Comparative study of raw and microwave irradiated industrial solid waste as adsorbent for the removal of methylene blue from its aqueous solution

Raw shot blasting dust (SBD) has been collected from a foundry and then treated in a microwave (MWSBD). Both raw and treated samples are employed as adsorbents for adsorption of methylene blue (MB) from its aqueous solution. Composition of raw SBD and MWSBD is studied through wet analysis. Fourier transform infrared spectrophotometry analysis proves the presence of groups like Si-O-Si, Si-OH, iron oxide and traces of ammonia in adsorbent. Surface morphology of adsorbent is studied through scanning electron microscopy and surface area analysis is conducted to evaluate surface area, total pore volume and pore diameter. The effect of pH, initial dye concentration, adsorbent dosage and contact time has been studied and optimum experimental conditions are obtained. Results reveal that as the amount of adsorbent increases, the percentage removal of the dye also increases. The adsorption of MB dye onto raw SBD and MWSBD follows pseudo second order kinetics and intra-particle diffusion model. Study on the dye by both the adsorbents fits the Freundlich, Langmuir and Dubnin- Radushkevich isotherms well. The present study confirms the potentiality of an abundant low cost solid waste material and its availability for the removal of basic dyes from aqueous solution.