PHOSPHORUS REMOVAL EFFICIENCY OF MAGNESIUM CHLORIDE MODIFIED PINEWOOD SAWDUST FROM AQUEOUS SOLUTION

Abstract

Water bodies are polluted by phosphorous due to several reasons, including domestic and agricultural wastewater being discharged into water sources. Wastewater leads to accelerated eutrophication processes that damage marine ecosystems, create problems for the availability of drinking water, and affect areas with scarce resources. To address this issue, this study investigates the phosphorus, present as phosphate (PO43-) in water, removal efficiency of magnesium (Mg) modified raw pinewood sawdust as a feasible, low-cost biomass-based adsorbent. Raw pinewood sawdust was powdered and treated with MgCl2 salt at different concentrations to induce positively charged surface sites and enhance their porosity, followed by washing and drying to obtain stable granular material. Batch adsorptions were done under varying volumes of MgCl2 salt used for treating the sawdust dosages of adsorbent to evaluate the removal efficiency for phosphate of the biosorbents and their adsorption capacity. The MgCl2 modified sawdust showed an increase in adsorption of phosphate content compared to untreated biomass. Samples used for the test were raw pinewood sawdust (unmodified) along with 1:10 w/v and 1:20 w/v of both 0.1M and 2M MgCl2 modified pinewood sawdust. The highest removal efficiency of around 48% was found for the sample treated using 1:20 w/v 2M MgCl2 (2-Mg-PS20) while others showed slightly lower removal with unmodified raw pinewood sawdust showing the least value. The FTIR analyses were carried out for the samples that confirm the successful MgCl2 modification of raw pinewood sawdust thus showing the highest peaks at, 1000 cm-1, 1550 cm-1 and 3300 cm-1. Overall, the findings show that Mg modified raw pinewood sawdust is a reliable, scalable, and eco-friendly option for phosphate removal from water, that can help support circular economy approaches that can accompany the biomass waste valorization with nutrient pollution control. This study explores a low-cost approach by using timber industry by-product that can help address the targets of SDG 6 (Clean Water and Sanitation).