Good Removal Effect Research Articles

Enhanced removal of antimony in dyeing wastewater by mixing Fe3 O4 with manganese sand filter material.

Wastewaters from the printing and dyeing industries contain many contaminants in particular antimony (Sb) that end up in the environment. Both manganese sand filter and Fe3 O4 have good removal effect on Sb, and are cheap and easy to obtain. We made a filter material by mechanically mixing the manganese sand filter material and ferro-ferric oxide (Fe3 O4 ). The Fe-Mn oxide filter material was analyzed by X-ray diffraction. We studied the filtration of real wastewater from a dyeing wastewater resource recovery facility in Suzhou, China, containing Sb at high concentration of 410μg/L, using dynamic tests in adsorption columns during 7days. We tested the effects of filter material volume filling ratio, the empty bed contact time (EBCT), pH, and back washing on the removal of Sb. Results show that the addition of Fe3 O4 enhanced the removal of Sb, reaching 85% of initial Sb. When the initial influent pH of the raw water is 3.0, the volume filling ratio of filter material is 60%, the EBCT is 20min, and the developed dynamic Fe-Mn oxide filter has the best removal effect on Sb. Daily back washing of the filter keeps a Sb removal rate of about 80%. PRACTITIONER POINTS: A novel and cheap Fe-Mn oxide was developed for Sb removal from dyeing wastewater. A self-designed filter device was designed to verify performance of the low-cost material. Optimal design and operational parameters of the filtration process were determined.

Effects of acid solution of different components on the pore structure and mechanical properties of coal

To explore the influence of acid solution with different components on the pore structure and mechanical properties of coal, nuclear magnetic resonance (NMR), scanning electron microscope (SEM), energy dispersion spectrum (EDS) and uniaxial compression experiments were used to analyze the acid-treated coal samples. The results show that acid treatment can obviously improve the connectivity of coal, increase the porosity of coal, and is conducive to the circulation and diffusion of gas, but the promotion effect of acid solutions of different components on pores with different pore sizes is different. After acid treatment, the number of mineral particles on the surface of the coal samples are obviously reduced, and the space filled with mineral particles is gradually exposed, thus increasing the density of pores and fractures of the coal samples. The energy spectrum analysis shows that acid solution added HF has a good removal effect on kaolinite minerals, iron minerals and calcite minerals. For the mechanical properties of the coal samples, acid treatment can reduce the strength and elastic modulus of coal samples, but increase its toughness. In addition, the fracture evolution of the acid-treated coal samples mainly goes through four stages: initial stage, transition stage, expansion stage and destruction stage. Because most of the energy accumulated in the acid-treated coal samples is used to damage the coal body, the acid-treated coal samples are easy to form fracture network, and is mostly broken in blocks when unstable.

Synthesis, Characterization, Self-Assembly, and Irritation Studies of Polyglyceryl-10 Caprylates.

1,4-dioxane should be less than or equal to 10 ppm in finished cosmetic products according to the recommendation of the Scientific Committee on Consumer Safety, but it is often generated as a by-product during the manufacturing process of poly(ethylene glycol) (PEG)-based derivatives. In order to avoid the possible risk caused by 1,4-dioxane, it might be a good choice for preparing cosmetic ingredients by using polyglycerin (PG) instead of PEG as a hydrophilic segment. In the present study, polyglyceryl-10 caprylates were synthesized by the esterification reaction between polyglycerin-10 and caprylic acid. FTIR and 1H NMR were utilized to confirm the chemical structures of the obtained polyglyceryl-10 caprylates. Light transmittance was availed to investigate the water solubility of polyglyceryl-10 caprylates. The self-assembly behavior, size, and size distribution of polyglyceryl-10 caprylates were investigated by dynamic light scattering. The makeup cleansing effect was also evaluated by in vitro and in vivo methods. Irritation was evaluated by hen’s egg test-chorioallantoic membrane assay (HET-CAM). Results showed that polyglyceryl-10 monocaprylate could self-assemble into nanoparticles in the water at the concentration range of 2.5–10 wt% with a transparent appearance. The diameter of formed nanoparticles was around 100 nm with a narrow particle size distribution around 0.1 at the concentration of 2.5 wt% or 5 wt%. Polyglyceryl-10 monocaprylate exhibited good removal effect against makeup and excellent removal efficacy against pen eyeliner. The irritation of polyglyceryl-10 monocaprylate evaluated by HET-CAM at the concentration of 4 wt% was moderate irritant (irritation score = 8.4), which was lower than that of PEG-6 caprylic/capric glycerides (severe irritant, irritation score = 14.1). Therefore, polyglyceryl-10 monocaprylate might be a promising cosmetic ingredient for transparent makeup removing water.

