Stability performance analysis of Fe based MOFs for peroxydisulfates activation to effectively degrade ciprofloxacin.

Fe-based metal-organic frameworks (MOFs) show high activity toward the activation of peroxodisulfate (PDS) for the removal of organic micropollutants (OMPs) in wastewater treatment. However, there is a phenomenon of Fe ion dissolution in the Fe-based MOFs' active PDS system, and the reasons and influencing factors that cause Fe ion dissolution are poorly understood. In this study, we synthesized four types of Fe-based MOFs and confirmed their crystal structure through characterization.

Regulating the reaction pathway of nZVI to improve the decontamination performance through magnetic spatial confinement effect.

Nanoscale zero-valent iron (nZVI) shows high effectiveness in the catalyzed removal of contaminants in wastewater treatment. However, the uncontrolled interfacial electron transfer behavior and formation of surface iron oxide (FeOx) layer led to severe electron wasting and occasionally form highly toxic intermediates. Here, we constructed magnetic mesoporous SiO shell on surface of nZVI to stimulate a magnetic spatial confinement effect and regulate the electron transfer pattern.

[Two-Stage Denitrification Process Performance with Solid Slow-Release Carbon Source].

During wastewater treatment using a traditional biological denitrification process, the excessive concentration of nitrate nitrogen (NO-N) in the effluent is the primary cause of excessive total nitrogen (TN) generation. By using an external carbon source to increase the carbon to nitrogen ratio (C/N), the denitrification process can be strengthened, which effectively addresses this problem. Using an integrated denitrification reactor developed based on the two-stage denitrification process principle with the addition of polybutylene succinate (PBS) in the second stage, the denitrification process was analyzed using a scanning electron microscope before and after characterization of PBS materials.

Online prediction of effluent COD in the anaerobic wastewater treatment system based on PCA-LSSVM algorithm.

Since anaerobic wastewater treatment is a nonlinear and complex biochemical process, reasonable monitoring and control are needed to keep it operating stably and efficiently. In this paper, a least-square support-vector machine (LS-SVM) was employed to construct models for the prediction of effluent chemical oxygen demand (COD) in an anaerobic wastewater treatment system. The result revealed that the performance of the steady-state model based on LS-SVM for predicting effluent COD was acceptable, with the maximum relative error (RE) of 11.

[Using HKUST-1 as a Template for Copper Oxides Preparation to Activate Peroxymonosulfate for RhB Degradation].

Using Cu-MOF (HKUST-1) as a template, copper oxide was prepared by heat treatment under different temperatures in this study. The effect of treatment temperature on the composition and morphology of the products were studied. The catalytic abilities of the copper oxide products were tested through a series of experiments of activating peroxymonosulfate (PMS) to degrade RhB under different conditions.

[MIL-88A@MIP Activated Persulfate for Targeted Degradation of Dibutyl Phthalate].

MIL-88A@MIP was fabricated for the first time in this experiment with a metal-organic framework of MIL-88A as the precursor based on the molecular imprinting method. It was characterized by X-ray diffraction (XRD), scanning electronic microscopy (SEM), energy dispersive spectrometer (EDS), and N adsorption. The catalytic performance of MIL-88A@MIP was tested to activate persulfate (PS) to generate SO for the degradation of dibutyl phthalate (DBP), which was used as a target pollutant.

Modeling and multi-objective optimization for ANAMMOX process under COD disturbance using hybrid intelligent algorithm.

Anaerobic ammonium oxidation (ANAMMOX) has been regarded as an efficient process to treat nitrogen-containing wastewater. However, the treatment process is not fully understood in terms of reaction mechanisms, process simulation, and control. In this paper, a multi-objective control strategy mixed soft-sensing model (MCSSM) is developed to systematically design the operating variations for multi-objective control by integrating the developed model, a least square support vector machine optimized with principal component analysis (PCA-LSSVM) and non-dominated sorting genetic algorithm-II (NSGA-II).

[Removal of Sulfate Ions from Aqueous Solution by Adsorption with Hydrotalcite- like Composite].

Hydrotalcite-like composite synthesized by co-precipitation method was used as an adsorbent to remove the sulfate ions in aqueous solution. XRD, FT-IR , SEM and EDS elemental analysis were used to clarify the structure and composition of the hydrotalcite- like composite. The influences of time, initial pH value and coexisting ions on adsorption performance were investigated.

[Effects of particle size of zero-valent iron on the reactivity of activating persulfate and kinetics for the degradation of acid orange 7].

This research described the heterogeneous reactions of persulfate with different particle sizes of zero-valent iron (including 1 mm-ZVI,150 μm-ZVI,50 nm-ZVI) for degradation of acid orange 7(AO7) , and studied the kinetics and intermediate products of AO7 under these systems. The results demonstrated that these three types of ZVI were efficient in promoting the degradation of AO7, the degradation efficiencies of AO7 were 43% , 97% , and 100% within 90 min respectively, in the 1 mm-ZVI,150 μm-ZVI and 50 nm- ZVI systems, respectively. With the results of kinetic fitting models, the pseudo first-order kinetics exhibited better fitting results in the 1 mm-ZVI,150 μm-ZVI systems, while the second-order kinetics exhibited better fitting results in the 50 nm-ZVI system.

[Effect of constructed wetland on the purification of industrial zone rainfall runoff contaminated with phenanthrene].

