The climate change creates a most concerned social problem all over the world. It can accelerate both the atmospheric circulation and the hydrological cycle, and will lead to a series of water security problems. In this paper, the impact of the climate change on the water security is reviewed from five aspects, including the water environment, the water ecology, the water engineering and the water supply security, and the coping strategies are suggested.

The membrane separation technology developed rapidly in the 1960s, as a new separation technology. The conductive materials are not only used in the special separation, but also in the traditional separation. Since the discovery of conducting polymers, the use of conductive materials in the preparation of the separation membrane began to develop quickly. The conductive polymer composite membrane not only has the characteristics of conductive polymers, but also has the flexibility and processability of the insulating polymer membranes. This paper reviews the use of conductive materials in the preparation of the separation membrane, the improvement and the applications of the separation membrane prepared by conductive materials.

The liquid radioactive waste treatment is a challenging task in the rapid development and extensive applications of nuclear technology. The membrane technologies have a potential application in the liquid radioactive waste treatment. In this paper, the mechanisms of different membrane processes to treat the liquid radioactive waste, including the microfiltration, the ultrafiltration, the nanofiltration, the reverseosmosis, the electrodialysis, the membrane distillation, and the liquid membrane process, are reviewed. The application and the research progress of the membrane treatment of the liquid radioactive waste water at home and abroad are discussed in detail, and the new directions and the existing problems of the membrane technology in the field are pointed out.

The microbial fuel cell (MFC) is a promising bio-electrochemical system, which can directly convert the organic chemical energy into the electrical energy with microbes as the catalyst to degrade the organic sewage and produce electricity at the same time. This paper presents a comprehensive review of the latest studies of electrode materials, including the modification and the functionalization of anode materials, and of the cathode catalyst. Additionally, the direction of the electrode design and research in the MFC is suggested.

The graphene oxide(GO) is a one-atom thick nanosheet with good hydrophilic properties and the water molecules move fast between GO layers. Adjusting the distance between GO membranes can achieve a good retention of the solute, with excellent separation performance in the water treatment. This paper reviews the preparation methods of GO-basedmembranes, including the vacuum filtration, the spray coating, the spin coating, the dip coating and the layer by layer self-assembly method. In addition, the research progress of GO-based membranes in reverse osmosis, nanofiltration and pervaporation is discussed in detail. The future applications of GO-based membranes in water treatment are discussed as well.

The reverse osmosis membrane technology plays an important role in the supply of pure water. The high water production is always desirable. In this study, a new acid acceptor consisting of the crown ether (18-crown-6)/KOH is used to catalyze the interfacial polymerization reaction for the polyamide reverse osmosis membrane fabrication to increase the membrane flux. The 18- crown-6 and the KOH will form a complex compound, to help the diffusion of the KOH from the aqueous phase to the organic phase, so that the KOH can work more efficiently to catalyze the polymerization. Meanwhile, the 18-crown-6 can effectively inhibit the excess hydrolysis of the TMC from the KOH, preventing a significant deterioration in the ion rejection of the membrane. To verify the above reasoning, the SEM and XPS characterizations are used to show that the membrane has a thin and properly hydrolyzed surface morphology. The membrane performance test shows that the application of the (18-crown-6)/KOH as the acid acceptor can promote the membrane flux better (up to 72% increase) as compared with using only the KOH (38% increase). Moreover, the use of the (18- crown-6)/KOH can help the membrane to maintain a reasonable NaCl rejection of above 90%. That solves the problem of rejection deterioration when only the KOH is used as the acid acceptor with a rejection of below 60%. Although Cs⁺ has a smaller hydraulic radius than that of Na⁺, this kind of membrane also enjoys a similarly excellent separation behavior with respect to CsNO3. That means that the (18-crown-6)/KOH catalyst composition is effective and applicable in future.

The emergency water-bag is a gadget for supplying drinking water under emergent situations. The preparation and the performance of the cellulose triacetate (CTA) forward osmosis (FO) membrane and the research progress of the emergency water-bag made of the CTA membrane are studied in this paper. The water flux and the rejection performance of the heavy metal ions of the emergency water-bag are tested in the homemade water. With this CTA membrane, a FO water flux of 8.77 L/(m²·h) and J_s/J_w of 0.56 g/L are obtained under a standard test condition using 0.5 mol/L NaCl as the draw solution and the deionized water as the feed. The water-bag containing the glucose solution can draw 180 g water in the water-bag from the surface water sample and this water processing capacity can meet the water demand to sustain life. The rejection rate of the heavy metal with the hydrated ion radius larger than 100 pm can reach 95%, and the concentration of Pb(II), Cr(III), and Hg(II) in the water-bag is found to be lower than the National drinking water standard (GB5749—2006). The As(III) concentration in the produced water is higher than the standard, because the radius of the hydrated As(III) is less than 65 pm. Further improvement in the FO membrane dense layer is required to remove micro-particles at a high rate.

