Coagulation/flocculation (CF) by use of alum and cationic polymer polyDADMAC, was performed as a pretreatment for remediation of oil sands process-affected water (OSPW). Various factors were investigated and the process was optimized to improve efficiency of removal of organic carbon and turbidity. Destabilization of the particles occurred through charge neutralization by adsorption of hydroxide precipitates. Scanning electron microscope images revealed that the resultant flocs were compact. The CF process significantly reduced concentrations of naphthenic acids (NAs) and oxidized NAs by 37 and 86%, respectively, demonstrating the applicability of CF pretreatment to remove a persistent and toxic organic fraction from OSPW. Concentrations of vanadium and barium were decreased by 67-78% and 42-63%, respectively. Analysis of surface functional groups on flocs also confirmed the removal of the NAs compounds. Flocculation with cationic polymer compared to alum, caused toxicity toward the benthic invertebrate, Chironoums dilutus, thus application of the polymer should be limited.

Petroleum coke (PC) is a waste by-product generated during the oil upgrading processes by the petroleum industry. The continuing accumulation of large quantities of PC requires the development of innovative strategies for the effective utilization of this carbon-rich material. In this study, PC was used for the removal of naphthenic acids (NAs) and acid-extractable fraction (AEF) from oil sands process-affected water (OSPW), generated during the oil refining process. A systematic study on the adsorption of organic fractions, vanadium leaching from PC, adsorption mechanisms, and the effect of physico-chemical characteristics of the PC on adsorption process was performed. Physico-chemical properties of PC were determined by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy, and Brunauer-Emmett-Teller surface area analysis. AEF and NAs removals of 60 and 75 %, respectively, were achieved at PC dose of 200 g/L after 16 h of contact. FT-IR and TGA analysis of PC suggested the physisorption of organic compounds onto the surface of PC. The calculated mean free energy of adsorption (E \ 8 kJ/mol) also indicated the physisorption of organics to the PC surface. The hydrophobic interactions between the NAs and the PC were suggested as the dominant adsorption mechanisms. The vanadium release occurred when PC was mixed with OSPW and vanadium concentration increased with an increase in the PC dose. Speciation analysis indicated that the vanadium leached was predominantly vanadium (V) and insignificant amount of vanadium (IV) was also detected.

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We present an electrochemical advanced oxidation process (eAOP) reactor employing expanded graphite, potassium iodide (KI), and electrical current, which demonstrates an exceptionally high rate of inactivation of E. coli (6log reduction in viable cells) at low current density 0.6 mA/cm^2), with low contact time (5 minutes) and low concentration of KI (10 ppm). Operando X-ray fluorescence mapping is used to show the distribution of iodine species in the reactor, and operando X-ray absorption spectroscopy in the anodic chamber reveals iodine species with higher effective oxidation state than periodate. Operando electrochemical measurements confirm the conditions in the anodic chambers are favourable for the creation of highly oxidized iodine products. The killing efficiency of this new eAOP reactor far exceeds that expected from either traditional iodine-based electrochemical water treatment or advanced oxidation systems alone, a phenomenon that may be associated with the production of highly oxidized iodine species reported here.

We present an electrochemical advanced oxidation process (eAOP) reactor employing expanded graphite, potassium iodide (KI), and electrical current, which demonstrates an exceptionally high rate of inactivation of E. coli (10 6 or 6log 10 reduction in viable cells) at low current density (0.12 mA/cm 2 ), with low contact time (5 minutes) and low concentration of KI (10 ppm; 0.06 mM)). Operando X-ray fluorescence mapping is used to show the distribution of iodine species in the reactor, and operando X-ray absorption spectroscopy in the anodic chamber reveals iodine species with higher effective oxidation state than IO 4 -. Operando electrochemical measurements confirm the conditions in the anodic chambers are favourable for the creation of highly oxidized iodine products. The killing efficiency of this new eAOP reactor far exceeds that expected from either traditional iodine-based electrochemical water treatment or advanced oxidation systems alone, a phenomenon that may be associated with the production of highly oxidized iodine species reported here.