Ecology, Environment and Conservation Paper

STUDY ON TREATED FLY ASH AND CLADODES OF OPUNTIA FICUS INDICA AS LOW-COST DYE ADSORBENTS

Bhavesh Choudhary, Yogesh Choudhary and Shailaja Palan

Abstract

Textile industries discharge wastewater containing harmful dyes into the environment, causing pollution. The conventional methods for treating dye-containing wastewater are expensive and beyond the financial reach of small-scale textile industries. This study explores the use of two low-cost adsorbents, namely fly ash and Opuntia ficus indica, as alternatives to conventional methods. The adsorption efficiency of these adsorbents, both individually and in combination, was evaluated against crystal violet and malachite green in aqueous solution. Fly ash was treated with HCl and microwave irradiation, and Opuntia ficus indica was activated chemically using NaOH and NaClO. The adsorption capacity of the adsorbents varied with the preparation conditions and the type of dye. Microwave-treated fly ash exhibited the highest adsorption capacity, achieving a 95.2% reduction in 0.05% crystal violet. However, it only showed a 19% reduction in 0.05% malachite green. Opuntia ficus indica activated with NaOH exhibited the highest adsorption capacity for both crystal violet and malachite green, achieving 50.8% and 44.5% reductions, respectively. The combination of treated fly ash and treated Opuntia ficus indica exhibited the highest reduction in 0.5% crystal violet (40.5%) and 0.02% malachite green (93.52%). The adsorption capacity of the combination was better than the individual samples of treated fly ash and treated Opuntia ficus indica for malachite green. These findings suggest that the combination of treated fly ash and treated Opuntia ficus indica could be a promising low-cost alternative for treating dye-containing wastewater in small-scale textile industries.