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In present study the biodegradation of partially hydrolyzed polyacrylamide (HPAM) by bacterial strains isolated from Omani oil fields was analyzed. HPAMs are extensively used in oil fields for enhanced oil recovery operations. The produced water after polymer flooding poses grave ecological problems, such as it could raise the difficulty of oil–water separation, producing toxic acrylamide that degrades naturally, which threatens the local environment. Biodegradation of HPAM by microbes may be an efficient way to solve those problems. Microbial biodegradation is considered an environmentally friendly safe technique. The isolation of microbes that are able to degrade HPAM from the oil field produced water was investigated in this study. The bacterial isolates were identified by MALDI-Biotyper and the biodegradation of HPAM was analyzed by LC-MS and reduction in viscosity by rheometer. Two HPAM degrading bacterial strains Bacillus sp. (NP-10) and Chelatococcus sp. (NP-11) were isolated from the polymer-flooding produced water. The removal efficiency of HPAM based on shear viscosity for NP10 andNP11 were 59.9% and 58.4%, respectively after 9-days treatment period, at pH 7.1, 40 °C and 160 rpm. The addition of glucose (0.5 g/l) did not improve the HPAM degradation for NP11. However, the degradation percentage by NP10 reached to 68.8%. HPAM samples after bacterial biodegradation were analyzed by LC-MS. The results showed the presence of acrylamide monomers in the culture after biodegradation. Three other isolated strains were identified as NP-9, NP-2 and NP-8 were able to reduce the concentration of acrylamide significantly. Present findings proved that both Bacillus sp. (NP-10) and Chelatococcus sp. (NP-11) could be suitable candidates for biodegradation of HPAM and NP-9, NP-2 and NP-8 strains as potential candidates for reducing the acrylamide concentrations, as an environmental friendly approach.

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Zn x Cd 1−x S solid solutions with controlled morphology have been successfully synthesized by a facile solution-phase method. The prepared samples were characterized by X-ray powder diffraction (XRD), UV-vis diffuse reflectance spectra, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The photocatalytic activity of Zn x Cd 1−x S was evaluated in the 2,4,6-trichlorophenol (TCP) degradation and mineralization in aqueous solution under direct solar light illumination. The experiment demonstrated that TCP was effectively degraded by more than 95% with 120 min. The results show that ZnS with Cd doping (Zn x Cd 1−x S) exhibits the much stronger visible light adsorption than that of pure ZnS, the light adsorption increasing as the Cd 2+ doping amount. These results indicate that Cd doping into a ZnS crystal lattice can result in the shift of the valence band of ZnS to a positive direction. It may lead to its higher oxidative ability than pure ZnS, which is important for organic pollutant degradation under solar light irradiation. Furthermore, the photocatalytic activity studies reveal that the prepared Zn x Cd 1−x S nanostructures exhibit an excellent photocatalytic performance, degrading rapidly the aqueous 2,4,6-trichlorophenol solution under solar light irradiation. These results suggest that Zn x Cd 1−x S nanostructure will be a promising candidate of photocatalyst working in solar light range.