Functional Hydrophilic Membrane for Oil-Water Separation Based on Modified Bio-Based Chitosan-Gelatin

Recent progress and future directions of membranes green polymers for oily wastewater treatment

The preparation, modification and application of green polymers such as poly-lactic acid (PLA), chitosan (CS), and cellulose acetate (CA) for oily wastewater treatment is summed up in this review. Due to the low environmental pollution, good chemical resistivity, high hydrophobicity, and good capacity for water-oil emulsion separation of the presented polymers, it then highlights the various membrane production methods and their role in producing effective membranes, with a focus on recent advances in improving membrane properties through the addition of various Nano materials. As a result, the hydrophilic/hydrophobic properties that are critical in the oil separation mechanism are highlighted. Finally, it looks at the predictions and challenges in oil/water separation and recovery. These ideas are discussed with a focus on modern production methods and oil separation proficiency.

Pickering Emulsions Stabilized by Chitosan/Natural Acacia Gum Biopolymers: Effects of pH and Salt Concentrations

In this study, chitosan (CT) and naturally occurring acacia gum (AG) blends were employed as emulsifiers to form a series of emulsions developed from diesel and water. Effects of pH level (3, 5, 10, and 12) and various NaCl salt concentrations (0.25-1%) on the stability, viscosity, and interfacial properties of CT-(1%)/AG-(4%) stabilized Pickering emulsions were evaluated. Bottle test experiment results showed that the stability indexes of the CT/AG emulsions were similar under acidic (3 and 5) and alkaline (10 and 12) pH media. On the other hand, the effects of various NaCl concentrations on the stability of CT-(1%)/AG-(4%) emulsion demonstrated analogous behavior throughout. From all the NaCl concentrations and pH levels examined, viscosities of this emulsion decreased drastically with the increasing shear rate, indicating pseudoplastic fluid with shear thinning characteristics of these emulsions. The viscosity of CT-(1%)/AG-(4%) emulsion increased at a low shear rate and decreased with an increasing shear rate. The presence of NaCl salt and pH change in CT/AG solutions induced a transformation in the interfacial tension (IFT) at the diesel/water interface. Accordingly, the IFT values of diesel/water in the absence of NaCl/CT/AG (without emulsifier and salt) remained fairly constant for a period of 500 s, and its average IFT value was 26.16 mN/m. In the absence of salt, the addition of an emulsifier (CT-(1%)/AG-(4%)) reduced the IFT to 16.69 mN/m. When the salt was added, the IFT values were further reduced to 12.04 mN/m. At low pH, the IFT was higher (17.1 mN/M) compared to the value of the IFT (10.8 mN/M) at high pH. The results obtained will help understand the preparation and performance of such emulsions under different conditions especially relevant to oil field applications.