Synergetic studies on the influence of the integrated cellulose on the adsorption of selenite and selenite by cellulose/phillipsite composite: Steric and energetic assessments

Natural zeolite of the phillipsite phase was integrated into biocomposite with cellulose fibers (CF/Ph) and characterized as an effective and environmental adsorbent for both selenite (Se (IV)) and selenate (Se (VI)). The retention studies were performed based on the experimental factors in addition to both classic and advanced equilibrium modeling. The composite showed enhanced retention properties for both Se (IV) (196.4 mg/g) and Se (VI) (144.7 mg/g) as compared to raw phillipsite (Se (IV) (142.13 mg/g) and Se (VI) (113 mg/g)) and cellulose (Se (IV) (42.5 mg/g) and Se (VI) (6.4 mg/g)). Based on the synergetic parameters, the integration process enhanced the quantities of the existing active sites at a considerable rate (Nm = 57.3 mg/g (Se (IV)) and 48 mg/g (Se (VI))) as compared to phillipsite and cellulose. The number of the two adsorbed selenium ions is about 4, demonstrating multi-ionic uptake of them in vertical orientations. The energetic investigation (9–11 kJ/mol) validates the retention of two forms of selenium by mainly physical mechanistic processes (dipole bonding and/or van der Waals forces and/or hydrogen bonding). Regarding the thermodynamic functions, the reported behaviors demonstrate the exothermic and spontaneous uptake of both selenite (Se (IV)) and selenate (Se (VI)) by CF/Ph. Also, the composite possesses remarkable recyclability and higher efficiency as compared to several studied structures and can be applied in realistic remediation process even in existence of other chemical contaminants.