In this study, a novel adsorptive membrane was prepared from chitosan as the functional polymer and some additive blend solutions by solution casting method. The modified chitosan membrane was characterized by FTIR and its Water Swelling Ratio (WSR). The adsorption of copper ions on the adsorptive membrane was investigated in batch experiments. The results obtained from the experiments indicated that the membrane had a good adsorption capacity for copper ions, the optimal ionic strength and pH were 0.1 and 5–6, respectively. Compared with the Langmuir isotherm model, the experimental data were found to be following the Freundlich model.

Lithium is one of the most important light metals, which is widely used as raw materials for large-capacity rechargeable batteries, light aircraft alloys and nuclear fusion fuel. Seawater, which contains 250 billion tons of lithium in total, has thus recently been noticed as a possible resource of lithium. While, since the average concentration of lithium in seawater is quite low (0.17 mg·L−1), enriching it to an adequate high density becomes the primary step for industrial applications. The adsorption method is the most prospective technology for increasing the concentration of lithium in liquid. Among the adsorbents for lithium, the ion-sieve is a kind of special absorbent which has high selectivity for Li+, especially the spinel manganese oxides (SMO), which among the series of ion-sieves, has become the most promising adsorption material for lithium. In this study, the SMO ion-sieve was prepared by a coprecipitation method. The preparation conditions were discussed and the sample characters were analyzed. Recovery of Li+ from seawater were studied in batch experiments using prepared ion-sieve, and the effect of solution pH and the uptake rates were also investigated in different Li+ solutions.

The Li+ uptake was studied by two lithium ion-sieves with different properties (surface, crystal configuration, and grain size). The reaction of Li+ uptake was investigated in batch experiments via the pH technique. Equilibrium studies were performed in solution pH 7, 10, 12 and the Langmuir equation was applied to the data. The results indicated that there was strong responsive behavior of Li+ uptake to pH in neutral or weak alkaline solutions, and Li+ uptake could not proceed completely for reason of pH descent with proton releasing from ion-sieves. Sieve-2 had faster Li+ uptake rate than Sieve-1 owing to the quicker intraparticle diffusion in the small grain. The Li+–H+ ion-exchange was accepted as the main mechanism of Li+ uptake by spinel-type manganese oxide with manganese valence nearly equals to +4. Furthermore, it suggested that Li+ uptake by ion-sieves would be necessary to study in buffer solution.

In this study, Li+ uptake by ion sieves was studied in a fixed-pH aqueous phase using a pH 8.0 buffer solution of ammonia/ammonium chloride. Two different spinel-type manganese oxide ion sieves were used to investigate the effect of intrinsic properties of ion sieves on Li+ uptake. The effect of ionic strength was also considered for potential recovery of lithium from seawater and brine. The results of Li+ uptake indicated that the sorption isotherms fit the Langmuir model well. The uptake was found to obey a pseudo-second-order rate. The thermodynamic parameters, ΔG0ΔG0, ΔH0ΔH0, and ΔS0ΔS0, were calculated, and the results indicated that the Li+ uptake by both ion sieves was endothermic. The influence of ionic strength was mainly found on the kinetics of Li+ uptake. Moreover, the global reaction rate is probably controlled by both intraparticle diffusion and boundary layer diffusion, and the extent of control is greater for intraparticle diffusion than for boundary layer diffusion for Sieve-1; the reverse is for Sieve-2. Finally, Sieve-2, with high H content and small grain size, was proposed as a more suitable absorbent for recovery of lithium from seawater or brine.The Li+ uptake by two different lithium ion sieves was studied in pH 8.0 buffer solutions. Equilibrium were reached within 24 h.

The application of reverse osmosis (RO) for desalination process has increased rapidly with the construction of large RO plants. Although there have been considerable improvements in membrane materials and operation experience, the fouling of membranes is a significant problem up to the present. There have been many instances of fouling of RO membranes caused by the presence of iron and silica. Biomineralization is usually believed to be caused by microorganisms metabolizing at iron and silica present. Its formation process was studied and described first in the present work, then the enhanced coagulation with Fe(VI) and UF membrane treatment process for pretreatment of reverse osmosis for desalination has been investigated in a laboratory for 3–4 months. The main aim is to reduce the feed water pollution, such as turbidity, iron, silica and aglae, microbial contamination in order to control biofouling and mineralization on the membrane surface. The results showed that the biomineralization formation process is the adsorption of organism and the biosorption of inorganics onto the organic matrix. The pretreatment results show that turbidity is less than 0.5 NTU, iron concentration never exceeds 0.2 mg/l, silicon concentration must not exceed 0.1 mg/l; and the removal rate of aglae and microbial is more than 98%.

As a biomass material, cotton was investigated for feasibility to be used as a cost-effective biosorbent for boron removal as the post-treatment in a desalination plant. Based on the batch tests, cotton demonstrated a good capacity of adsorption at a pH about 7. This capacity was found to increase with an increase of boron concentration; the maximum capacity is 11.3 mg/g. The linear Freundlich isotherm was rather the linear Langmuir isotherm. The semiempirical of mono-parameter modeling with pH relation was developed in this study and experimental results and predicted data by the model are consistent.

•The CNTs composite electrodes were fabricated by using EPD method for the first time.•The CNTs composite electrodes could remove Ca2 + by CDI progress.•The CNTs composite electrodes have excellent selectivity for Ca2 + than Mg2 + and Na+.Electrophoretic deposition (EPD) method was used to fabricate Carbon nanotubes (CNTs) and Ca-Selective zeolite composite electrode. The prepared electrode was employed in electrosorption of calcium ions in capacitive deionization. The morphology, porous size distribution, pore volume and electrochemical properties were characterized by scanning electron microscopy, N2 adsorption at 77 K and Cyclic Voltammetry (CV), respectively. The results obtained from experiments showed that the optimum proportion between CNTs and zeolite was 1:4. It was also found that the optimum applied electrosorption voltage was 2.0 V and the maximum equilibrium electrosorption capacity was 25 mg/g with initial Ca2 + concentration of 750 mg/L. The electrosorption process could be validated by both of pseudo first and second order kinetic models. Furthermore, the selective ion electrosorption experiments were repeated in solution with different ions, and it was observed that the electrosorption capacities of cations on the CNTs composite electrode followed the order of Ca2 + > Mg2 + > Na+. Finally, the prepared electrode can be reused in long-term electrosorption process.