Osmotic energy harvesting using acrylic acid hydrogel PET membrane

In this study, we investigated the osmotic energy harvesting using a cation-selective membrane. The cation-selective membrane was synthesized by the incorporation of acrylic acid hydrogel in a porous support membrane. FTIR analysis and SEM images confirmed the presence of the acrylic acid hydrogel rods inside the porous support material. The exposure of the acrylic acid hydrogel PET (AP) membrane to a concentration gradient culminated in the generation of electric power. The AP membrane was evaluated in regard to the following parameters: E_Diff, I_o, P_max and t₊. The maximum power obtained with the membrane was 1.10 μW at the 40-fold concentration gradient (test area∽ 100 mm²). Increasing the concentration gradient increased the power output. However, a decrease in power output was observed after a certain value of the concentration gradient. An enhancement in power output was noted as the fraction of acrylic acid within the membrane was augmented. Additionally, the cation transference number also increased owing to a high charge density and a reduction in the mesh size. The AP membrane was also investigated in acidic and basic media. The time-dependent study revealed the superior chemical stability of the AP membrane.