Practical application of domestic sewage in a new compound biological filter

The application of a new composite biofilter with a batch-type mud membrane composite biofilter (CSBF) series deep treatment filter (EBF) combination in urban domestic sewage was studied. The results of 20-day operation data show that the new filter process has good removal effect on COD, NH3-N, TN and TP. The average removal rate of COD during operation is 94.63%, the average removal rate of NH3-N is 99.02%, and the average removal rate of TN is 77.89%. The average removal rate of TP is 97.99%, and each index is stable to the first-class A standard of GB8978-1996, in which COD, NH3-N and TP can reach the surface water class IV standard.

Organic and nutrient removal during start-up period for domestic sewage treatment by an A/O mixed carrier system

This study combined biofilm method and A/O process reasonably to form the biological treatment system. This experiment focused on the performance of the system for domestic sewage according to the determination of CODCr, ammonia nitrogen, total nitrogen, and total phosphorus. The A/O-mixed carrier system had a good removal effect on organic pollutants for simulated domestic sewage. At the start-up period, the average removal rates of CODCr, ammonia nitrogen and total nitrogen were 92%, 90% and 55%, respectively. But the removal effect of total phosphorus was not ideal.

Abiotic reduction of p-chloronitrobenzene by sulfate green rust: influence factors, products and mechanism.

The reduction of p-chloronitrobenzene (p-CNB) by sulfate green rust (GRSO4) was systematically studied. The results revealed that GRSO4 has a good removal effect on p-CNB. The removal efficiencies of p-CNB by GRSO4 improved with the increase of the pH value. The removal efficiencies in the presence of ions were better than that of GRSO4 alone, while natural organic matter (NOM) could adsorb p-CNB, which competed with GRSO4. The reductions of p-CNB by GRSO4 under different conditions followed pseudo-first-order reaction kinetics except for the reactions in the presence of NOM. p-CNB was converted into p-chloroaniline (p-CAN), which produced p-nitrosochlorobenzene and p-chlorophenylhydroxylamine as the intermediate products. The results of the X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed GRSO4 was gradually transformed into goethite. Fe(ii) in the GRSO4 structure was the main electron donor involved in the reaction.

Catalytic degradation of Acid Orange 7 in water by persulfate activated with CuFe2O4@RSDBC

In this study, a novel series of rectorite/sludge derived biochar (RSDBC) supporting CuFe2O4 (CuFe2O4@RSDBC) composites were prepared as an effective catalyst to active persulfate (PS) for the removal of Acid Orange 7 (AO7) in water. The character of catalyst was analyzed by scanning electron microscope (SEM), transmission electron microscopy (TEM), fourier transform infrared spectroscopy (FTIR) and x-ray diffraction (XRD). Various influencing factors including initial pH, PS concentration, catalyst dosage, initial dye concentration and reaction temperature were investigated. The optimal reaction conditions were found to be: PS concentration 2 mM; catalyst dosage 0.6 g l−1; initial pH value 7.0 and 25 °C of reaction temperature. Further radical quenching tests were performed by using ethanol, tert-butanol (TBA) and benzoquinone (BQ), which confirmed that sulfate radicals () and hydroxyl radicals (HO•−) were the reactive species in the degradation process. The Gas chromatography-mass spectrometry (GC-MS) analysis was employed to determine the intermediate products and a plausible degradation pathway is proposed. In addition, the CuFe2O4@RSDBC sample exhibited high color removal ability (95%) and stable performance after three successive runs. At last, the catalyst proved a good removal effect for actual dye wastewater. These results indicate that CuFe2O4@RSDBC hybrids could be as effective catalysts for PS activation on dye pollutants elimination.

