Computational fluid dynamics simulation was carried out for three-dimensional desalination modules

Herein, we report the galvanostatic modification of a commercial cation exchange membrane CMX by polypyrrole (Ppy). The presence of Ppy in the cation exchange membrane (CEM) was confirmed by cyclic voltammetry, stereo microscopy, fourier transform infrared spectroscopy, scanning electron microscopy, and energy dispersive X-ray. Ppy was present both on the membrane surface and inside the pores. The quantity of Ppy in CEM, compactness of Ppy, and the charges on Ppy (negative or positive) were controlled effectively by changing the electrosynthesis conditions. The permeability and water content of the modified membranes obtained under different conditions were investigated. The transport properties of the modified CEMs were evaluated qualitatively using polarization curves and quantitatively by chronopotentiometry. NaCl and MgCl2 solutions ranging in concentrations from 5 mM to 0.1 M were used for testing the selectivity. The presence of Ppy in the membranes decreased the transport number of Na and Mg, and the reduction in transport number was more significant for Mg.

Solar still is not so much attractive in a market due to its lower productivity. Researchers from all around the world have tried to improve distillate output of solar still, but still, no one has tried solar still to put as a commercial product. Hence, there is a lot of scope of research work on the solar still. In this present review paper, various research works done by researchers have shown, and three primary methods like use of fin, energy storage materials and multi-basin solar still have discussed. All of above methods are crucial for improvement in distillate output of solar still. Fin enhances the surface area of water inside the basin for even distribution of water for increment in distillate production. Energy storage materials have pore holes to store the hot water and excess energy during sunshine hours and release during off-sunshine hours for the increase in distillate production. Multi-basin solar still uses the latent heat of condensation from lower basin to increase a temperature of the top or middle basin for increment in distillate production. Hence combination all of above method in the solar still, then the solar still can be used as a commercial product for potable water in household and industry.

filtered through a desalination membrane in dead-end cells under agitation. Three types of tests were

This work presents a modified solar still with pin fins absorber and external condenser. An experimental comparative study is carried out between the modified solar still with pin fins absorber and condenser, still with pin fins absorber and conventional still. This experimental study is conducted to evaluate the thermal behavior (evolutions of absorber and glass temperatures) and the water production performance of the modified solar still with pin fins absorber and condenser compared to other designs. All experiments are carried out under the meteorological conditions of the region of Gafsa-Tunisia during the days 01/26/2016, 01/27/2016 and 01/29/2016. Experimental results are presented, quantified and discussed to show the utility of the proposed modified solar still.

A rotary energy recovery device (RERD), as the energy saving equipment of seawater desalination

Electrodialysis (ED) combined with bipolar membrane, a new system known as bipolar membrane electrodialysis (BMED) has been developed to separate ions from aqueous saline solutions and recover them in their corresponding acids and bases. In this study, separation and recovery of lithium and boron from aqueous solution by BMED method was investigated. Lithium and boron were recovered as LiOH and H3BO3 with BMED, respectively. The influence of process conditions such as applied potential, initial sample volume and pH on BMED performance was monitored. The performance of BMED method increased with an increase in applied voltage but decreased with an increase in initial sample volume. At optimum conditions of 15 V and 0.5 L as initial sample volume, separation and recovery of lithium were 99.6% and 88.3%, respectively, while the respective values for boron were 72.3% and 70.8%. An increase in pH improved separation and recovery of boron more than those of lithium. At pH 12.25, separation and recovery of boron were 95.6% and 78.8%, respectively. The BMED method was found to be effective for simultaneous separation and recovery of lithium and boron from same aqueous solution at optimum operating conditions.

Environmental and economic impacts of the fertilizer drawn forward osmosis (FDFO) and nanofiltration (NF) hybrid system were conducted and compared with conventional reverse osmosis (RO) hybrid scenarios using microfiltration (MF) or ultrafiltration (UF) as a pre-treatment process. The results showed that the FDFO-NF hybrid system using thin film composite forward osmosis (TFC) FO membrane has less environmental impact than conventional RO hybrid systems due to lower consumption of energy and cleaning chemicals. The energy requirement for the treatment of mine impaired water by the FDFO-NF hybrid system was 1.08 kWh/m3, which is 13.6% less energy than an MF-RO and 21% less than UF-RO under similar initial feed solution. In a closed-loop system, the FDFO-NF hybrid system using a TFC FO membrane with an optimum NF recovery rate of 84% had the lowest unit operating expenditure of AUD $0.41/m3. Besides, given the current relatively high price and low flux performance of the cellulose triacetate and TFC FO membranes, the FDFO-NF hybrid system still holds opportunities to reduce operating expenditure further. Optimizing NF recovery rates and improving the water flux of the membrane would decrease the unit OPEX costs, although the TFC FO membrane would be less sensitive to this effect.

Modern bio-refineries generate considerable volumes of wastewater that are highly coloured (5600–572,000 PtCo) as well as being concentrated in both salts (conductivities up 72.4 mS cm− 1) and organics (up to 380 g COD L− 1). In this study, bench-scale batch electrodialysis was performed to examine the feasibility of separating salts from organics for a range of industrial biorefinery streams. High levels of salt removal (up to 96% for a lignocellulosic effluent) were possible with minimal organic losses (0.3–6.3%), while key performance parameters were highly encouraging (current efficiencies = 69–104%; specific power consumption = 0.44–1.59 kWh kg− 1 of salt recovered). Collectively, the experimental results obtained here showed the cost-effective potential of electrodialysis to separate salts from organics in complex bio-refinery streams at the industrial scale.

Seawater reverse osmosis (SWRO) develops rapidly and benefits from excellent performance of isobaric energy recovery devices (ERDs). Leakage characteristics directly affect the ERD performance. In this paper, leakage characteristics of a fully-rotary valve energy recovery device (FRV-ERD) which is a new type of isobaric ERD are studied numerically. Leakage variation of the fully-rotary valve (FRV) that is the key part of the device caused by pressure difference and geometric parameters is investigated. Then performance of the FRV-ERD is discussed. Results indicate that leakage rates of forward and reverse leakage within the same FRV are almost equal to each other and present a good linear relationship with pressure difference. Leakage rate is exactly proportional to the 3.0 power of the clearance height. Effects caused by changing the length and diameter are equivalent. The leakage rate decreases sharply first and then slowly after the length or diameter is larger than a specific value of which the axial length and the half circumference are equal to each other. The performance of the larger size FRV-ERD is much better than the smaller one, and the required clearance is also significantly increased, alleviating machining difficulty to some extent.