Preparation of a thin-film nanocomposite forward osmosis membrane for the removal of organic micro-pollutants from aqueous solutions

Preparation of a cellulose acetate membrane using cigarette butt recycling and investigation of its efficiency in removing heavy metals from aqueous solution

This study investigated the recycling of freshly-smoked cigarette butts (FCBs) and unsmoked cigarette filters (UCFs) into a cellulose acetate (CA) membrane. The both samples were prepared by means of a combination of seven cigarette brands, and the phase inversion method was used to recycle each sample into a membrane using N-methyl-2-pyrrolidone. The efficiency of the prepared membranes for the removal of chromium, cadmium, and lead from an aqueous solution in a forward osmosis reactor was investigated. The results showed that the both membranes had a smooth surface and macrovoids. The flux of the prepared membranes from the UCFs and FCBs recycling were 14.8 and 13.2 LMH, respectively. The porosity and reverse salt of the UCFs membrane were 61% and 3.5 gMH, while those for FCBs membrane were 58% and 3.9 gMH. The observed metal removal efficiency of the both membranes was in the range of 85 to 90%. However, increasing the concentration of metals up to five times caused a slight decrease in the removal efficiency (less than 5%).

Innovative progress in graphene derivative-based composite hybrid membranes for the removal of contaminants in wastewater: A review

Graphene derivatives (graphene oxide) are proved as an innovative carbon materials that are getting more attraction in membrane separation technology because of its unique properties and capability to attain layer-to-layer stacking, existence of high oxygen-based functional groups, and generation of nanochannels that successively enhance the selective pollutants removal performance. The review focused on the recent innovations in the development of graphene derivative-based composite hybrid membranes (GDHMs) for the removal of multiple contaminants from wastewater treatment. To design GDHMs, it was observed that at first GO layers undergo chemical treatments with either different polymers, plasma, or sulfonyl. After that, the chemically treated GO layers were decorated with various active functional materials (either with nanoparticles, magnetite, or nanorods, etc.). By preparing GDHMs, properties such as permeability, porosity, hydrophilicity, water flux, stability, feasibility, mechanical strength, regeneration ability, and antifouling tendency were excessively improved as compared to pristine GO membranes. Different types of novel GDHMs were able to remove toxic dyes (77-100%), heavy metals/ions (66-100%), phenols (40-100%), and pharmaceuticals (74-100%) from wastewater with high efficiency. Some of GDHMs were capable to show dual contaminant removal efficacy and antibacterial activity. In this study, it was observed that the most involved mechanisms for pollutants removal are size exclusion, transport, electrostatic interactions, adsorption, and donnan exclusion. In addition to this, interaction mechanism during membrane separation technology has also been elaborated by density functional theory. At last, in this review the discussion related to challenges, limitations, and future outlook for the applications of GDHMs has also been provided.

A Comprehensive Review on Forward Osmosis Water Treatment: Recent Advances and Prospects of Membranes and Draw Solutes

Forward osmosis (FO) is an evolving membrane separation technology for water treatment and reclamation. However, FO water treatment technology is limited by factors such as concentration polarization, membrane fouling, and reverse solute flux. Therefore, it is of a great importance to prepare an efficient high-density porous membrane and to select an appropriate draw solute to reduce concentration polarization, membrane fouling, and reverse solute flux. This review aims to present a thorough evaluation of the advancement of different draw solutes and membranes with their effects on FO performance. NaCl is still widely used in a large number of studies, and several general draw solutes, such as organic-based and inorganic-based, are selected based on their osmotic pressure and water solubility. The selection criteria for reusable solutes, such as heat-recovered gaseous draw, magnetic field-recovered MNPs, and electrically or thermally-responsive hydrogel are primarily based on their industrial efficiency and energy requirements. CA membranes are resistant to chlorine degradation and are hydrophilic, while TFC/TFN exhibit a high inhibition of bio-adhesion and hydrolysis. AQPs are emerging membranes, due to proteins with complete retention capacity. Moreover, the development of the hybrid system combining FO with other energy or water treatment technologies is crucial to the sustainability of FO.

Forward osmosis dewatering of seawater and pesticide contaminated effluents using the commercial fertilizers and zinc-nitrate blend draw solutions

Fertilizer driven forward osmosis (FDFO) process would be feasible due to the possible prevention of the drainage of dewatered and concentrated pesticide effluent from agricultural pesticide industries to the environment. Instead, it would be possible to return the concentrated pesticide solution to the processing cycle, and on the other hand, employ directly the obtained diluted fertilizer draw solution for irrigation. This study investigated the performance of zinc-nitrate/amino-acids blends as fertilizer type draw solution, and distilled water, saline water (seawater), and synthetic wastewater containing pesticides as feed. The results indicated that the synergetic effect of blended type fertilizer presented significantly higher osmotic pressure and water flux than the sum of their individual ones, especially when the amount of amino acid increased. Conversely, an ignorable reverse flux of blended fertilizer draw solute was observed. The fertilizer blend with a molar ratio of 1:6 zinc-nitrate/amino-acid achieved the higher average fluxes of 34.7 and 23.92 L/m²h from distilled and saline waters compared to common draw solutions such as metal salts. Furthermore, the FDFO exhibited a high rejection (over 99%) of bentazon and imidacloprid in feed solutions compared to other agricultural pesticides due to their larger molecular weight and molecular size. The applied FDFO represented a significant reduction in specific energy consumption (from 0.17 to 0.049 kWh/m³) in a bench-scale setup as compared to the RO process almost at the same water permeation flux and the rejection of bentazon.