A new type of ultrafitration membrane with small molecular weight cut-off (MWCO), with PSF, with DMAC, with polyvinyl pyrrolidone (PVP) and FeCl2 as its raw materials, is prepared by means of the phase inversion method. The morphology of the membrane is controlled by adjusting the temperature of the casting solution, the temperatures of the coagulation bath and the support layer of membrane. The prepared ultrafitration membrane intercepts the matter of molecular weight: 2000-10000 with the interception rate of PEG of over 90% under the controlled process condition.

The membrane separation is a promising way for the treatment and reuse of oily wastewater. The membrane material plays a key role in the oil/water membrane separation and its surface/interfacial morphologies and physiochemical characteristics are responsible for the separation efficiency and the lifespan of the membrane. This paper reviews the recent advances in the design and the modulation of oil/water separation membrane surfaces and interfaces. The effects of the membrane surface chemistry and morphology on the membrane separation performances are summarized. The scientific fundamentals of the surface/interfacial design, the construction of the hydrophobic surface and the hydrophilic inversion, the preparation of the superhydrophilic surface and the stimuli- responsive membrane are discussed in detail. Some unsolved problems in oil/water separation materials and membrane techniques e.g. the development of the antifouling and chemically stable membrane materials, the thermally tolerant membranes, and the demulsification technique are addressed. Finally, the directions of further studies are proposed.

With the rapid development of massive industrial productions, the emission amount of the industrial wastewater is increasing sharply, most of which contains sulfate. The excessive emission of sulfate will cause serious pollution and damage to the environment water body. To solve this problem, in this paper, the sodium sulfate waste is used as the raw material, a new technology of the bipolar membrane electrodialysis is adopted, thus, the wastewater containing sulfate is reasonably reutilized and converted efficiently into the corresponding acid and alkaline. In the experiment, the effects of the current density, the feed concentration and the initial pH concentration on the membrane reactor are investigated, and the performances of the two ion-exchange membranes are compared. It is shown that in the experimental range the yield of the sodium hydroxide reaches 84.08%, the average current efficiency of the process reaches 54%, the energy consumption reaches 5.29 kW·h/kg, and the sodium hydroxide yield and the process energy consumption rise with the increase of the current density. When the current density is constant, a higher raw material concentration can make the membrane reactor stay at a relatively lower level during the experiment, which reduces the energy consumption. The right amount of the initial acid and alkali can reduce the energy consumption, but the current efficiency will decrease.

The wastewater reuse is an important way out facing the water resource and energy crisis, and the coupled process of the advanced wastewater treatment and the microalgal energy production is an important issue in this respect. In this paper, the activated sludge as the fixing bacteria is immobilized with Chlorella vulgaris and Scenedesmus obliquus, respectively, for the enhanced municipal wastewater treatment. The microalgal growth, the nitrogen and phosphorus removal and the oil production of the coimmobilized microalgae and bacteria, the immobilized microalgae, and the suspended microalgae are then compared. It is shown that the co-immobilized bacteria and algae are better than the immobilized bacteria and the immobilized algae in their effect on the nitrogen and phosphorus removal, and better than the non immobilized algae and bacteria as well, while the co-immobilized bacteria and algae produce much more lipid. When the concentrations of the NH₄⁺ - N and PO₄^3--P in the municipal wastewater are about 25 mg/ L and 3 mg/L, the NH₄⁺ -N and PO₄^3- -P in the wastewater are removed completely by the co-immobilized Secenedesmus obliquus and bacteria, whereas the lipid yield of C. vulgaris reaches 16.5%.

In this work, ultrafiltration- nanofiltration integration membrane technique was applied in alkali reduction wastewater treatment. The results indicated that chemical oxygen demand (COD) of alkali weight reduction wastewater was effectively decreased by this process, and COD removal rate reached over 80%. Meanwhile, the effect of reused wastewater on the polyester reduction process was also analyzed, with main factors, such as temperature, time, alkalinity, and ethylene glycol content (accumulated) discussed in detail. The polyester reduction rate increased with the increase of temperature, process time and alkali concentration. The accumulating ethylene glycol content could also promote the reduction effect of the polyester. The recovery and comprehensive utilization of terephthalic acid, water, alkali and ethylene glycol could be realized by this technique.

For improving the hydrophily and the anti-fouling performance of the polyvinylidene fluoride (PVDF) membrane, the PVDF/polymethyl methacryla (PMMA)/polyether sulfone (PES) blend membrane is prepared by the immersing precipitation. It is shown that the ternary system has a good compatibility when the ratio of PVDF/PMMA/PES is 85:10:5, 80:15:5, 75:15:10 and 70:20:10. Additionally, the hydrophilicity of those membranes is improved. The optimized PVDF/PMMA/PES blending ratio is 70:20:10. Under this condition, the water flux is 43 L·m^-2·h^-1, the porosity is 73%, the advancing contact angle is 75.88°, and the receding contact angle is 20.22°.

