Rice husk ash derived nanocrystalline ZSM-5 for highly efficient removal of a toxic textile dye

Abstract

Synergistic solution of two different environmental issues such as solid waste management and wastewater treatment is not just a sustainable solution but also adds to circular economy. In this study, a novel nano ZSM-5 zeolite (nZSM-5) was synthesized from agro-waste rice husk ash by two-step method for removal of industrial toxic dye crystal violet (CV) from water using ultrasonic-assisted adsorption process. The physico-chemical properties of as-synthesized nZSM-5 was examined by means of TEM, XRF, FESEM, XRD, FTIR, and BET analysis. Surface area, average pore volume, average crystal size, and product yield of nZSM-5 were found as 608.93 m2/g, 0.245 cm3/g, and 8.5 nm, 87% respectively. Also, from FESEM analysis, the average particle size was found to be 32.42 nm. Effect of solution pH (3–11), sonication time (0–60 min), adsorbent dose (50–250 mg/100 ml), and initial CV dye concentration (25–125 mg/L) on nZSM-5 was analyzed in ultrasound-assisted adsorption process. Pseudo-second order kinetic (R2 = 0.994) model and Langmuir isotherm (R2 = 0.991) model were best fitted for the adsorption of CV on nZSM-5 with maximum Langmuir adsorption capacity of 125.43 mg/g. The removal efficiency of nZSM-5 zeolite for CV dye was estimated as 99.99%. This study suggests that the synthesized novel nZSM-5 zeolite is a highly efficient adsorbent for CV dye under ultrasonication.

Keywords

• Rice husk ash
• Nano-ZSM-5
• Crystal violet
• Adsorption kinetics
• Adsorption isotherm