Utilization of silica gel waste for adsorption of cationic surfactant and adsolubilization of organics from textile wastewater: A case study

The use of silica gel waste (SGW) as an adsorbent was found to be a very attractive alternative for removal of cationic surfactant (CS) from industrial (textile) wastewater. In the present work, the actual textile wastewater containing 362 mg/l CS (in terms of CTAB) was treated by SGW in both batch and continuous modes. In batch mode, the optimum adsorbent dose and equilibrium time were found to be 10 g/l and 30 min respectively. Under optimized conditions, high removal efficiency of CS was achieved (~ 87%) and subsequent solubilization of other organic pollutants was found to occur through adsolubilization. The adsorption followed the Freundlich isotherm model. The breakthrough and exhaust times were found to be 6.5 and 13 h respectively for a column of depth 50 mm, maintaining the loading rate at 1.22 m3/m2/h. The value of adsorption rate coefficient (K) and adsorption capacity coefficient (N) were found out. Regeneration of SGW after its exhaustion was efficiently done using 18% hydrochloric acid. The use of a solid waste of a factory as an adsorbent for removal of cationic surfactant and subsequent adsolubilization of organics made the process very cost effective alternative for textile wastewater treatment.

Research highlights
► The silica gel factory waste was used for treatment of real textile wastewater.
► The study was carried out in both batch and continuous modes.
► The waste removed surfactants and organics through adsorption and adsolubilization.
► The removal for wastewater was higher than distilled water spiked samples.
► Use of an industrial waste to treat another made the process cost-effective.