(512e) Batch and Packed-Bed Adsorption Study for the Removal of Dye from Textile Wastewater Using in-House Prepared Silica-Based Nanosorbcats: Kinetics and Computational Modeling

The worldwide shortage of fresh water and the huge competing demands from variety of users stimulates an urgent need for finding alternative cost-effective and environmentally friendly wastewater treatment processes. For instance, synthetic dyes wastewater discharged from the textile and dyestuff industries poses an environmental alert since these organic pollutants are toxic to many aquatic and non-aquatic living organisms. In addition, some of these pollutants are non-biodegradable, and thus, they will exist for a long time in the environment, which may cause a real challenge to the conventional wastewater treatment processes. Accordingly, innovative and environmentally sound techniques are needed. The application of nanoparticle technology as adsorbents and catalysts (nanosorbcats), whether as a standalone or as an enabling technology, in cleaning up wastewater has recently received great attention. This is because of the unique chemical and physical properties of nanoparticles in comparison with their counterparts, which make them superior to the conventional adsorbent/catalysts.

Accordingly, the present study investigated the employment of newly in-house prepared silica-based nanosorbcats functionalized with active species for cleaning up textile wastewater. A facile co-precipitation synthesis route was used to prepare those nanosorbcats, which were characterized by different characterization techniques like XRD, BET, TPD, TPR, HRTEM and zeta potential. The prepared nanosorbcats were employed for the adsorptive removal of cationic and anionic dyes from synthetic and real textile wastewater. Batch adsorption studies were performed for kinetics and equilibrium modeling on the removal of different dyes from wastewater. The operating variables studied were contact time, initial dye concentration, and solution pH. Results showed an optimum pH value, where the maximum removal of dye was achieved. The experimental adsorption data have been modeled using Sips and BET adsorption isotherm models. In addition, a computational modeling on the selected model compounds was carried out to understand the adsorption mechanism on the prepared nanosorbcats. Breakthrough capacities were also investigated in a packed-bed column study. The most successful silica-based nanosorbcats in cleaning up the real textile wastewater in the batch experiments were prepared in extrudate form and used in up-flow packed-bed adsorption experiments. The effects of the influent concentration, flow rate, and bed height were investigated. Breakthrough time and adsorption capacity of the packed-bed increased with increasing bed height, whereas decreased with the increase in influent initial concentration and flow rate. The reliable results of this study will be elaborated and discussed further during the presentation.