Removal of methylene blue azo dye from aqueous solution using biosorbent developed from floral waste

Abstract

Aim: The present study was carried out to prepare biosorbent from temple floral waste (Tagetes erecta) by pyrolysis and chemical activation method for removal of methylene blue dye from aqueous solution. Methodology: Floral waste of Tagetes erecta collected from the temples were segregated, washed and dried to form biochar by direct pyrolysis and chemical activation method. Followed by physio-chemical analysis of biosorbents the most efficient biochar was selected for the removal of methylene blue dye from aqueous solution. The adsorbent efficiency and percentage removal of methylene blue dye was studied using various doses of biochar (10, 20, 30, 40, 50, 60, and 70 mg 100 ml-1,), effect of pH (2.0 to 4.0, 6.0 to 8.0, and 10.0 to 12.0) and effect of contact time etc. Results: The comparative physio-chemical analysis of the bio chars suggested that the activated charcoal made from temple flower waste by the direct pyrolysis method showed better performance, with its low moisture content (5.3%), low ash content (4.3%), higher yield, larger surface area, and higher porosity (65.3%) as compared to the biochar obtained from chemical activation. The percent adsorption significantly increased (p<0.05) from 76% to 87.0% on increasing biochar dose from 10.0 to 70.0 mg 100 ml-1. On increasing the pH of the solution from 4.0 to 6.0, Methylene blue removal significantly increased (p<0.05) from 88.0% to 91.0%. Interpretation: It is possible to manage floral waste from temples in a sustainable and environmentally responsible manner by converting it into biochar and using it for the treatment of waste water in order to eliminate hazardous dyes. Key words: Activated carbon, Azo dye, Bioremediation, Biochar, Floral waste, Methylene blue