008024:Ligands; D009930:Organic Chemicals; D018036:Selenium Compounds; D014874:Water Pollutants, Chemical; D012822:Silicon Dioxide
keywords: Competing ions; Composite adsorbent; Monitoring and removal; Reusability; Selenium(IV)