Adsorbents Characterization and Effect of Reaction Indices on The Uptake of Cadmium (II) and Chromium (VI) Ions From Wastewater

Abstract

The effect of reaction variables on the uptake of heavy metals from wastewater using modified chitosan and plantain peels carbon based adsorbents was explored in this study. Plantain peels were carbonized, activated with phosphoric acid and the activated carbon was separated into various proportions and impregnated with various percentages of chitosan to make the composite biosorbents. Deproteinization, deminerization, and deacetylation techniques were used to extract chitosan from a snail shell. Fourier transform infrared (FTIR), energy dispersive X-ray (EDAX), X-ray diffraction (XRD), scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) techniques were used to analyze the adsorbents. Effects of process parameters: pH of wastewater, adsorbent dosage, temperature, initial concentration and contact time were determined. In the blending ratios of the biosorbents, 75% oxalic acid modified chitosan-25% activated plantain peel (CH_T-APP₅) was best blend and the optimum process variables for the removal efficiency were time (60-65mins), adsorbent dosage (2-2.125g/dm³), pH(6-6.5), initial concentration of wastewater(20-85mg/dm³) and temperature (308-325K). The results obtained showed that the maximum adsorption capacities of 90.9090, 55.5556 and 142.8571mg/g for Cr(VI) while 62.500, 83.3333 and 43.4783mg/g Cd(II) were obtained for CH_T, APP₁ and CH_T-APP₅ respectively. The results showed that blends have the potential to be used as alternative efficient low-cost biosorbent in the removal of heavy metals from wastewater.