Novel thermoresponsive assemblies of co-grafted natural and synthetic polymers for water purification

Abstract

16Water contamination is a global concern and its purification is essential to ensure a healthy life. 17The current approach to purify water is reduction of impurities to acceptable levels. One of the 18 ways in which this can be achieved is by use of water soluble synthetic polymers that are able to 19 extract organic contaminants, while polymers that are biodegradable can be used to extract toxic 20 metals from water. In this paper we present a blend of composite polymers that are able to 21 extract both these types of contaminants (organic and metallic) simultaneously by the principle of 22 adsorption at LCST. These composite polymers have been synthesized by grafting polymers such 23 as poly(N,N-diethylacrylamide), poly(N-isopropylacrylamide) and poly(N-vinylcaprolactum) on 24 to the natural polymer chitosan or its derivatives giving smart graft polymeric assemblies (GPA). 25One such graft polymer, GPA-2 exhibits excellent adsorption properties and is able to remove 26 metal ions such as cadmium, cobalt, copper, lead, iron as well as organic impurities like 27 chlorophenol and phthalic anhydride. Studies reveal that 6 mg/ml of the polymer GPA-2 is able to 28 effect a 100% removal of the two organic impurities -chlorophenol (50 ppm) and phthalic 29 anhydride (70 ppm) from water, while complete removal of the three heavy metal ions (Cu +2 , 30 Co+2 and Cd +2

Novel smart composite materials for industrial wastewater treatment and reuse

“…This shift of LCST values is due to the increase/decrease in the hydrophilic properties of the material owing to addition or change of functional groups. A similar shift in the LCST values was evident in our previous paper and was confirmed using DSC [4].…”

“…Further, the molecular weights of the final smart composite materials were determined using the following equation [4], GR-grafting ratio, W g -final weight of grafted polymer, W p -weight of pullulan, MW homo -molecular weight of homopolymer, MW p -molecular weight of pullulan, MW g -molecular weight of graft polymer.…”

“…The chemical oxygen demand is a direct measure of the load of dissolved organic substances and impurities present in effluents. The standard COD titration method was used for determination of dissolved organic load of the effluent samples and was calculated by the following equation, (4) Proportional impurity removal(%) = C o − C e C o × 100 Industrial effluent water Fungicides, chemicals, organic matter COD reduction by titration A 500 ppm solution of potassium hydrogen phthalate (KHP) was used as the standard for calibration and standardization of the titrimetric method.…”

“…This is in contrast to biodegradable polymers that have been reported as chelating agents and thus adsorb inorganic water soluble impurities and dyes [9] from effluent but lack the shelf life for prolonged use. Therefore, a combination of both the polymers as a graft not only extracts organic and inorganic impurities simultaneously but also imbibes biodegradability to the overall polymer [4]. Hence, the current paper demonstrates co-polymerization or grafting of a temperature responsive synthetic polymer onto a biodegradable polymer to generate novel smart composite materials for exclusive extraction of phenols, anhydrides, textile dyes, pesticides, herbicides, antibiotics and inorganic heavy metals simultaneously from water.…”

“…Hence, there is need for a unique, safe, innovative and cost-effective technology that can be readily assimilated in the current industrial setup. Our earlier reports, describe the applicability of one such technology using smart biodegradable polymers that remove hazardous organic chemicals, metal ions and dyes from spiked water under the influence of temperature on a lab scale [4,5]. In continuation of the earlier proceedings, in this paper we present an innovative technology in the form of a novel series of temperature responsive biodegradable materials as composites that have ability to efficiently extract the dissolved metal ions and impurities present in pharmaceutical, chemical agrochemical and textile industrial effluents.…”