| With the economic growth, it’s more and more hard to balance the stability of the eco environment. In the sence of the water environment, what we should do is to save and recycle the water and develop the policy. In recent years, membrane methods such like the electro dialysis, ion exchange technique and reverse osmosis and biological methods had been widely promoted. But the waste water could be produced in these water methods, and what must to be a burden for the long-term accumulation. Capacitive deionization has the advantages of high desalination rate, environment friendly and non secondary pollution, and researchers had done something. However, in the study of that how to promote the capacitive deionization materials’ researchers adsorbability, researchers learned a little.The study is based on the capacitive deionization and set ACF as the basic material, modified by diverse ways, in order to improve the removal effect of NaCl water and RO concentrate, and which could be a reference for the capacitive deionization and relevant study. Besides, made IR characterization for ACF so that observed the changes and combined the removal effect and process to explain the influences of modifying to ACF.At the same time, used the mathematical thinking to make the kinetic fittings of the RO concentrate salinity and ammonia nitrogen. As well as differentiate the adsorption curves of conductivity of RO concentrate salinity, then discussed the changes of effect of different modified materials mass transfer of capacitive deionization. Furhter more, summarize the researchers’ achievement of their instrument experimental facility and the relevant knowledge, designed the integrate capacitive deionization units.The mainly work and the results were showed as followed:(1)Designed the capacitive deionization equipment, improved the water pass by water distribution channel, compared and selected the partition then used spongia for ensuring a elastic fullness and perturbation, so that improved the mass transfer rate as far as possible. To do the single factor experiments in capacitive adsorption equipment of flow, inlet concentration and voltage, to observe the influences of different factors; then experiment fixed water concentration and designed the three factors(which were flow, voltage and plate distance) three levels experiment, to confirm the ideal operating conditions.Using the SPSS to do the analysis of range and variance, found the order of the influence of different factors to the conductivity average removal rate were plate distance, voltage and flow. Then finally determine the conditions were plate distance 2mm, voltage 2.1v, flow 20ml/min, and compared and selected the regenerative way of combing the short circuit and inversely connect.(2)Modified the ACF by NaOH, KOH and ammonium hydroxide, marked to ACF-NaOH、ACF-KOH and ACF-NH3, then used for treating the NaCl water and RO concentrate. Resulted that ACF-NH3 had the best removal rate to the conductivity of NaCl water and RO concentrate, ammonia nitrogen, CDOCr, the average rate were 19.92%,9.69%,41.80% and 43.97% in order. In addition, ACF-NaOH and ACF-KOH had a approximated removal rate for other indexes, alkali metal hydroxide had the resemble mechanism for modifying ACF surface pore and functional group. Using differential method to RO concentrate conductivity and plot derivate curve, ACF-NH3 shows the best absorption and regeneration.(3)Modified the ACF by NaOH, KOH and ammonium hydroxide, marked to ACF-H2SO4,ACF-HNO3 and ACF-H3PO4, then used for treating the NaCl water and RO concentrate. ACF modified by HNO3 and H2SO4 had a higher removal rate, the oxidbillity improved ACF perssad and pore size distribution and so on, the result of infrared spectroscopic analysis had proved this too. ACF-HNO3 had the best effect for the conductivity of NaCl water and RO concentrate, CODCr and turbidity, orderdly the average removal rate were 21.10%,9.83%,53.21% and 88.59%. At the same time, ACF-H2SO4 and ACF-H3PO4 had a good removal effection, the average removal rate were 57.80%,78.16%.(4)Modified the ACF by metals of FeCl3,AgNO3 and CuCl2, then marked as ACF-FeCl3,ACF-AgNO3 and ACF-CuCl2, and had the test of capacitive deionization for NaCl water and RO concentrate. Capacitive deionization of ACF modified by metal had changed the functional group, and applied the active site for absorbtion so that showed a selected effect. ACF-AgNO3 had the best effect for NaCl water and RO concentrate, the average removal rate were 20.69%,8.44% in order. And in other indexes, ACF-CuCl2 showed the best average removal rate 61.49% to ammonia nitrogen, but ACF-FeCl3 had the highest average removal rate69.51%。(5)Compared modified methods of NH3,HNO3 and AgNO3, studied electrode material remove process and rate to NaCl water and indexes of RO concentrate, found materials modified had the resemble absorption process, ACF-HNO3 showed the best effect. And for the RO concentrate, CODCr and UV254 had a positive correlation, ammonia nitrogen and turbidity were another group. And these indexes were relatived and competitive.(6)Combined the HNO3 and AgNO3 to modify the ACF, then marked ACF-composite, and had the treatment of capacitive deionization to NaCl water and RO concentrate, and observed the absorption of different indexes. ACF-composite’s average removal rate to NaCl water was 23.94% which was higher than ACF-HNO321.10%. But it had a great improvement in the overall performance, conductivity, ammonia nitrogen and CODCr had a better removal rate, each average removal rate were 23.94%,55.01% and 55.37%. Moreover, ammonia nitrogen, CODCr, UV254 and turbidity still had some competitive absorption probably, as well as CODCr and UV254 showed positive correlation in the overall tend.(7)Made the first and second order kinetic, Elovich and Gauss function fitting for the capacitive deionization to RO concentrate salinity and ammonia nitrogen, showed that Gauss function’s fitting results had a higher R2 for the reaction process RO concentrate salinity and ammonia nitrogen, which the average R2 were above 0.90. The first order kinetic had a better fitting effect than second order kinetic and Elovich, the fitting parameters performed the same tend to the process.(8)Used the mathematical method of differential, then derivated curves for capacitive deionization absorbed RO concentrate of different materials in the first absorption and regeneration period, the curve derivated marked rate of conductivity. Resulted that ACF modified had a higher removal rate for RO concentrate and regeneration had also improved in a way, changed the absorption and regeneration efficiency. ACF-composite, ACF-HNO3,ACF-AgNO3 delayed the time in the most removal period, and regeneration also showed well. This certified ACF modified had been improved in the absorption and regeneration property for another face, so that a higher removal ration performed.(9) IR characterization for ACF pre or modified, found that ammonium hydroxide existed a amidogen absorption peak, ACF modified by HNO3 showed more evident in the absorption peak of oxygen-containing functional group, and ACF-AgNO3 mainly manifested for the influence of the waving shape. For the ACF-composite, the absorption peak in oxygen-containing functional group area showed more obvious, and there were a clear absorption peak nearly 500 cm-1, which would probably had the relationship with the silver ions brought in. |
PDF Full Text Request