Reforming of graphite oxide from agro-waste by incorporating nanosilica for the remediation of nitrate and phosphate anions from wastewater

Abstract

Graphite oxide obtained from the oxidation of sawdust with (0.5 wt%) was immobilized into silica to improve the effectiveness of the silica phase toward depollution. The functional interaction profiles were assessed using XRD and SEM performances. The excess loading of graphite oxide percent encouraged the aggregation of incorporated silica molecules, forming the so-called “colonies”. Such colonies caused marked exfoliation of graphite oxide layers in the as-designed silica @graphite oxide hybrid materials and considerable coalescence of graphite oxide in a silica matrix. The as-designed silica @(0.01) graphite oxide nanocomposites showed pronounced sorption competences for PO4-3 (95%), not the same for NO3- (72%). Such depollution behavior is governed by the interaction profiles including the incorporated graphite oxide and “silica colonies”. The fitness of the kinetic models was ranked as pseudo-first order. The values of ΔHo = 0.824 and 3.58, So = 0.109 and 0.116, and Go = -33.45 to -36.7 kJ/mole for phosphate and nitrate, respectively. The estimated data point to endothermic, spontaneous adsorption in nature.