Preparation of Chitosan/NiFe-Layered Double Hydroxides Composites and Its Fenton-Like Catalytic Oxidation of Phenolic Compounds

In this study, chitosan-based Ni–Fe hydrotalcite composites (CS/NiFe-LDHs) and Ni–Fe hydrotalcite (NiFe-LDHs) were prepared by low-saturation coprecipitation method to investigate their oxidation and catalytic properties for phenolic compounds. The materials were characterized by TEM, XRD, FTIR, SEM, and TG–DTG, which proved that chitosan (CS) was successfully introduced into hydrotalcite forming CS/LDHs, which still had the structural characteristics of hydrotalcite. The oxidation effect and catalytic oxidation effect of CS/NiFe-LDHs on phenolic compounds were investigated. The results showed that under the optimal conditions, the oxidation efficiency on phenolic compounds (BPA, 2,4-DCP, and phenol) was 62.25%, 70.02%, and 42.13%, respectively, and the removal efficiency was 94.8%, 93.71%, and 98.98% by heterogeneous Fenton-like catalytic oxidation. CS/NiFe-LDHs as a catalyst has a good removal effect on phenolic compounds, and no sludge is produced, the range of pH value is broadened in the reaction (3–12). It can be easily recycled for five subsequent runs and has a good application prospect.

Molecular Dynamics Evaluation of Removal of Acid Gases from SNG by Ionic Liquid

A process for removing acid gas from synthetic natural gas based on ionic liquids (ILs) at room temperature is proposed. The structural properties, such as the radial and special distribution functions, and the dynamic properties, such as the self-diffusivity, are computed by molecular dynamics simulation methods. The microscopic characteristics are related to the macroscopic properties. The effects of different alkyl chain lengths and anionic ILs on the absorption process are studied. The ILs are proven to have good adsorption effects on acid gases, and the optimum IL, namely, [bmim][Tf2N], is determined. The structure–property relationships between the ILs and the dissolution diffusion are the basis for designing novel ILs. The design process is simulated by Aspen Plus. The results show that the process has good removal effects and that three key stream concentrations are increased compared with those based on a traditional solvent process. The capture rate of CO2 is 97.6%, the removal rate of H2S is 94...

Effect of plastic carbon fiber-biofilm technology on landscape water purification

In this study, a new type of plastic carbon fiber filler was applied to biofilm technology. The optimum purification conditions for eutrophic landscape water were discussed by controlling the filling amount, aeration volume and pollutant concentration. The activated sludge from the sewage treatment plant is used for aeration and filming to explore the effect of the filler on the purification effect of the landscape water body. Studies have shown that the composite filler has a good removal effect on CODcr, TN and TP in eutrophic water, and is a highly efficient new water treatment material.

Process and development of ozone-biological activated carbon treatment for micro-polluted raw water

The basic principle and process flow of ozone-biological activated carbon treatment of micro-polluted source water were analyzed, and the application of the method at home and abroad was introduced. Some problems that need to be paid attention to when applying the method were put forward. The results show that ozone-activated carbon water purification technology can effectively remove organic matter and ammonia nitrogen in water. It also has good removal effect on inorganic reducing substances, chroma and turbidity in water. Moreover, the mutagenic activity of effluent can be effectively reduced to ensure the safety of drinking water. Some problems which should be attended are prompted when this technique is in application in the paper. It is a water purification technology worth promoting.

