Novel smart composite materials for industrial wastewater treatment and reuse

Abstract: With the current levels of industrial development it is very difficult to prevent organic pollutants and toxic heavy metals from contaminating water. Thus purification of contaminated industrial water and its reuse is a global concern. The present study highlights application of a novel standalone technology in the form of polymers that efficiently extract a range of organic and inorganic impurities simultaneously for reuse of industrial effluent. Previous studies have focused on water soluble synthetic polymers for removal of organic contaminants, while biodegradable polymers are being used for extraction of toxic metals from water. Our earlier reports already describe a combination of synthetic and natural polymers with the ability to eliminate organic and inorganic spiked impurities from water on a lab scale. In the present work a series of novel smart composite materials have been synthesized and fully characterized. The avant-garde novelty of these materials for simultaneous removal of organic impurities such as phenols, anhydrides, textile dyes, pesticides, herbicides, antibiotics and inorganic heavy metals has been demonstrated and the novel polymers have shown a removal efficiency of more than 90% for each of the contaminants. Furthermore, the established 4-cycle reusability and an extensive reduction in levels of chemical oxygen demand suggests these materials would act as an improvement to the current methods for treating effluent water. The high reproducibility in synthesis, properties and elimination spectrum brands them as promising materials for industrial water remediation and reuse

Grafted Pullulan Derivatives for Reducing the Content of Some Pesticides from Simulated Wastewater

The goal of the current article was to obtain data regarding the application of a series of grafted pullulan derivatives, as flocculating agents, for removal of some pesticide formulations from model wastewater. The pullulan derivatives are cationic polyelectrolytes, with various content and length of grafted poly[(3-acrylamidopropyl)-trimethylammonium chloride] chains onto the pullulan (P-g-pAPTAC)]. The commercial pesticides are either fungicide (Bordeaux Mixture) (BM) or insecticides (Decis (Dc)—active ingredient Deltamethrin, Confidor Oil (CO)—active ingredient Imidacloprid, Confidor Energy (CE)—active ingredients Deltamethrin and Imidacloprid and Novadim Progress (NP)—active ingredient Dimethoate). The removal efficiency has been assessed by UV-Vis spectroscopy measurements as a function of some parameters, namely polymer dose, grafted chains content and length, pesticides concentration. The P-g-pAPTAC samples showed good removal efficacy at doseop, more than 94% for BM, between 84 and 90% for DC, CO and CE and around 93% for NP. The maximum percentage removal decreased with the pesticides (DC, CO, CE, NP) concentration declining; no effect of BM concentration in suspension on its removal efficiency process has been noted. Differences indicated by zeta potential and particle size distribution measurements regarding the pesticides removal mechanisms by pullulan derivatives (charge neutralization, bridging, etc.) are discussed

Charge density, solvent polarity and counterion nature effects on the solution properties of some polycations

The electrolytic cond. and soln. viscosity of some strong polycations, which possess the ammonium quaternary centers either attached to an acrylic macromol. chain (polycation PDMAEMQ type), or in the backbone (polycation PCA type), have been measured to identify how charge d., polyelectrolyte concn., solvent polarity as well as counterion nature influence the ultimate soln. properties. The investigations reveal for all polycations an increase of the equiv. cond. with decreasing concn. The onset of the strong increase shifts to lower concn. if the charge d. augments. Polyelectrolyte behavior was obsd. for PCA5D1 in the mixt. of water/methanol for all solvent compns. employed and in the mixt. of water/acetone up to 60 vol. % of acetone content. At all exptl. concns. the reduced viscosity decreases with the dielec. const. of the mixed solvent. Furthermore, the specific interaction between several mono- and divalent counterions with some of these polycations was clearly proved by conductometric measurements. [on SciFinder (R)

Macroporous 3D Chitosan Cryogels for Fastac 10EC Pesticide Adsorption and Antibacterial Applications

The pesticide pollution of surface water and wastewater has been recognized as a major worldwide concern due to their persistence in the aquatic environment and the potential adverse effects on human, flora, and fauna health. Apart from pesticides, bio-contamination with various bacterial populations leads to waterborne diseases. Hence, it becomes vital to remove the above-mentioned pollutants from water using a suitable process. Consequently, our study emphasized the potential benefits of a highly porous, chemically cross-linked 3D chitosan (CSGA) cryogel in the removal of pesticides and bacteria. The CSGA sponges were prepared using a facile and cost-effective approach that consisted of a three-step cryogenic process: (i) freezing at −18 °C, (ii) storage in a frozen state for a certain period, and (iii) thawing at room temperature. Batch adsorption experiments were performed under different environments, where the effects of several parameters, such as pH, contact time, and initial pollutant concentration were evaluated to identify the appropriate adsorption conditions for maximum pesticide removal. The CSGA-based cryogel sponges exhibited a theoretical maximum adsorption capacity of 160.82 mg g−1 for the Fastac 10EC pesticide and very good recyclability at room temperature. In addition, the antibacterial activities of these sponges were also investigated against various bacterial pathogens. The rates of killing Escherichia coli, Listeria monocytogenes, and Staphylococcus aureus were close to 82%, 100%, and 99%, respectively. These results demonstrated that CSGA cryogels could be efficiently used in water remediation and find applications in the removal of pesticides and disinfection