Wheat bran
Wheat bran, a by-product of wheat milling industries proved to be a good adsorbent for removal of many types of heavy metal ions such as Pb(II), Cu(II) and Cd(II). The application of a strong dehydrating agent like sulfuric acid (H2SO4) can have a significant effect on the surface area of the adsorbent, which eventually results in better efficiency of adsorption of copper ions as reported by Özer et al. (2004). It was found that upon treatment with sulfuric acid, wheat bran had a much higher surface area. The authors suggested that acid treatment caused changes in surface area by increasing the conversion of macropores to micropores. Maximum adsorption capacity for Cu(II) ions was reported as 51.5 mg g−1 (at pH 5) and equilibrium time of adsorption was achieved in 30 min. Özer and Pirinççi (2006) conducted a study on the removal of lead ions by sulfuric acid treated wheat bran. It was reported that maximum lead removal (82.8%) occurred at pH 6 after 2 h of contact time. Three isotherm models were analyzed for determining the maximum adsorption capacity of wheat bran particularly Langmuir, Freundlich and Redlich-Peterson. Based on the non-linear plots, it was found that adsorption fitted well to the Redlich-Peterson than Langmuir and Freundlich models. The Langmuir plots indicate that maximum adsorption capacities increased with an increase in temperature (79.37 mg g−1 at 60 °C and 55.56 mg g−1 at 25 °C). The decrease in the values of ΔG° suggests that adsorption was more favourable at higher temperatures and adsorption was endothermic in nature. The kinetic study showed that lead adsorption could be described well with nth-order kinetic model. Özer (2006) also examined the sulfuric acid treated wheat bran for cadmium ion removal from aqueous solution. After 4 h of contact time, the maximum adsorption capacity that could be achieved for cadmium was 101 mg g−1 at pH 5. Therefore, in general the order of maximum removal of the above three metals follows: Cd(II) > Pb(II) > Cu(II).
รำข้าวสาลีWheat bran, a by-product of wheat milling industries proved to be a good adsorbent for removal of many types of heavy metal ions such as Pb(II), Cu(II) and Cd(II). The application of a strong dehydrating agent like sulfuric acid (H2SO4) can have a significant effect on the surface area of the adsorbent, which eventually results in better efficiency of adsorption of copper ions as reported by Özer et al. (2004). It was found that upon treatment with sulfuric acid, wheat bran had a much higher surface area. The authors suggested that acid treatment caused changes in surface area by increasing the conversion of macropores to micropores. Maximum adsorption capacity for Cu(II) ions was reported as 51.5 mg g−1 (at pH 5) and equilibrium time of adsorption was achieved in 30 min. Özer and Pirinççi (2006) conducted a study on the removal of lead ions by sulfuric acid treated wheat bran. It was reported that maximum lead removal (82.8%) occurred at pH 6 after 2 h of contact time. Three isotherm models were analyzed for determining the maximum adsorption capacity of wheat bran particularly Langmuir, Freundlich and Redlich-Peterson. Based on the non-linear plots, it was found that adsorption fitted well to the Redlich-Peterson than Langmuir and Freundlich models. The Langmuir plots indicate that maximum adsorption capacities increased with an increase in temperature (79.37 mg g−1 at 60 °C and 55.56 mg g−1 at 25 °C). The decrease in the values of ΔG° suggests that adsorption was more favourable at higher temperatures and adsorption was endothermic in nature. The kinetic study showed that lead adsorption could be described well with nth-order kinetic model. Özer (2006) also examined the sulfuric acid treated wheat bran for cadmium ion removal from aqueous solution. After 4 h of contact time, the maximum adsorption capacity that could be achieved for cadmium was 101 mg g−1 at pH 5. Therefore, in general the order of maximum removal of the above three metals follows: Cd(II) > Pb(II) > Cu(II).
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