Evaluation of adsorption performance and quantum chemical modeling of pesticides removal using cell-MG hybrid adsorbent

Abstract

Magnetite (MG) modified cellulose membrane (Cell-MG), obtained by reaction of 3-aminosilane and subsequently with diethylenetriaminepentaacetic acid dianhydride functionalized waste Cell fibers (Cell-NH2 and Cell-DTPA, respectively), and amino-modified diatomite was used for Azoxystrobin and Iprodione removal from water. Cell-MG membrane was structurally and morphologically characterized using FT-IR and FE-SEM techniques. The influences of operational parameters, i.e. pH, contact time, temperature, and the mass of adsorbent on adsorption and kinetics were studied in a batch system. The calculated capacities of 35.32 and 30.16 mg g-1 for Azoxystrobin and Iprodione, respectively, were obtained from non-linear Langmuir model fitting. Weber-Morris model fitting indicates the main contribution of intra-particle diffusion to overall mass transport resistance. Thermodynamic data indicate spontaneous and endothermic adsorption. The reusability of adsorbent and results from wastewater purification showed that Cell-MG could be used as general-purpose adsorbent. The adsorbent/adsorbate surface interaction was considered from the results obtained using density functional theory (DFT) and calculation of molecular electrostatic potential (MEP). Thus, a better understanding of the relation between the adsorption performances and contribution of non-specific and specific interactions to adsorption performances and design of novel adsorbent with improved properties was deduced.