Preparation Of Anionic Gemini Surfactant And Its Remediation Of Heavy Metal Contaminated Soil

Due to the complexity of chemical behaviors and ecological effects,heavy metals in soil have been the subject of continuous research in environmental science in recent years.It has become a huge problem for many environmental protection workers to seek a simple,efficient and economic soil heavy metal remediation technology.In many soil heavy metal remediation technologies,heavy metals are transferred to the soil solution by chemical leaching,and then heavy metals in the soil solution are adsorbed by chemical precipitators and adsorbents.Heavy metals in soil can be removed through a series of systematic and complete chemical removal processes.Two kinds of products,carboxylic acid and phosphoric acid anionic Gemini surfactant,were synthesized and characterized by elemental analyzer and nuclear magnetic resonance hydrogen spectrum.The synthetic carboxylic acid and phosphoric acid anionic Gemini surfactants were selected as leaching agents to repair Pb,Cr,Cu and Cd in heavy metal contaminated soil samples.The removal of heavy metals from the soil was investigated by means of shock and ultrasonic leaching,including concentration,pH,soil-liquid ratio,shock and ultrasonic time.The morphology of heavy metals in soil before and after treatment was determined by Tessier method,and the removal mechanism of heavy metals by carboxylic acid and phosphate anion Gemini surfactants was determined by sem.Select commercially available chemical precipitators(quicklime and sodium phosphate)and adsorbents(activated carbon)to remove heavy metal ions transferred to the soil solution.The experimental results showed that :(1)the critical micelle concentration of the synthesized carboxylic acid anionic Gemini surfactant was 0.1mmol/L,and the minimum interfacial tension was 1.19 mN /m;the critical micelle concentration of phosphate anionic Gemini surfactant was 0.001mmol/L,and the minimum interfacial tension was 0.85 mN /m.(2)Carboxylic acid anionic Gemini surfactant has an obvious removal effect on heavy metals in the soil.When the concentration of carboxylic acid anionic Gemini surfactant is 5mmol/L,the pH is 2.5,the soil-liquid ratio is 1:10,the removal effect of heavy metal Pb is the best under the condition of shock for 24 h or ultrasound for 90 Min,which is 48 times of the removal effect of washing shock.When the concentration of carboxylic acid anion Gemini surfactant was 5mmol/L,the pH was 7,the soil-liquid ratio was 1:20,the removal effect of heavy metal Cr,Cu and Cd was the best under the condition of shock for 24 h or ultrasonic for 90 Min,which was 1.7 times,91 times and 8.6 times of the removal effect of rinse shock,respectively.when the concentration of phosphoric acid anionic Gemini surfactants as the tendency for 5 mmol/L,pH of 7,soil 1:12 ratio of liquid,volatile time 24 h or 150 min under the conditions of ultrasonic effect is best,to eliminate the heavy metal Cr 2 times that of removing water leaching shock;When the concentration of phosphoric acid anionic Gemini surfactants as the tendency for 5 mmol/L,pH 2.5,soil liquid ratio for 1:12,24 h or ultrasonic oscillation time under the condition of 150 min of removing heavy metal Pb,Cu and Cd in the best,removing water leaching shocks are 20 times,2 times and 4.4 times.(3)By carboxylic acid and phosphoric acid anionic Gemini surfactant treatment before and after the morphological analysis of heavy metals to exchange state,carbonate combined with iron and manganese oxide combined states of heavy metals removal effect is good.Carboxylic acid and phosphoric acid anionic Gemini surfactants removal mechanism of heavy metal polluted soil can be summarized as complexation,ion,adsorption and solubilization.(4)using sodium phosphate chemical precipitation agent for 3 g,the quality of the pH for 9-10,the temperature of 35 ?,the heavy metal Cu removal rate is 90%;The quality of the sodium phosphate is 1.5 g,pH of 9 to 10,the temperature of 40 ?,the removal rate of heavy metal Pb 99%,;Quick lime quality is 1.5 g,pH of 11-11.5,the temperature of 35 ?,the removal rate of heavy metal Cr is 99%;Quick lime quality is 1.5 g,pH 11.5,the temperature of 35 ?,the heavy metal Cd removal rate of 90%.Using carboxylic acid and phosphoric acid anionic Gemini surfactants as drench lotion can effectively remove heavy metal ions in the soil,through its complexation mechanism such as transferred to the heavy metal ions in soil solution using precipitant and adsorbent to remove,effectively solve the pollution of heavy metals in aqueous solution.