Regenerative macroporous polyzwitterionic gels for brackish/sea water desalination

• Published in: Desalination Vol. 535; p. 115801
• Main Authors: Bairagi, Ujjawal, Jacob, Josemon
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.08.2022
• Subjects: Absorption; Desalination; Polyzwitterionic gels; Regeneration; Salts; Polyzwitterionic gels; Regeneration; Salts; Absorption; Desalination
• ISSN: 0011-9164; 1873-4464
• DOI: 10.1016/j.desal.2022.115801

Ensuring the availability of clean water is one of the most critical sustainable development goals. To contribute to this objective, we report on a novel approach for desalination of brackish/sea water using regenerative, highly porous, thermally stable polyzwitterionic gels (labeled PZG-1, PZG-2, PZG-3, and PZG-4). The synthesized PZGs were used for the removal of commonly found salts from water by electrostatic interaction. The effect of various anions and cations, crosslink density in PZGs, and competitive absorption were systematically investigated. The maximum absorption capacity observed was ~97% and ~89% for I− anion and K+ cation, respectively. Regeneration studies demonstrated that the gels could be reused for more than 5 cycles with ~93% retention of absorption capacity. Our approach, when extended to sea and tap water samples, showed ~87% and 89% reduction in conductivity. Utilizing PZGs is a promising alternative to traditional processes for the desalination of water, as the results from this study show their high efficiency for the removal of salts from wastewater even at very low concentration. Moreover, their efficient and ease of synthesis from relatively inexpensive raw materials, reusability, and the desalination process being more energy efficient in comparison with conventional techniques make this approach unique and highly desirable. [Display omitted] •Regenerative and highly efficient polyzwitterionic gels capable of desalination have been developed.•The gels were found to be very efficient for salt removal from water with up to 97% absorption capacity.•The absorption capacity of PZGs was found to be maximum for I− anions (~97%) and K+cations (~89%).•Desalination studies of sea and tap water samples show ~87% and 89% reduction in conductivity of these solutions.•Regeneration studies showed that the gels could be reused for more than 5 cycles with ~93% retention of absorption capacity.