Morphology investigation of sectional stripes and adhering slag based on vapor-to-melt ratio in Nd:YAG laser cutting of Al2O3 ceramics

A morphology investigation of sectional stripes and adhering slag based on the vapor-to-melt ratio is carried out to reveal the effect of material removal proportion on the Nd:YAG laser cutting process. The influences of vapor-to-melt ratio on the morphology of sectional stripes and adhering slag (roughness, stripe width, and slag height) are investigated by the experimental observation and analysis. It is shown that the maximum particle diameter demonstrates the size of the hanging slag nodules, and the average particle diameter reflects the section stripe spacing. At a suitable vapor-to-melt ratio, the stripes with regular morphology and uniform width allow the molten layer to produce spherical particles with smaller diameter and uniform size. The molten pool is superimposed and the material is evenly paved, resulting in a good roughness of the section. Because of the good removal effect, the proportion of the membranous part hanging on the bottom surface is higher than that of the nodular part. Although the slag height is relatively obvious, the microcracks connected inside make the whole adhering slag easier to remove. The control of vapor-to-melt ratio is helpful for reducing the height of adhering slag and the proportion of nodular solidified materials, which has guiding significance for improving the cutting quality of the bottom surface of the plate.

Occurrence and Removal of N-nitrosamines in the Wastewater Treatment Plants Using Different Treatment Processes

This study measured the concentrations of six N-nitrosamines (NAs) in water samples from each process stage of three wastewater treatment plants (WWTPs) and their corresponding receiving rivers. The occurrence and removal of NAs was then systematically studied in three WWTPs using different treatment processes, and their pollution profiles and sources in the receiving rivers were analyzed. The results showed that the six NAs occurred widely in the wastewater from every process stage of three WWTPs. NPIP, NDMA, and NPYR were the dominant pollutants with concentrations in the tens to hundreds ng·L-1. The three WWTPs using different treatment processes removed a certain amount of NAs, and the modified A2/O and A2/O+MBR showed good NAs removal effects, with total removal rates of 95% and 63%, respectively. The removal of NAs mainly relied on microbial degradation and transformation during the biochemical stage. During the filtration, disinfection, and MBR stages, NAs precursors in the wastewater treatment system could form some added NAs after a series of reactions. The six NAs were also frequently detected in the surface waters of receiving rivers, where the main pollutants were also MDMA, NPIP, and NPYR, which was consistent with the influent of the WTTPs. The sources of NAs in the receiving rivers were wide ranging and complicated, including emission from the effluent of the WTTPs, the release of untreated sanitary sewage, industrial wastewater, and surface runoff from industrial districts. Therefore, effective measures should be taken to reduce the input of NAs into receiving rivers, such as enhancing the capacity of sewage collection and treatment and optimizing sewage treatment processes.

Comparison of the effect of double-mirror combined with gallbladder removal and laparoscopic cholecystectomy for gallbladder stones

Objective To compare the effect of double-mirror combined with gallbladder removal and laparoscopic cholecystectomy for gallstones. Methods From January 2016 to December 2017, 120 patients with gallstones in the Department of Hepatobiliary Surgery of Dongyang People's Hospital were enrolled.The patients were divided into laparoscopic group (n=60) and double-mirror group (n=60) according to the random number table method.Laparoscopic cholecystectomy was performed in the laparoscopic group, and double-mirror (laparoscopic and choledochoscopy) combined with gallstone removal was performed in the double-mirror group.The surgical results of the two procedures were analyzed.Surgical index, postoperative recovery status, postoperative complications and recurrence rate of one year after surgery were observed. Results The success rate of surgery in both two groups was 100.0%.The operation time of the double-mirror group [(48.2±5.3)min] was significantly longer than that of the laparoscopic group [(41.2±5.8)min](t=6.901, P 0.05). The total incidence rate of postoperative complications in the double-mirror group was 3.3%, which was significantly lower than 15.0% in the laparoscopic group (χ2=4.904, P=0.027). In the double-mirror group, the recurrence rate of calculi was 1.7% in 1 year after surgery, which in the laparoscopic group was 0, there was no statistically significant difference between the two groups (χ2=1.008, P=0.315). Conclusion Double-mirror combined with gallbladder stone removal and laparoscopic cholecystectomy can achieve good stone removal effect, the short-term efficacy is similar to long-term efficacy, laparoscopic cholecystectomy has shorter operation time.Double-mirror combined with gallstone removal has advantages in postoperative recovery and lower complications. Key words: Cholecystolithiasis; Biliary tract surgical procedures; Cholecystectomy, laparoscopic; Hemorrhage; Recurrence; Postoperative complications; Length of stay

