ABSTRACT
New photocatalysts, Ag-AgCl/ZnO nanorods, were successfully synthesized in this study by using microwave assisted chemical precipitation and deposition-precipitation-photoreduction methods. The optimal preparation condition was determined as pH 9 in distilled water and 40min for UV light photoreduction of Ag (i.e. Ag40-AgCl/ZnO) by degradation of methyl orange. This work investigated the feasibility of using Ag40-AgCl/ZnO to degrade lignin under natural solar light and then subsequent methane production with influencing factors like solution pH, dosage of catalyst and initial lignin concentration being considered. OH radicals were found to play the most important role in the photocatalytic process, and the new prepared catalyst possessed stable photocatalytic activity after 7 cycles' utilization. During the subsequent biogasification, the degraded lignin obtained from 120min photocatalysis yielded 184ml methane and 325ml biogas for per gram of removed total organic carbon, increased by 10.9% and 23.1%, respectively compared to the control.
Subject(s)
Lignin/metabolism , Methane/metabolism , Nanotubes/chemistry , Photolysis , Silver/chemistry , Sunlight , Zinc Oxide/chemistry , Azo Compounds/chemistry , Catalysis , Fermentation/radiation effects , Lignin/radiation effects , Pilot Projects , Silver Compounds/chemistry , Ultraviolet RaysABSTRACT
The effect of algae growth on aerobic granulation and nutrients removal was studied in two identical sequencing batch reactors (SBRs). Sunlight exposure promoted the growth of algae in the SBR (Rs), forming an algal-bacterial symbiosis in aerobic granules. Compared to the control SBR (Rc), Rs had a slower granulation process with granules of loose structure and smaller particle size. Moreover, the specific oxygen uptake rate was significantly decreased for the granules from Rs with secretion of 25.7% and 22.5% less proteins and polysaccharides respectively in the extracellular polymeric substances. Although little impact was observed on chemical oxygen demand (COD) removal, algal-bacterial symbiosis deteriorated N and P removals, about 40.7-45.4% of total N and 44% of total P in Rs in contrast to 52.9-58.3% of TN and 90% of TP in Rc, respectively. In addition, the growth of algae altered the microbial community in Rs, especially unfavorable for Nitrospiraceae and Nitrosomonadaceae.
Subject(s)
Batch Cell Culture Techniques/instrumentation , Bioreactors , Eukaryota/growth & development , Nitrogen/isolation & purification , Phosphorus/isolation & purification , Sewage , Aerobiosis , Bacteria/metabolism , Biodegradation, Environmental , Biodiversity , Biological Oxygen Demand Analysis , Biopolymers/analysis , Eukaryota/metabolism , Extracellular Space/chemistry , Oxygen/metabolism , WastewaterABSTRACT
The synthesis of SBA-15 with or without ethanol using a one-step method and its porosity were investigated. Well-ordered SBA-15 with a rod like morphology could be obtained from starting mixtures by aging at a low (60 degrees C) or high (80 degrees C) temperature in the presence of an appropriate amount of ethanol. By contrast, mesoporous materials containing aggregates of particles obtained in the absence of ethanol at high aging temperatures (70 or 80 degrees C) had complex poorly ordered structures, indicating that ethanol can affect the structure of mesoporous materials. In addition, the poorly ordered mesoporous materials had unusual desorption characteristics, namely they possessed a two-step desorption branch.
Subject(s)
Crystallization/methods , Nanostructures/chemistry , Nanostructures/ultrastructure , Silicon Dioxide/chemical synthesis , Macromolecular Substances/chemistry , Materials Testing , Molecular Conformation , Nanotechnology/methods , Particle Size , Surface PropertiesABSTRACT
The presence of the heterogeneous mesoporous Al-MCM-41 catalyst remarkably accelerated the cyanosilylation of various aldehydes and ketones with trialkylsilyl cyanide, giving the corresponding cyanohydrin silyl ethers in quantitative yields under mild reaction conditions.
