Organic removal from coal-to-chemical brine by a multistage system of adsorption-regeneration and electrochemically driven UV/chlorine processes

Zirconium-embedded ceramic membrane catalyzed moderate ozonation: dual-function synergy for simultaneous control of algal odorants and membrane fouling in water treatment

The integration of ozone with ceramic membrane offers a promising approach for treating algae-laden water but presents challenges in balancing oxidation efficacy with the preservation of cell integrity. In this study, catalytic ceramic membrane system embedded with zirconium (Zr) developed achieved 58.4 % removal of 2-methylisoborneol and 68.2 % removal of geosmin through dehydration and ring opening via hydroxyl radical-mediated degradation pathways generated in situ on the membrane under optimal ozone dosage. It is worth noting that the mild ozone concentration increased the hydrophobic interaction energy between algal cells and the filter cake layer from -13.7 mJ/m2 to -0.3 mJ/m2, thereby effectively reducing the deposition of pollutants on the membrane. By controlling oxidative intensity, the ceramic membrane's reversible and irreversible resistances were decreased by 86.7 % and 80.1 %, respectively, while maintaining >95 % algal cell integrity. This study establishes a mild catalytic oxidation paradigm for ceramic membrane-based algae-laden water treatment, achieving simultaneous degradation of odorants and membrane fouling control.

The mechanism of microbial sulfate reduction in high concentration sulfate wastewater enhanced by maifanite

Excessive sulfate levels in water bodies pose a dual threat to the ecological environment and human health. The microbial removal of sulfate encounters challenges, particularly in environments with high sulfate concentrations, where the gradual accumulation of sulfide hampers microbial activity. This study focuses on elucidating the mechanisms underlying the enhancement of microbial sulfate reduction in high-concentration sulfate wastewater through a comparative analysis of maifanite and zeolite biostimulants. The investigation reveals that zeolite primarily facilitates microbial growth by providing attachment sites, while maifanite augments sulfate-reducing bacteria (SRB) activity through the release of active substances such as Mo, Ca, and Cu. The addition of maifanite proves instrumental in enhancing microbial activity, manifesting as increased microbial load and protein production, augmented extracellular polymer generation, accelerated electron transfer, and facilitated microbial growth and biofilm formation. Noteworthy is the observation that the combined application of maifanite and zeolite exhibited a synergistic effect, resulting in a 167 % and 68 % increase in sulfate reduction rate compared to the utilization of maifanite (0.12 d-1) or zeolite (0.19 d-1) in isolation. Within this synergistic context, the relative abundance of Desulfobacteraceae reaches a peak of 15.4 %. The outcomes of this study corroborate the distinct promotion mechanisms of maifanite and zeolite in microbial sulfate reduction, offering novel insights into the application of maifanite in the context of high-concentration sulfate removal.

Adsorption and desorption behavior of Zn2+ in a flow-through electrosorption reactor

As heavy metal industrial wastewater increases in volume and complexity, we need more efficient, cheaper, and renewable technologies to curb its environmental impact. Compared to advection electrosorption, through-flow electrosorption is a hotspot technique that makes more efficient use of the adsorption capacity of activated carbon fiber mats. A cascade flow-through electrosorption assembly based on activated carbon fiber was used to obtain the best adsorption of Zn2+ in water at a voltage of 2 V, pH value of 8, plate spacing of 3 mm, and temperature of 15°C. The process is more closely fitted to the secondary adsorption kinetic equation and the Langmuir equation. The adsorption capacity of the module decreases at a progressively slower rate with the number of cycles and will eventually retain 75% of its peak value with significant regenerability. The study of this module can provide technical support for treating heavy metal wastewater.