Study on the structure and properties of PPS/PCNF hybrid membranes and their applications in wastewater treatment

Membrane separation technology is widely used in water treatment. In this paper, we prepared polyphenylene sulfide/porous carbon nanofibers (PPS/PCNF) hybrid membranes by adding PCNF into PPS membranes. In the thermally induced phase separation (TIPS) process, PCNF could migrate to the top surfaces of the hybrid membranes, which made the pore size on the top surfaces of the membranes significantly decreasing and the pore size distribution became narrower. Compared with the conventional surface coating modified membranes, the surface coating material of PCNF would not falling off from PPS membrane, and it made the hybrid membranes to become more hydrophobic and to have the higher breaking elongation. PCNF, as a kind of heterogeneous nucleating agent, increased the melting temperature and the crystallization temperature of PPS/PCNF membrane, which resulted in PPS/PCNF membrane having the higher breaking elongation. Most importantly, PPS/PCNF hybrid membranes had a good intercepting performance, with bovine serum protein (BSA) intercepting rate of 92.7% and dye methylene blue (MLB) intercepting rate of 99.9%. Meanwhile, they also had a good removal effect on bacteria in strong polar organic solvent, and the removal rate achieved 93.7%. Thus, the PCNF hybridized PPS can play a crucial role on wastewater treatment in the future.

Preparation of aminated chitosan microspheres by one-pot method and their adsorption properties for dye wastewater.

Polyamine chelating adsorbents have a good removal effect on dye wastewater. In this study, small molecule triethylenetetramine and macromolecular poly(ethylene imine) were selected as aminated reagent, and two kinds of aminated chitosan microspheres, TETA-CTSms and PEI-CTSms, were obtained by emulsion cross-linking method. The microspheres were fully characterized by FTIR, SEM, XRD, EDS and TGA. EDS results showed that the N content of the PEI-CTSms and TETA-CTSms microspheres increased significantly after the cross-linking reaction and can reach 5.7 wt% and 7.3 wt%, respectively. Adsorption experiments confirmed that TETA-CTSms and PEI-CTSms showed greater adsorption characteristics for anionic dye reactive yellow (RY) in aqueous solutions compared with CTSms, and the adsorption capacity per unit area was increased by 39.11% and 88.56%, respectively. The adsorption capacity of aminated microspheres for RY decreased with the increase of pH. The adsorption kinetics conformed to the pseudo-second-order model, and the adsorption process was in accordance with the Langmuir isotherm model. The negative value of ΔG confirmed that the adsorption process was spontaneous, and the dye adsorption was a multiple process dominated by chemical chelating and physical adsorption.

