Synthesis of zeolite from marble powder waste: a greener approach and its application for the removal of inorganic metals from wastewater

Abstract

The wastewater containing heavy metals, produced at various stages of operation in textile, printing, plastic, and paper-making industries, pose major hazards to the environment and the public health. Therefore, it is necessary that the pollutants should be treated before discharge by using highly efficient adsorbents. Zeolite is a potential material and can conveniently be processed as adsorbents for the removal of environmental pollutants. A wide range of commercial zeolite has been marketed but due to high cost it is of limited use. The present research offers a green approach for the application of zeolite synthesized by using marble powder waste as a precursor. The significance rests on the conversion of waste into a useful adsorbent marble zeolite (MZ). Zeolite is an environmental friendly, novel, and cost-effective adsorbent. In the current study, remediation of heavy metals in industrial wastewater is done using zeolite. The marble waste contains metals like Zn, Ni, Pb, Cr, Cd, and Cu in it and this waste itself also used as an adsorbent for removal of metals and its efficiency is ≥85%. The batch method has been employed for metal removal using different standard solutions at concentrations of 50–200 mg/L of individual metals (Zn, Ni, Pb, Cr, Cd, and Cu). The optimum removal efficiency is determined at 50 mg/L and the results depicted the performance of MZ (1 mg/kg) in removing inorganic pollutants upon adsorbate–adsorbent contact for 30 min, at lower dose of MZ. It was also found that the higher the induced concentration, the lesser the removal efficiency. It may be due to the limiting factor of adsorbent dose. The adsorbent was also applied on industrial effluents taken from textile and plastic factories at optimum studied conditions. The removal mechanism of metal ions followed adsorption and ion exchange processes. These results show that the MZ holds a great potential to remove heavy metals from industrial wastewater. The study recommends the reutilization of MZ as a potential adsorbent, which can greatly enhance the sustainability of useful resources.

Keywords:

• Pollutants
• Adsorbents
• Zeolite
• Marble powder
• Synthesis
• Sustainability

Acknowledgments

The research was financially supported by the Grant PPP (PG008-2013B), (PG138-2014B) and (PG133-2014B).