POLYMER WITH A DUAL ADSORPTION SITES: DESIGN, SYNTHESIS AND PURIFICATION OF POLLUTED WTAER FROM HEAVY METALS AND TOXIC ANIONS
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Date
0202-04-03
Authors
Raneem Ahmad Abu Aysheh
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Abstract
Demand for clean is increasing due to the increase in population. Recycling of contaminated wastewater could be an answer for this issue. Wastewater is contaminated with a variety of toxic materials depending on the contamination source.
The pollutants mainly include metal ions and organic matters that are released from various sources such as medical, plumbing, agricultural, body care products, household chemicals, and industries. Among the toxic heavy metals that raise a serious concern are Cr²⁺, Pb²⁺, Hg²⁺, Cd²⁺, and others that are harmful to creatures.
To remove hazardous heavy metals' pollutants and enhance water quality, researchers used various adsorbent that are polymer based. Modifying existing polymers could be the simplest and most effective way to generate a low-cost adsorbent with high efficiency against metals and hazardous organic compounds.
Among all developed techniques, the adsorption removing approach has attracted the most attention. It has been particularly interesting to develop a superior adsorbent demonstrating a high adsorption capacity and low cost for removing various pollutants from contaminated waters. This study aims to develop cellulose with multi coordination site and zwitterionic functionality.
This study was planned to generate cellulose with multi coordination site and zwitterionic functionality. These criteria make it superior adsorbent for application in purification of polluted wastewater.
The target cellulose was designed to have coordination sites for toxic heavy metals and toxic anions such as nitrate. The method of making the polymer comprises three steps: the first step involves adding an aldehyde functionality to cellulose powder by oxidation (Cell-Ald). In the second step Cell-Ald was crosslinked with a polyamine such 1,4-pheneylendiamine (PPD) to produce a 3D structure with multi coordination site, which then will be reacted with 1,4-butane sultone to form the target polymer cellulose with zwitterionic functionality (Cell-3D-ZWI). The polymer structure was confirmed by FT-IR.
The polymer was evaluated for their ability to adsorb Pb²⁺ ions. The percentage of metal adsorption was investigated as a function of Temperature, pH, adsorbent dosage, contact time, and initial concentration of metal ions. The high efficiency in adsorbing heavy metals from wastewater, with the maximum adsorption result for Pb²⁺ being 97.43% at pH ≈7.21, adsorbent dosage =20 mg, initial concertation of metal ion =10 ppm, contact time =20 min and temperature =20°C.
In addition, the adsorption isotherm, kinetics, and thermodynamics were measured. The thermodynamic parameters of Pb²⁺ adsorption is spontaneous (ΔG°<0), exothermic process (ΔH°<0) and the reaction occurs spontaneously at low temperatures (ΔS°<0). All adsorption processes follow the pseudo- second order adsorption kinetics model (R²= 0.99), which was established by the adsorption parameters, and these adsorptions were matched with the Freundlich isotherm of adsorption (R²=0.89).
The target compound was prepared and identified by IR spectroscopy, it has good thermal stability, it adsorbed metals from wastewater at high efficiency.
Keywords: Cellulose, Water pollution, Wastewater treatment, Heavy metal, Lead, p-Phenylenediamine, 1,4-butane sultone, Zwitterions.