Effect of Cu-based metal organic framework (Cu-MOF) loaded with TiO2 on the photocatalytic degradation of rhodamine B dye

Environmental Science and Pollution Research - Using copper nitrate trihydrate as the copper source, TiO2@Cu-MOF nanocomposites were prepared by a one-step crystallization method, and the effect of...     

Effect of temperature on anoxic metabolism of nitrites to nitrous oxide by polyphosphate accumulating organisms

Temperature is an important physical factor, which strongly influences biomass and metabolic activity. In this study, the effects of temperature on the anoxic metabolism of nitrite(NO-2) to nitrous oxide(N2O) by polyphosphate accumulating organisms, and the process of the accumulation of N2O(during nitrite reduction), which acts as an electron acceptor, were investigated using 91% ± 4% Candidatus Accumulibacter phosphatis sludge. The results showed that N2O is accumulated when Accumulibacter first utilize nitrite instead of oxygen as the sole electron acceptor during the denitrifying phosphorus removal process. Properties such as nitrite reduction rate, phosphorus uptake rate, N2O reduction rate, and polyhydroxyalkanoate degradation rate were all influenced by temperature variation(over the range from 10 to 30°C reaching maximum values at 25°C). The reduction rate of N2O by N2O reductase was more sensitive to temperature when N2O was utilized as the sole electron acceptor instead of NO2, and the N2O reduction rates, ranging from 0.48 to 3.53 N2O-N/(hr·g VSS), increased to 1.45 to 8.60 mg N2O-N/(hr·g VSS). The kinetics processes for temperature variation of 10 to 30°C were(θ1 = 1.140–1.216 and θ2= 1.139–1.167). In the range of 10°C to 30°C, almost all of the anoxic stoichiometry was sensitive to temperature changes. In addition, a rise in N2O reduction activity leading to a decrease in N2O accumulation in long term operations at the optimal temperature(27°C calculated by the Arrhenius model).     

邻苯二甲酸酯降解技术研究进展

邻苯二甲酸酯（Phthalate Esters,PAEs）是一类广泛使用的化学品,主要用于聚氯乙烯的增塑荆,PAEs具有雌激素效应,其降解处理十分重要。文章回顾了邻苯二甲酸酯生物降解法、吸附法和高级氧化法的有关研究,着重讨论了PAEs的化学氧化、催化氧化、光化学氧化、光化学催化氧化技术等高级氧化技术。其中光化学催化氧化技术作为一种要求的反应条件温和、降解效果理想的绿色环保技术,值得进一步研究开发。最后展望了PAEs降解技术的研究趋势。     

Research progress and prospects of complete ammonia oxidizing bacteria in wastewater treatment

• Comammox bacteria have unique physiological characteristics. • Comammox bacteria are widely distributed in natural and artificial systems. • Comammox bacteria have the potential to reduce N₂O emissions. • Coupling comammox bacteria with DEAMOX can be promoted in wastewater treatment. • Comammox bacteria have significant potential for enhancing total nitrogen removal. Complete ammonia oxidizing bacteria, or comammox bacteria (CAOB), can oxidize ammonium to nitrate on its own. Its discovery revolutionized our understanding of biological nitrification, and its distribution in both natural and artificial systems has enabled a reevaluation of the relative contribution of microorganisms to the nitrogen cycle. Its wide distribution, adaptation to oligotrophic medium, and diverse metabolic pathways, means extensive research on CAOB and its application in water treatment can be promoted. Furthermore, the energy-saving characteristics of high oxygen affinity and low sludge production may also become frontier directions for wastewater treatment. This paper provides an overview of the discovery and environmental distribution of CAOB, as well as the physiological characteristics of the microorganisms, such as nutrient medium, environmental factors, enzymes, and metabolism, focusing on future research and the application of CAOB in wastewater treatment. Further research should be carried out on the physiological characteristics of CAOB, to analyze its ecological niche and impact factors, and explore its application potential in wastewater treatment nitrogen cycle improvement.     

Toughness Enhancement of Poly(lactic acid), Bamboo Particle and Ultrafine Bamboo-Char Ternary Biocomposites by Polyethylene Glycol Plasticization

Journal of Polymers and the Environment - In this study, polyethylene glycol (PEG) was introduced into PLA/BP/UFBC ternary biocomposites as a plasticizer to improve the toughness of the...     

Electrokinetic enhancement removal of heavy metals from industrial wastewater sludge

An enhanced electrokinetic process for removal of metals (Cr, Cu, Fe, Ni, Pb, Zn) from an industrial wastewater sludge was performed. The electrokinetic experiments were conducted under a constant potential gradient (1.25 V cm(-1)) with processing fluids of tap water (TW), sodium dodecylsulfate (SDS) and citric acid (CA) for 5 days. Results showed that metal removal efficiency of heavy metals for EK-TW, EK-SDS and EK-CA systems are 11.2-60.0%, 37.2-76.5%, and 43.4-78.0%, respectively. A highest metal removal performance was found in EK-CA system. The removal priority of investigated metals from sludge by EK process was found as: Cu > Pb > Ni > Fe > Zn > Cr. The results of sequential extraction analysis revealed that the binding forms of heavy metals with sludge after electrokinetic process were highly depend upon the processing fluid operated. It was found that the binding forms of metals with sludge were changed from the more difficult extraction type (residual and sulfate fractions) to easier extraction types (exchangeable, sorbed, and organic fraction) after treatment by electrokinetic process. Results imply that if a proper treatment technology is followed by this EK process to remove metals more effectively, this treated sludge will be more beneficial for sludge utilization afterwards. Before it was reused, the risk associated with metals of more mobile forms to the environment need to be further investigated. The cost analysis was also evaluated for the investigated electrokinetic systems.