Use of Cordia myxa seed biomass as biosorbent for methylene blue dye removal from wastewater

Abstract: Management of agriculture and horticulture waste biomass are of great concern in achieving circular economy and sustainable development goals. Use of plant biomass in sorption and biosorption is being explored for wastewater remediation cum agricultural and horticultural solid waste management. This study presents the use of the seeds of lasura/lasoda (Cordia myxa) as biosorbent for azo dye Methylene Blue (MB) from wastewater. The proximate and ultimate characterization of Cordia myxa seed powder (CMSP) was carried out for the bulk and surface characterization. Batch biosorption experiments were performed changing the range of parameters i.e. initial concentration of MB (C₀), and contact time (t) at room temperature. In order to know the nature and behaviour of biosorption process, equilibrium isotherms and kinetics were deciphered by employing commonly used models i.e. Langmuir, Freundlich, PFO (pseudo first order) and PSO (pseudo second order). The maximum MB dye uptake capacity of CMSP was determined as 21.93 mg/g at room temperature (398K). The Freundlich isotherm model and pseudo second order kinetic models were found to be the best fit (R² >0.99) for the biosorption process. This study shows the applicability of Cordia myxa seed waste as low-cost treatment of dye wastewater.