Comparative study of the removal of sulfate by UASB in light and dark environment.

At present, the application of sewage treatment technologies is restricted by high sulfate concentrations. In the present work, the sulfate removal was biologically treated using an upflow anaerobic sludge blanket (UASB) in the absence/presence of light. First, the start-up of UASB for the sulfate removal was studied in terms of COD degradation, sulfate removal, and effluent pH. Second, the impacts of different operation parameters (i.e., COD/SO42- ratio, temperature and illumination time) on the UASB performance were explored. Third, the properties of sludge derived from the UASB at different time were analyzed. Results show that after 28 days of start-up, the COD removal efficiencies in both the photoreactor and non-photoreactor could reach a range of 85-90% while such reactors could achieve > 90% of sulfate being removed. Besides, higher illumination time could facilitate the removal of pollutants in the photoreactor. To sum up, the present study can provide technical support for the clean removal of sulfate from wastewater using photoreactors.

Sustainable iridescence of cast and shear coatings of cellulose nanocrystals.

As an eco-friendly sustainable iridescent coating, cholesteric cellulose nanocrystal (CNC) is susceptible to substrate effects or shearing effects. In this work, interface interaction and liquid crystal phase transition were evaluated for fabricating iridescent cast or shear coatings of CNCs onto substrates of polystyrene, glass, ceramic, wood, stainless steel, metal, or metal alloy. Three types of substrate effects and four categories of shearing effects on the structure color mechanism of CNC coatings were proposed. Practically, several efficient approaches, such as increasing colloidal concentration, enhancing water-retention of substrates, raising processing temperature, slowing down shearing speed, or doping functional additives were involved. Hence, a feasible strategy was provided for preparing sustainable, iridescent, stable, and industrially scalable coatings of CNCs.