According to the water characteristics of industrial rainfall runoff in the catchment of Tongsha Reservoir, Dongguan City, a subsurface-flow constructed wetland (SSFCW) was used to treat simulated rainfall and the spatial variation of removal efficiency of contaminants in the wetland bed was analyzed. The longitudinal and vertical variation of removal efficiency of COD, NH4(+) -N, TN, TP and phenanthrene were examined. Enzyme activity of polyphenol oxidase (PPO) and nitrate reductase (NR) along the wetland bed were analyzed as well, meanwhile, four biogeochemical indexes of the wetland system, including DO, pH, ORP and water temperature, were monitored and their influences on the removal efficiency of contaminants and enzyme activity were analyzed.

[Mechanism of reductive dechlorination of trichlorophenol with different electron donors].

A test was conducted to examine the degradation effect and reductive dechlorination pathway of 2, 4, 6-trichlorophenol (2,4,6-TCP) in the presence of different electron donors, such as glucose, sodium lactate, sodium pyruvate and sodium acetate. The results showed that, compared with the effect of glucose, sodium lactate, sodium pyruvate and sodium acetate enhanced the dechlorination of 2, 4, 6-TCP effectively, among which sodium lactate could serve as a kind of hydrogen release compound, and the electrons required for reductive dechlorination were released in a sustained way. Substrate metabolism dehydrogenase activity was improved by the external electron donor; after reaction for 240 h, the activity of dehydrogenase was increased in the four electron donor systems, by 21.

[Influences of pH and complexing agents on degradation of reactive brilliant blue KN-R by ferrous activated persulfate].

The influences of pH and complexing agents on degradation of reactive brilliant blue KN-R by ferrous activated persulfate were investigated, and finally the complexed and the uncomplexed system were compared. Because the lower the pH the more quickly will be the dissociation of S2O8(2-) to the SO4(-*) and the ORP of the dominant radical SO4(-*) in the acidic condition is higher than the dominant radical *OH in the alkaline condition, KN-R degradation rates in acidic condition are far outweigh in the neutral and alkaline conditions. When pH value was 3, the residual rate of KN-R was 17.

[Treatment studies of industrial rainoff with a new type of constructed wetland].

According to water characteristics of industrial rain runoff in a catchment of Tongsha reservoir, Dongguan city, an improved baffled constructed wetland (BCW) was used for purification experiment study of simulated and on-the-spot rain runoff. The purification effects of simulated rain runoff were compared in different operated phases of BCW. Meanwhile, the variation of the pollutants (COD, SS, TN, TP, NH4(+) -N, Pb, Zn, Cu) along the BCW and their removal mechanism were analyzed and discussed, respectively.

[Degradation of azo dye acid orange 7(AO7) by heat, ZVI and heat/ZVI activated persulfate].

Effects of temperatures, PS concentrations and ZVI dosages on AO7 decomposition were investigated in sole heat and ZVI activating systems. The degradation results of two systems were compared for selecting a better activating way for AO7 degradation and finally the two activating ways were combined for getting the optimal AO7 degradation efficiency. The degradation of AO7 by Heat/PS systems followed pseudo first-order kinetics.

[Study on toxicity of phenol to anaerobic granular sludge].

To understand the toxicity of phenol to anaerobic granular sludge, the changes of specific methanogenic activity (SMA), extracellular polymeric substance (EPS) constituents and coenzyme F420 concentration of anaerobic granular sludge at various phenol concentrations were investigated. Meanwhile, Fourier transform infrared spectrometry was used to analyze the structure of EPS. The results show that the phenol has little effect on anaerobic granular sludge when the concentration of phenol is less than 100 mg/L.

The fate of di-n-butyl phthalate in a laboratory-scale anaerobic/anoxic/oxic wastewater treatment process.

A laboratory-scale anaerobic/anoxic/oxic (AAO) wastewater treatment system was employed to investigate the effects of hydraulic retention time (HRT) and sludge retention time (SRT) on the removal and fate of di-n-butyl phthalate (DnBP). HRT had no significant effect on DNBP removal between 12 and 30 h. However, longer HRT increased DnBP accumulation in the system and DnBP retention in the waste sludge.

Effects of hemicellulose removal on cellulose fiber structure and recycling characteristics of eucalyptus pulp.

Eucalyptus pulp fibers with large differences in cellulose and hemicellulose proportions but similar lignin contents were produced by partial removal of the hemicellulose and studied using Cross-Polarization Magic Angle Spinning Carbon-13 Nuclear Magnetic Resonance (CP/MAS (13)C NMR) in combination with spectral fitting, Atomic Force Microscopy (AFM), X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR). There were remarkable differences in both cellulose fibril structure, pore structure and cellulose supermolecular structure between the samples. CP/MAS (13)C NMR combined with spectral fitting demonstrated an increase in average fibril aggregate size (17.

A fast predicting neural fuzzy model for on-line estimation of nutrient dynamics in an anoxic/oxic process.

In this paper a software sensor based on a fuzzy neural network approach was proposed for real-time estimation of nutrient concentrations. In order to improve the network performance, fuzzy subtractive clustering was used to identify model architecture, extract and optimize fuzzy rule of the model. A split network structure was applied separately for anaerobic and aerobic conditions was employed with dynamic modeling methods such as autoregressive with exogenous inputs and multi-way principal component analysis (MPCA).