Stability of aerobic granular sludge in a pilot scale sequencing batch reactor enhanced by granular particle size control

Aerobic granulation was successfully achieved in a pilot scale sequencing batch reactor within 40 days. Then, stability of different particle size granules was explored according to their activity and resistance to ultrasonic crushing. Different particle size granules (0.3–0.6 mm, 0.6–1 mm, 1–1.43 mm, 1.43–2 mm, 2–3 mm and 3–4 mm) were exposed under different ultrasonic power separately. It was found that the granules with 2–3 mm always had the maximum granulation rates after ultrasonic crushing. Meanwhile, activity data showed that the 2–3 mm granules had the lowest specific oxygen utilization rates, which indicated that they were easier to maintain stability as the increase of their particle sizes was the slowest. So, 500 mL mixed liquid of the reactor were taken out and sieved to obtain the 2–3 mm granules, which were subsequently returned to the reactor to increase their proportion. Through the manual regulation, the proportion of 2–3 mm granules kept increasing which gradually became dominant in the reactor. Under the strategy of 86 days of operation, the aerobic granules were regular and compact, which had good removal effects of the real wastewater. The results indicated that the stability of the system could be greatly enhanced by the method, which provided a new strategy to maintain the granular stability.

Operation Characteristics of the Biofilm CANON Reactor During the Temperature Reduction Process

The focus of this paper, was low temperature, high ammonia nitrogen wastewater. The operation characteristics of the biofilm CANON process during the temperature reduction process were determined, by continuously adjusting different operating conditions. The aim was to explore the methods needed for the CANON process to obtain stable shortcut nitrification and a good nitrogen removal effect, when the influent NH4+-N concentration is high and the temperature low. The results showed that, ① compared with the biofilm CANON reactor temperature changing from medium to low temperature directly (30℃±1℃→19℃), it was more conducive to adapt the nitrogen-removing bacteria to the low-temperature environment, while the temperature was gradually lowered. Moreover, the extent of each reduction should be minimized. Besides, the operating conditions should be adjusted to ensure the nitrogen removal effect. ② The temperature was gradually reduced to about 19℃ after 25 d, and then decreased to about 15℃ after another 18 d. The NH4+-N and TN removal rates could be respectively stable at 90% and 70% over a long period of time. The TN removal rate and removal load could still reach 72.52% and 0.78 kg·(m3·d)-1, respectively, even when the temperature dropped to 12℃. ③ When adapting biological CANON sludge during the temperature reduction process, shortcut nitrification should be given priority. A stable shortcut nitrification effect should be obtained by maintaining a certain concentration of residual NH4+-N, and by strictly controlling the DO concentration to restrain NOB activity.

Analysis of rural domestic sewage treatment in Guizhou

Based on the data statistics and field investigation of domestic sewage treatment in 1414 township-level units and 17664 administrative villages in Guizhou Province, this paper summarizes and analyzes the coverage of administrative villages of sewage treatment facilities in Guizhou Province and the current treatment technology model. About 13.24% of the domestic sewage in administrative villages in the whole province has been centralized or partially centralized, and the degree of sewage treatment is relatively low. Among them, Zunyi and Guiyang are relatively high, with the coverage rates of 30.7% and 27.4% respectively. However, Bijie is the lowest with the largest rural population, which is 7.4%. In addition, through the investigation of rural sewage treatment technology mode in Guizhou Province, it can be concluded that in areas with relatively concentrated villages, centralized treatment technologies for rural domestic sewage are commonly adopted, including constructed wetlands and integrated sewage treatment equipment, and a decentralized sewage treatment system is often adopted for single households. In the selection of rural domestic sewage treatment technology scheme, the principles of simple process, low infrastructure cost, easy maintenance, and pollution-free and good removal effect of rural domestic sewage are taken as far as possible.

Experimental Research on Enhanced Denitrification by Biological Agents

Biological agents play a significant role in sewage treatment, with good removal effect, low sludge yield, good performance, and shorten the system start-up time, impact load resistance and stability enhancement.This paper describes the characteristics ofbiological agents and the effect of biological agents on wastewater denitrification was investigated through experiments, so as to provide effective basis support for the wide application of biological agents in the field of urban sewage treatment.The experiment showed that through reasonable addition of biological agents,the removal rates of COD,NH3-N and TNinlowpollutantsewage treatmentwere increased by 41%, 15% and 62% respectively.