Sorption Study Of Thiophene On Layered Double Hydroxide

Thiophene compounds is a kind of typical organic sulfur compounds, which consist abundantly in many fields, such as fuels, industrial effluents. Thiophene compounds which consist in the industrial wastewaters are toxic substances and have corrosive action. Thiophene compounds in transportation fuels are a significant source of atmospheric pollution by sulfur oxides. There will be a great harm to the health of human beings and the environment, if thiophene compounds not be eliminated.In our research, the Zn2Al-CO3 LDH was synthesized by using a new method involving separate nucleation and aging steps, and the dodecylsulfate intercalated hydrotalcite (SDS-LDH) was synthesized by using the co-precipitation method. The two materials have been used to remove thiophene from aqueous solution, It was noticed that the adsorption behavior of thiophene on them was very different. The adsorption behavior of Zn2Al-CO3 LDH was obviously influenced by the pH, with the best removal efficiency in the pH range of 6.00 to 8.00. When the temperature was 25℃, the initial thiophene concentration was 800 ppm, the highest removal rate was 88.7% and the maximum value of adsorption capacity was 354.8 mg/g. For SDS-LDH, the adsorption process was found to be pH-independent, which could be used in a wide pH range. When the temperature was 25℃, the initial thiophene concentration was 800 ppm, the highest removal rate was 91.4% and the maximum value of adsorption capacity was 146.24 mg/g. The adsorption kinetics research of the two materials indicated the chemisorption mechanism being the rate-determining step, not just diffusion process.The Zn3Al-LDH and Ni3Fe-LDH were synthesized by using a new method involving separate nucleation and aging steps. These materials have been used to remove thiophene from n-heptane solution. It was observed that Ni3Fe-CO3 LDH was the best adsorbent, because it had the highest removal rate and the maximum value of adsorption capacity. So we have made further researches on adsorption of thiophene from n-heptane solution by Ni3Fe-CO3 LDH. The results indicated that the highest removal rate was reached after 120 min at 40℃. The highest removal rate was 26.8% and the maximum value of adsorption capacity was 8.62 mg/g. The optimum dosage for Ni3Fe-CO3 LDH was 20 g·L-1 respectively. The regeneration of adsorbent was also studied. The results showed that 50℃and 60 min was the best condition for regeneration of adsorbent. The adsorption capacity had only reduced a little when regeneration three times.