ANALYSIS OF ADSORPTION PERFORMANCE OF LATERITIC SOIL GEO-POLYMER COMPOSITE DEVELOPED AS A BARRIER IN A SANITARY LANDFILL

Abstract

Dump site is a threat to the environment, surface and underground water and has been a major concern in environmental sustainability. This study focused on the effects of different doses of metakaolin-based geo-polymer (0, 5, 7.5, and 10 %) on the adsorption of the heavy metals in the soil-geopolymer: leachate solution (1:4) for their optimal contact times. The mixture was filtered and the concentration of residual pollutants in the municipal solid waste leachate was measured after the corked conical flasks were shaken at 150 rpm using an orbital shaker. As the dosage of the adsorbent was increased, the content of heavy metals in the three leachate samples(A, B ,C) decreased gradually as follows: At 0% dosage the concentration are Pb(0.512, 0.493 and 0.43mg/l), Zn(0.412, 0.191 and 0.397mg/l) and Cu(0.091, 0.133 and 0.126mg/l) for Sample A, B and C and at 10% Pb(0.315, 0.325 and 0.253mg/l), Zn(0.024, 0.031 and 0.028mg/l) and Cu(0.022, 0.003 and 0.009mg/l) for samples A, B and C respectively, resulting to the corresponding increase in the percentage removal thus: At 0% dosage the removal efficiency are Pb(19.24%, 26.98%, and 23.63%), Zn( 34.98%, 26.98% and 32.98%) and Cu (81.67%, 63.08% and 70.26%) for sample A, B and C respectively and at 10% dosage the removal efficiency are Pb(50.32%,51.49% and 55.38%), Zn(96.26%,94.97% and 95.25%) and Cu(96.26%, 99.22% and 97.85%) for sample A, B and C respectively after treatment. This is in conformity that Metals adsorption efficiency and capacity increases with increase in adsorbent dose. The adsorption capacity of the lateritic soil -geopolymer composite increases with increase in dosage as witnessed. This proves that during the adsorption reaction, the adsorption sites stay unsaturated while the number of sites available for adsorption site grows when the adsorbent dose is increased. It is recommended to explore different ratios of lateritic soil and geopolymer to determine the optimal composition for enhanced mechanical strength and sorption capacity, potentially leading to even more effective landfill liner materials.