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Arsenic is one of the major pollutants in water resources which are highly toxic to consumers. Recently, a new class of adsorbents has been used to remove environmental pollutants such as Zeolite iImidazole Frameworks (ZIF-8). The aim of this study was to synthesise ZIF-8 and optimise for arsenic adsorption. The prepared ZIF-8 was characterised by FTIR, XRD, EDX, FE-SEM, and BET surface area. The ZIF-8 performance was assessed for variables such as initial arsenic concentration, pH, adsorbent dosage, and contact time. To measure the residual arsenic concentration, ICP-OES was used. Morphology of the synthesised ZIF-8 was dodecahedral. The particle size of synthesised ZIF-8 was in the range of 420 nm to 744 nm. The surface area of dodecahedral-ZIF-8 was 1566 m2 g−1. The study findings showed that experimental data could be well represented by the pseudo-second-order model and the Langmuir isotherm model. The arsenic adsorption on ZIF-8 was endothermic. The results of this study showed that ZIFs can be used to remove environmental pollutants effectively. [ABSTRACT FROM AUTHOR]

Dyes are one of the most important environmental pollutants that have a significant impact on the environment, especially water resources. Dyes are toxic compounds that have severe effects on the environment. Methylene blue dye (MBD) causes problems like nausea, profuse sweating, vomiting, mental confusion, and methemoglobinemia. In this study, ZIF-8 with leaf-shaped morphology was used for MBD adsorption. All experiments were performed in batch conditions. The Leaf-shaped ZIF-8 is obtained at the molar ratio of 2-methylimidazole/Zn = 8. The prepared leaf-shaped ZIF-8 was white powder. The as-synthesis adsorbent is in the form of the leaves of a tree. The thickness of Leaf-shaped ZIF-8 is about 6–98 nm. Alkaline conditions were much more favourable than acidic to MBD adsorption. By increasing the dosage of Leaf-shaped ZIF-8, MBD adsorption increased until reaching an equilibrium dose at 0.5 g/L. the kinetic model of pseudo-first-order and the isotherm model of Langmuir have the highest coefficient of determination (R-square). Based on the Langmuir model, the maximum capacity of MBD adsorption on the Leaf-shaped ZIF-8 was 205 mg/g. In this study, the RL was less than one which indicates MBD adsorption is favourable. Also, based on the Freundlich model, 1/n was 0.26, favourable adsorption condition was favourable. [ABSTRACT FROM AUTHOR]

The performance of a newly commercialized aquaporin (AQP)‐based biomimetic forward osmosis (FO) membrane was evaluated with several commonly used fertilizers ((CO (NH2)2, KCl, CaCl2, (NH4)2SO4 and (NH4)2HPO4) as a draw solutions (DSs) to verifying the possible implementation of this AQP‐FO membrane in the fertigation industry. Also, DS and feed solution (FS) concentrations were evaluated under FO and pressure retarded osmosis (PRO) operation modes. The results showed that CaCl2 seems to be a more suitable DS in terms of the tradeoff between water flux and salt permeability, compared to the other DSs used in this study. However, KCl gained the highest performance in terms of water flux which was 13.9 and 24.1 Lm−2 h−1 in the FO and PRO mode, respectively. The performance of the AQP membrane in terms of water flux and reverse solute flux can be improved by modifying the structural and the membrane inhibitor layer characteristics for utilizing in commercial scales to compete with other available membranes of the FO process. [ABSTRACT FROM AUTHOR]

BACKGROUND Novel nanocomposite membranes with spatial distribution of nanoparticles (NPs) were fabricated for forward osmosis (FO) applications. In this work, TiO2 and Al2O3 NPs were used as hydrophilic additives in order to improve the performance and fouling resistance of cellulose acetate (CA) FO membrane. RESULTS: Attenuated Total Reflection Fourier Transform Infrared (ATR‐FTIR) and x‐ray diffraction (XRD) analyses confirmed the successful incorporation of the NPs into the synthesized membranes. The specific reverse salt flux (SRSF) of the TiO2 modified membrane was reduced from 0.88 to 0.56 g L−1, which was attributed to enhanced hydrophilicity, porosity, and the simultaneously improved water and salt permeability coefficients. After the evaluation of CA membranes with various contents of TiO2 NPs, Al2O3 NPs were added to the membrane structure as a secondary additive under the optimized content of TiO2 NPs. Al2O3 NPs have a higher dispersion in the membrane sublayer beneath, which can affect the hydrophilicity and surface charge of the membranes. Al2O3 and TiO2 modified membranes showed the lowest values of contact angle and zeta potential in neutral pH, which was 56.7°and − 68.4 mV, respectively. This membrane showed a water flux (WF) of 15 L m−2h−1 and an SRSF of 0.36 g L−1 when using 1 mol L−1 NaCl as a draw solution. The fouling behavior of sodium alginate on the neat and modified membranes was also investigated, and the results showed a reduced fouling propensity and a superior fouling reversibility in the modified membranes. CONCLUSION: Based upon these findings, using low‐density hydrophilic NPs in the membrane structure can fabricate membranes with more hydrophilicity, excellent FO performance, and high organic fouling resistance. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Due to the lack of affordable and feasible wastewater treatment technologies, various industries in developing countries are discharging chromium (Cr) without meeting the environmental standards. Here, the aim was to employ forward osmosis (FO) using aquaporins (AQP)‐based biomimetic membranes and optimize the Cr rejection through response surface methodology (RSM). The initial concentration of draw solution, feed solution, and time was selected as independent variables in order to optimize Cr rejection and water flux. A high Cr rejection efficiency and water flux were achieved under the optimal conditions. These results revealed that the FO process applying an AQP membrane beside the RSM could be considered to treat wastewaters containing heavy metals. [ABSTRACT FROM AUTHOR]