The rapid growth of the Enteromorpha prolifera (EP) in beaches of some coastal city has caused serious environmental problems. The proper disposal of large quantity of waste EP is an important issue. In this paper, the biomass of the EP is thermally pyrolyzed into a biochar and its sorption characteristics with respect to the naphthalene in water are studied. It is shown that the sorption of the naphthalene by the EP biomass and the lower temperature (150℃) derived EP biochar is governed by a weak partition process, while the biochar derived from the EP at the higher temperatures of 250 and 350℃ exhibits much better sorption capacity than the others, and their sorption is contributed by both the adsorption and the partition. However, the EP biochar derived at 500℃ has a weaker sorption capacity than at 250 and 350℃, and the EP biochar derived at 700℃ has almost no carbon content except for some minerals, and exhibits almost no sorption capacity with respect to the naphthalene.

The PANI film anodes are prepared by the potentiostatic method, the pulse polarization and the cyclic voltammetry (CV), and are applied in a fixed bed microbial fuel cell to investigate the performances of the electricity generation and the wastewater treatment, respectively. It is shown that the PANI film anode modified by the CV enjoys the best conductivity, as compared with those obtained by the potentiostatic method and the pulse polarization, and the electrode resistance is greatly decreased from 55.45 Ω of that prepared by the potentiostatic method to 3.65 Ω. The PANI film anode prepared by the CV is applied in the MFC, the maximum power density and the open circuit voltage reach 215.6 mW·m^-2 and 849.3 mV, respectively, 50.6% and 45.1% higher than those of the PANI film anode modified by the potentiostatic method. Compared with the potentiostatic method and the pulse polarization, with the CV being used to modify the PANI film anode, the MFC startup time can be shortened, the electrical stability increased and the sewage removal rate improved. It is a new way to prepare the high performance anode for the MFC.

In order to obtain high water flux and salt rejection polyelectrolyte complex nanofiltration membranes (PECNFMs), a novel type of PECNFMs is prepared with the polyethyleneimine (PEI), the sodium alginate (SA) and the carboxymethyl cellulose (CMC) via the in-situ ionic cross-linking method. The chemical compositions, structures, and hydrophilicity of the PECNFMs are characterized by the Fourier transform infrared spectroscopy (FTIR), the field emission scanning electron microscope (FESEM), and the water contact angle (CA), respectively. The effects of the PEI mass ratios, the polyanionic types, the feed inorganic salts, and the operating temperature on the nanofiltration performance of the PECNFMs are investigated. It is shown that the in-situ ionic cross-linking PEI/ SA PECNFMs enjoy a higher water flux as compared to the PEI/CMCs with the some PEI mass ratio, and the surface charge of the PECNFMs could be turned from negative to positive by increasing the PEI mass ratio. With the optimized PEI/SA value of 0.9, a water flux of 13.4 L·m-2·h-1 is obtained with the MgCl2 rejection being maintained at around 94.0% (with 1 g·L-1 aqueous MgCl2 solution at 25℃ and 0.6 MPa). Moreover, with the PEI/SA value of 0.9, the best Na+/Mg2+ selectivity (αMg2+Na+=10.4) is secured. This study provides an approach for fabricating PECNFMs with high water flux and salt rejection via an in-situ ionic cross-linking method and opens new avenues for fabricating high performance nanofiltration membranes.

The proper disposal of massive agricultural solid waste is one of main agricultural and environmental concerns. The bagasse and the corn cob are selected as two typical agricultural solid wastes in this study to investigate the adsorption kinetics and the equilibrium isotherms of the dye methylene blue (MB). It is shown that the adsorption rate is great and the equilibrium is reached in less than 4 h. The sorption kinetics can be well described by a pseudo-second-order kinetic model and is fitted with the R2 value greater than 0.9, indicating a chemisorption dominated process. The adsorption isotherms are non-linear, and can be well fitted by the Langmuir adsorption model. The bagasse and the corn cob show a good sorption capacity with respect to the MB, and the maximum adsorption amount of the MB by the bagasse and the corn cob are 22.03 and 19.72 mg/g, respectively.

The S2 inverse problem is very important in a design process. With the use of a reasonable and verified loss model, an evaluation method is developed for the civil high bypass ratio fan, and the effect of key geometric parameters on the efficiency of the turbofan is investigated. It is shown that, when the radius of the inlet casing is increased to a certain extent, the further increase of the radius does not obviously improve the turbofan efficiency. When the hub ratio is greater than 0.295, the fan efficiency will fall sharply. The constant case diameter design is effective in the improvement of the turbofan efficiency. In the determination of the outlet size, not only the requirement of the flow coefficient, but also the matching with the downstream part have to be taken into account to improve the efficiency of the whole compression system.