Study On Ni And Pb Containing Wastewater Treatment With Gemini Micellar-enhanced Ultrafiltation

As is known to all,heavy metals such as nickel and lead have great harm to the human body.It is effective way of solving the nickel pollution and lead pollution to discharge the nickel-containing and lead-containing wastewater after treating it with proper means until it reached the corresponding regulatory standards.So far some conventional treatment methods include chemical precipitation,chemical oxidation,ion exchange,adsorption,electrochemical and flotation,etc was widely used to treat with the nickel-containing and lead-containing wastewater.However,these methods mostly have some shortcomings such as: harsh treatment conditions,process complexity,energy consumption and so on.In recent years,the micellar-enhanced ultrafiltration(MEUF)has exhibited some significant advantages in the field of waste water treatment.Nevertheless,the amount of surfactant used in MEUF is large,and its secondary pollution caused by the discharged surfactant was too severe to be neglected.These weaknesses greatly limited its development.An an anion Gemini surfactants G1 has been synthesized and the GMEUF of Pb2+ or/and Ni2+ using G1 as surfactant was studied.The utilizing of G1 in GMEUF may solve the problems emerging in the conventional MEUF such as large dosage of surfactant and serious secondary pollution.The investigation in this thesis has focused on optimal process parameters and comparation of GMEUF with G1 with the conventional MEUF.According to the experimental results,make an objective evaluation of the merits and faults of the GMEUF method.The major contents are as below:(1)The Gemini surfactant G1 was synthetized.The purity and structure information were characterized.The results showed that the synthetized compound was the target compound with high purity.(2)The conductivity method was used to measure the critical micelle concentration(CMC)of G1 and the concentration of 1.298 × 10-4 mol/L was conformed as the CMC of G1,which approximately is the 1% of the CMC of conventional anionic surfactant sodium dodecyl sulfate(SDS)(CMC = 7.770 × 10-3 mol/L).(3)Treating with nickel-containing wastewater using MEUF with self-synthesized Gemini surfactant G1 was investigated.The results show that the optimal process parameters can be confirmed as feed G1 concentration of 1 CMC(1.298 × 10-4 mol/L);operating time of 20 minutes,operation pressure of 0.07 MPa;and pH of 5.20;Under this optimized process parameters,within 5 times analyzed,the relative standard deviations for retention and recovery ratio were no more than 5%,which highlights the high reproducibility of GMEUF process.Under the same process parameters,comparison with the conventional MEUF with SDS,the dosage of surfactant decreased 100 times;retention of surfactant rised 1.6 times and discharge of surfactant decreased 250 times.(4)Treating with nickel and lead-containing mixed wastewater using GMEUF with self-synthesized Gemini surfactant G1 was investigated.The optimal process parameters can be confirmed as feed G1 concentration of 1.5 CMC(1.947 × 10-4 mol/L);operating time of 20 minutes;operation pressure of 0.07 MPa and pH of 5.20;.Under this optimized process parameters,within 5 times analyzed,the relative standard deviations for retention and recovery ratio were no more than 5%,which highlights the high reproducibility of GMEUF process.Under the same process parameters,comparison with the conventional MEUF with SDS,the dosage of surfactant decreased 60 times;retention of surfactant rised 1.5 times and discharge of surfactant decreased 160 times.This study will be a preliminary attempt on treatment of metal ion pollutant with the GMEUF methodThe study of this subject,not only is a preliminary attempt on treatment of single heavy metal wastewater using GMEUF,but also is an exploration to treat with mixed heavy metal wastewater application field using GMEUF.