OPTIMIZATION OF BORON REMOVAL FROM AQUEOUS SOLUTION VIA ADSORPTION USING COMPOSITE BEADS OF MANGROVE BARK, ALGINATE AND ZEOLITE

Abstract

 The presence of boron beyond the allowable limit in water bodies can pose a dangerous risk to all living organisms. In order to increase the adsorption capacities of composite beads of mangrove bark, alginate and zeolite (MAZC) to remove boron from aqueous solution, pretreatment of mangrove bark using sodium hydroxide solutions at a temperature of 60°C was conducted. The surface characterizations of the beads were conducted using Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett Teller (BET) and scanning electron microscope with energy dispersive X-ray spectroscopy (EDX) before and after boron adsorption. The results showed that the BET surface area of MAZC beads increased due to modification of the mangrove bark during pretreatment process. The effects of pH, temperature, adsorbent dosage and contact time on the boron uptake were then evaluated using batch studies. It was found that the maximum adsorption of boron was 83.3% occurred at pH 5, 24 h contact time, 12 g of adsorbent dosage and at a temperature of 27°C. Thermodynamic studies indicated the spontaneous and exothermic nature of adsorption process. Langmuir isotherm model best described the experimental adsorption data with maximum adsorption capacities of 6.964 mg/g. The kinetic data were best described by the pseudo-second order model (R2 = 0.9998). These results indicate that the pretreatment of mangrove bark can optimize the removal of boron from aqueous solution.