Addressing water scarcity: cationic polyelectrolytes in water treatment and purification

Abstract

Synthetic cationic polyelectrolytes (CPEs) serve as coagulation and flocculation agents in wastewater treatment due to a synergy of inherent electrostatic interactions and hydrophilic properties. In wastewater treatment, CPEs act as coagulation and flocculation agents to aggregate impurities and enable water purification. New health and environmental-related regulations provide motivation for government agencies and industrial companies to reuse wastewater. Chemical structure, molecular weight, charge density and functionality of CPEs provide tailorability for specific purification needs. Cationic polyacrylamides, ammonium-based polymers, poly(allyldimethyl-ammonium chloride) and epichlorohydrin/dimethylamine-based polymers are the most common CPEs used as coagulation and flocculation agents because they are economical and water soluble with tunable charge densities at high molecular weights. Free radical polymerization, step-growth polymerization and post-polymerization modification methods afford each polymer system. This review highlights recent advancements in synthetic methods to yield CPEs, structure−property relationships as related to flocculation efficiency and a summary of their toxicity and environmental impact.

Recent Achievements in Polymer Bio-Based Flocculants for Water Treatment

“…Most synthetic flocculants are remarkably toxic to humans, animals, and aquatic organisms [ 11 , 12 , 13 ]. For example, acrylamide monomer, which can contaminate the polymer in trace amounts, has a dangerous carcinogenic effect [ 14 ].…”

“…For example, acrylamide monomer, which can contaminate the polymer in trace amounts, has a dangerous carcinogenic effect [ 14 ]. It is possible that small amounts of polymers after water treatment will get into the environment in finely divided form or as diluted solution, which creates an additional problem [ 13 ]. This is the reason new biodegradable, safe, and economical substitutes of the conventional agents are sought.…”

Influence of Calcium Binding on Conformations and Motions of Anionic Polyamino Acids. Effect of Side Chain Length

“…Polyelectrolytes, such as anionic poly(amino acids), are widely used in diverse applications including water treatment and purification [ 1 ], anticorrosion agents [ 2 ], drug delivery [ 3 , 4 , 5 , 6 ] and tissue engineering [ 7 , 8 , 9 , 10 , 11 ]. Biodegradable and biocompatible anionic poly(amino acids) are attractive due to their comparative cheapness and ease of high-volume manufacturing.…”

Sustaining our Passion for Sustainability

“…Earth sustainability exemplifies one global grand challenge for the polymer community, and earth sustainability of polymeric materials remains a thematic focus for the journal. [1][2][3][4] However, researchers are often challenged to sustain their passion for the science of sustainability due to many factors, including variable economics, uncertainty in energy calculations, diversity in civil infrastructure, regionally inspired sustainable feed stocks, and the often missing yet essential industry-university partnership. [5][6][7] Our recently introduced Challenges to Industry articles from industrial scientists and engineers are designed to challenge academic researchers to address fundamental technical obstacles and accelerate innovation for global impact.…”

“…Addressing grand challenges in polymer science and engineering demands this synergistic approach, and the journal has recently instituted mechanisms to further nurture this global perspective. Earth sustainability exemplifies one global grand challenge for the polymer community, and earth sustainability of polymeric materials remains a thematic focus for the journal . However, researchers are often challenged to sustain their passion for the science of sustainability due to many factors, including variable economics, uncertainty in energy calculations, diversity in civil infrastructure, regionally inspired sustainable feed stocks, and the often missing yet essential industry‐university partnership .…”