Structural manipulation of PES constituents to prepare advanced alternative polymer for ultrafiltration membrane

The Application of Polyethersulfone Ultrafiltration Membranes for Separation of Car Wash Wastewaters: Experiments and Modelling

The wastewater generated as a result of car washes is considered a new source of water. However, recovered water must meet the required quality criteria for reuse. For this purpose, the ultrafiltration (UF) process can be successfully used. The main aim of the present work was to investigate the influence of the membrane's molecular weight cut-off (MWCO) on the UF performance in terms of the fouling phenomenon and retention degree of car wash wastewater. Moreover, for a better understanding of the fouling mechanisms, Hermia's model was used. The experimental studies were conducted with the use of two polyethersulfone (PES) membranes (MWCO of 10 kDa and 100 kDa). It has been noted that the used membranes provided a high-quality permeate and excellent turbidity removal, up to 99%. Moreover, it has been noted that the MWCO membrane has a significant impact on the fouling mechanism. Generally, a much greater intensity of fouling for the membrane with MWCO of 100 kDa was observed. Results obtained in the present study showed that both real wastewaters and the clean solutions used for washing cars cause the fouling phenomenon. It has been proven that rinsing the membranes with water is not sufficient to recover the initial membrane's performance. Hence, periodic chemical cleaning of the membranes was required. Fitting the experimental data to Hermia's model allowed us to indicate that membranes with MWCO of 100 kDa are more prone to intermediate blocking. To sum up, the findings suggest that for the UF of the car wash wastewater, the use of membranes with MWCO equal to 10 kDa is recommended.

Synthesis and properties of polyarylene ether nitrile random copolymer containing naphthalene and biphenyl structure

A novel series of polyarylene ether nitrile (PEN) random copolymers with a higher Tg and better mechanical and electrical properties were synthesized through nucleophilic substitution polycondensation. In the means of adjusting mole ratio of 4,4′-dihydroxybiphenyl (BP) to 2,7-naphthalenediol (ND), the performance of PEN random copolymer could be controlled. The FTIR, SEM, DSC, TGA, AR, intrinsic viscosity, and electrical and mechanical properties were performed on the samples. All the samples exhibited excellent thermal performance with Tg over 210°C, Td5% over 520°C, and heat conduction higher than 0.4 W/m·k. The PEN copolymers when the molar ratio of ND was 15% had the best comprehensive performances, whose Tg was 215°C, Td5% was up to 554.31°C, thermal conductivity was 0.4430 W/m·k, tensile strength was 113.27 MPa, and stable dielectric constant (at frequency from 103 Hz to 106 Hz) was lower than 4. As a result, this PEN copolymer obtained in this paper could provide practical value and possibility in further application in the filed including machine manufacture industry, electronic materials, and automotive industry.