CELLULOSE BASED FOAM WITH IONIC FUNCTIONALITY: SYNTHESIS AND APPLICATION IN WASTEWATER PURIFICATION FROM TOXIC METALS
Date
2022-08-28
Authors
AbuAlrob, Haneen
Journal Title
Journal ISSN
Volume Title
Publisher
جامعة النجاح الوطنية
Abstract
Abstract
Background: The excessive applications of chemicals increased the load of contaminants in water. Organic, heavy metals ion, and inorganic contaminants pose a serious risk to creatures' life. heavy metal ions are one of the most harmful common contaminants. Scientists devoted their effort to finding an efficient, economic, commercially available, and environmentally friendly way to remove contaminants from water.
Objectives: In this study, we benefit from Polyurethane foam (PUF) characteristics. PUF is easy to prepare and use in water purification. Elastic porous structure, controllable pore structure, adjustable shape, simple preparation process, high stability, and high adsorption/desorption rate. These properties make it very suitable for use as an adsorbent material for toxic metal ions. The lack of metal-binding groups in PUF limited its use in wastewater purification. PUF modified with an ionic functional group that is covalently attached to it will be synthesized and used as a metal adsorbent.
Methodology: PUF preparation was carried out by polymerizing the diisocyanate compound with oxidized cellulose. The first step involved reacting cellulose with sodium periodate to produce dialdehyde cellulose. Produced dialdehyde cellulose was reacted with para-aminobenzoic acid to form a Schiff base. Schiff base was reduced by sodium borohydride to form cellulose amino benzoic acid. At the last step, a diisocyanate compound was added to form a foam with a 3D structure with carboxyl functionality. The presence of the carboxylate and amino benzoic acid groups in addition to the other PUF properties mentioned above makes the target foam novel for wastewater purification. The prepared polymers were characterized by using TGA, and FT-IR. The produced foam was used in extracting metal ions form wastewater. Optimum adsorption conditions for wastewater purification process using the prepared cellulose PUF polymers was detected. The adsorption conditions that lead to the highest efficacy were determined by running the extraction at various parameters such as: pH, contact time, temperature ℃, dosage, and initial metal ion concentration.
Results: The effect of each parameter was evaluated by varying the parameter values while keeping others constant. The targeted parameters that lead to the highest efficacy were determined to be pH 7.0 and 9.0, contact time 30 and 25 min, temperature 15 and 20, dosage 250 mg, and initial metal ion concentration 15.0 and 20.0 ppm for PPUF and HMPUF respectively. An atomic absorption spectroscopy instrument was used to determine the concentration of lead after applying the polymer under certain conditions. After detecting the ideal parameters, the prepared polymers were applied to a real-life sample of wastewater. Under the optimum conditions, the efficiency of the polymers in lead removal was tested. Inductively Coupled Plasma Mass Spectrometer ICP-MS was used to determine the concentration of contaminants in the real-life sample (sewage water) after and before applying the polymer. the Langmuir model was fitted to the equilibrium adsorption data. Van't Hoff plot was used to determine ΔH°(KJ/mol), ΔS° (J/mol.K), and ΔG°( KJ/mol) values they were -7.693, and -31.44, and 9.53, -28.725, -107.2 and 32.44 for PPUF & HMPUF- NCC respectively. The results indicate that the adsorption process is spontaneous at room temperature. Kinetic study showed that the process obeys pseudo second-order the R2 value for the two polymers are very close to1.
Conclusion: After detecting the optimum conditions polymers were applied to a real sample and the two polymers show excellent efficiency in the removal of heavy metals.
Keywords: heavy metals, water pollution, cellulose, polyurethane foam, adsorption.
Description
This Thesis is Submitted in Partial Fulfillment of the Requirements for the Degree of Master of Chemistry, Faculty of Graduate Studies, An-Najah National University, Nablus - Palestine.
Keywords
CELLULOSE BASED FOAM WITH IONIC FUNCTIONALITY: SYNTHESIS AND APPLICATION IN WASTEWATER PURIFICATION FROM TOXIC METALS