Application of Agricultural Wastes for Cationic Dyes Removal from Wastewater

Abstract

Wastewater effluents containing cationic dyes have significant impact on our environment due to their carcinogenic effects. Dyeing wastewater contains complex chemical compositions that are poisonous to human and pose a threat to aquatic organisms. Many traditional approaches have failed to treat dye-contaminated water because they are ineffective or cost prohibitive. Due to its low cost, uniform design, and ease of use, adsorption is gaining popularity in pollutant control. In physiochemical treatment schemes for environmentally friendly remediation of such toxicants, agricultural-based products are used as adsorbents and co-substrates. The effectiveness of agro-biomass/by-products from plants (leaves, seed/flower, stem, and root) as pristine adsorbents (raw biomass) or modified biomass for direct dye removal, as well as their function as co-substrates to promote the biodegradation/decolorization of cationic dyes, is the subject of this chapter. The chapter also explained how operating conditions, kinetics, and isotherm models can be used to better explain the adsorbent activity and adsorption mechanisms. We review (1) general properties of cationic dyes, (2) current knowledge on the removal of dyes, (3) adsorption of cationic dyes using different bio adsorbents, (4) factors affecting dyes sorption process, Because of its high adsorption performance, bio adsorbent has been widely used as an adsorbent, but because of its high cost of use, many researchers have looked for low cost, locally available substitute adsorbents to make the adsorption process more commercially viable, we present a selection of studies on the removal of the most widely identified cationic dyes from agricultural waste, primarily leaves, stems, roots, and flower/fruit. Among different types of cationic dyes, Methylene blue is the most gaining attention while the other part of agro waste, (flower, fruit peel & seed) is the most used and gave the maximum yield. Adsorption reviews have shown that the adsorption procedure is strongly dependent on parameters such as contact time, adsorbent dosage, pH, and initial concentration of the dye, temperature and pressure, functional group, and pore volume and particle size in aqueous solution.