Surface-Modified Magnetic Nanoparticles for Produced Water Purification

Abstract

The oil and gas sector generate large amounts of produced water (PW) that contains various organic and inorganic contaminants (e.g. heavy metals, organic materials, inorganic compounds and phenols). PW discharge puts the marine ecosystem in danger, therefore it must be appropriately treated. One of the best methods for significantly lowering pollutant concentration is adsorption. An effective adsorbent should be non-toxic, reasonably priced, and environmentally acceptable and can be recycled and reused. Therefore, this work aims at investigating the efficiency of polymer- silica coated magnetic nano particles (PAM/SiO2/MNPs) for effective PW treatment, The thesis structure was arranged to investigate the efficiency of MNPs, Polyacrylamide polymer (PAM), MNPs silica coated and their combinations for the treatment of PW. Furthermore, adsorption isotherm and kinetics were studied for the PAM/SiO2/MNPs. Results revealed that the optimal turbidity and %COD removals of 95% and 97.8% were achieved at a MNP dose of 200 mg/L. Maximum TS removal of 13.5% occurred at 400 mg/L. 30 ml/L showed a TS and turbidity removals of 20.1% and 93.7%, respectively, while 200 mg/L of SiO2/MNPs showed 97.3% of %turbidity and 90% of %TS removals. Up to 1000 mg/L SiO2/MNPs were required to achieve 87.3% COD removal . Incorporating PAM as a second layer on SiO2/MNPs (PAMMNPSi 2) achieved 76.0% TS removal at a dose of 200 mg/L. 98.7% of turbidity and 82.9% COD removals were achieved using 100 mg/L PAMMNPSi 1, reducing the COD of the PW from 88,000 to 15,040 mg/L. Freundlich and Pseudo second-order models were found to be the best fit for the experimental data of PAMMNPSi 2. Freundlich and the second order constants of the PAMMNPSi 1 were determined to be 480618 (mg/g)(L/mg)1/n), 7.9x10-4 min-1.