Study On The Electrosorption Desalination Technology In The Treatment Of Secondary Effluent Of Sewage Of Petrochemical Enterprises

Freshwater is a very precious resource, which has become an important constrainingfactor of China,s economic development. Therefore, the increase in the rate of wastewaterreuse is the main way to solve the shortage of freshwater resources. Salinity is a majorlimitation indicators, when Industrial wastewater is used for circulating cooling water,Therefore, the waste water desalination is a necessary process steps in wastewater reuse.Electrosoption technology is a new desalination technology, which has high desalination rate,low power consumption, without chemical regeneration and anti-pollution ability. Themechanism of Electrosorption desalinization is that an appropriate voltage is applied to thepole plate, so that the contact surface of the plate with the solution would produce andouble-layer, then Ions which is tractied by surface charge migrate to the double-layer andstore in the double-layer at the surface of electrode, so that to achieve the purpose ofdesalting.Study the optimum operating parameters, desalting performance and desalinization ofelectrosorption desalination technology with artificial water in previous experiments. Finally,to verify the secondary treatment of sewage water depth processing purifying effect ofLanzhou Petrochemical Enterprises achieve the purpose of replacing reverse osmosis in thereverse osmosis-ion exchange resin-a mixed ion-exchange bed process as an ion exchangeresin in the pretreatment process.The main research content and innovation thesis of paper are summarized as follows:(1) The plate voltage range of1.3V~1.6V. The removal rate of ion with the increases ofthe voltage, but the energy consumption per ton water increases. So the appropriate voltage is1.5V.(2) Influent concentration within the range of250mg/L~850mg/L, mass of sorption ishigher under higher concetration of solution. However, when the concentration reaches acertain level, the adsorption capacity of the electrosorption reachs stabilized value. The ionconcentration of influences has a little effect on the sorption of the double-layer.(3) The influent flow range15ml/min~30ml/min, when wastewater flow increases, thelinearity of the removal rate of ion and consumption per ton water increases. When the ionconcentration of out-let meets requirements, To increase influent flow can reduce the energyconsumption per ton water.(4) The Langmuir adsorption isotherm the model and Freundich adsorption isothermmodel fitted double-layer adsorption of ions. The results are as follows: Langmuir adsorptionisotherm model and the Freundlich isotherm model can accurately describe the adsorptionmechanism of the double-layer. When the voltage increases, adsorption capacity qe and the maximum adsorption qmwould increases.1/n value ranges from0.1to0.6at differentvoltages, it shows that the double-layer have a higher rate of adsorption of the ion in thevoltage range.(5) The Lagergren kinetic model and Lagergren quasi-second order kinetic model fitteddouble-layer adsorption of ions. The results are as follows: The Lagergren kinetic model andthe Lagergren quasi-second order kinetic model can accurately describe the reaction kineticsmechanism of the double-layer. It not only improve ion adsorption rate(k2) of voltage but alsoincrease its adsorption capacity(qe).(6) Kannan particle diffusion model and Liquid film diffusion model fitted process whichions migrate to the electric double layer in electrosorption. The results are as follows: The ionis controlled by the liquid film diffusion and pore diffusion in the process of double-layeradsorption of ions.(7) The results shows that electrosorption technology using for advanced treatment ofsecondary treatment of sewage water achieves good effects with an average salinity removalrate of75%and an average water production rate of85%. The consumption per ton water is1.9kWh/m3. Therefore electrosorption desalination technology has widespread applicationvalue.(8)Using adsorption isotherm model, Kinetic model and Ion diffusion model analysiseffect of desalinization of the double-layer in order to improve the desalting performance ofthe electrosorption technology.