[Preparation and Application of Magnetic Water Treatment Materials Based on Iron Sludge].

In recent years, solid waste iron sludge (red mud, iron-containing water treatment residues, and iron-rich sludge) has been widely used to remove pollutants in the water environment; however, the difficulty of separating powdered iron sludge from the water environment media makes it impossible to apply it as a water treatment material on a large scale, and preparing iron sludge into magnetic materials that are easy to be separated is one of the effective strategies to solve this bottleneck. According to the existing research on iron sludge-based magnetic materials at home and abroad, the preparation methods of magnetic materials using iron sludge as raw materials are summarized, including a series of methods, including the thermal decomposition method, hydrothermal and solvothermal method, co-precipitation method, reduction roasting method, and carbonization method. Additionally, it is pointed out that the currently commonly used preparation methods are thermal decomposition, hydrothermal and solvothermal, and co-precipitation. In addition, the performance and application of these magnetic materials as adsorbents or catalysts in water treatment are also summarized. In general, iron sludge-based magnetic materials can better absorb heavy metals and organic pollutants in water. The main adsorption mechanisms are complexation, electrostatic interaction, reduction, cation exchange, and precipitation. As a catalyst, it can efficiently oxidize and degrade organic pollutants by generating strong oxidizing substances:SO4-· and ·OH. Although there have been many studies on the preparation and application of iron sludge-based magnetic materials, because the raw material iron sludge contains many impurities, the magnetic materials prepared from iron sludge also have certain impurities. Therefore, it is still necessary to strengthen the research on the safety of iron sludge-based magnetic materials in the future to further ensure that they can be used as environmentally friendly materials for water environment restoration.

[Removal Efficiency and Mechanism of Ammonia Nitrogen in a Low Temperature Groundwater Purification Process].

To explore the mechanism and efficiency of ammonia nitrogen removal, a pilot-scale biofilter for the simultaneous removal of high concentrations of iron, manganese, and ammonia nitrogen[Fe(Ⅱ) 11.9-14.8 mg·L-1, Mn(Ⅱ) 1.1-1.5mg·L-1, and NH4+-N 1.1-3.2 mg·L-1] from low temperature(5-6℃) groundwater was operated in a water supply plant in Northeast China. Results indicated excellent performance for ammonia nitrogen removal during the initial start-up stage. According to theoretical analysis and experimental verification, TNloss was driven by the adsorption of ammonia nitrogen by iron oxides, and the conversion of ammonia nitrogen into nitrate nitrogen occurred via biological nitrification. When the concentration of ammonia nitrogen increased, due to limited adsorption sites, the adsorption capacity of iron oxides remained stable at approximately 1 mg·L-1. For the same period, the amount of ammonia nitrogen removal via oxidation continued to increase, with higher quantities removed in the upper filter layer than in the lower filter layer. Dissolved oxygen(DO) is the limiting factor in the further increase in the removal of ammonia nitrogen by oxidation. With an increase in the filtration rate, the adsorption time of ammonia nitrogen by iron oxides was shortened, and the adsorption amount was reduced. Meanwhile, the shortening of EBCT reduced the ammonia nitrogen removed by nitrification under the action of nitrifying bacteria in the unit volume of the filter material. Based on these findings, it is recommended that the thickness of the filter layer should be increased to improve ammonia nitrogen removal performance.

Predictive Indicators for Necrotizing Enterocolitis With the Presence of Portal Venous Gas and Outcomes of Surgical Interventions.

Objectives: Portal venous gas (PVG) was an important clinical sign in stage II or III necrotizing enterocolitis (NEC) in preterm neonates. Not a proper predictive indicator was found to predict the diseases (NEC with the presence of PVG) up to now. There is a need to put forward predictive indicators and compare the predictive effects among them. Methods: We conducted a retrospective study of preterm neonates with NEC-PVG (n = 61) or NEC-non PVG (n = 62) from 2014 to 2021. Predictive indicators were put forward and determined by receiver operating characteristic curve analysis. An analysis of the surgical interventions and their outcomes was performed. Results: The incidence rate of NEC among preterm neonates was 4.99%; surgical and conservative interventions accounted for 20.47 and 75.07%, and the mortality rate was 0.03%. The composition ratio of shock in the NEC-PVG group increased 13.2% (P = 0.029). C-reactive protein, fibrinogen degradation product, and blood glucose had better predictive effects in the predictive indicators (P < 0.05). Intestinal necrosis and subependymal hemorrhage in the outcomes of surgical interventions had a strong relationship with the presence of PVG in NEC II/III (P < 0.05). Conclusion: Early and reasonable use of antibiotics, improvement of coagulation function, rectification of acidosis, and decreased blood glucose could cut down the occurrence of the disease (NEC with the presence of PVG). Except for subependymal hemorrhage and intestinal necrosis, NEC with the presence of PVG did not increase the occurrence of other outcomes after surgery.

[Preparation and Comparison of Arsenic Removal Granular Adsorbent Based on Iron-Manganese Sludge].

Backwashing sludge is an efficient adsorbent for arsenic removal. However, considering the practical application, it is unfavorable for solid-liquid separation. To overcome this disadvantage, a high-temperature baking method was used to prepare a granular adsorbent (GA) with iron-manganese sludge, along with an embedding method with drying (H-GA) and lyophilization (D-GA). The characterization results showed that the surface of the three adsorbents were rough, with specific surface areas of 43.830, 110.30, and 129.18 m2·g-1, respectively. The adsorption experiments showed that the adsorption of arsenic by H-GA and D-GA was much higher than that of GA. The maximum adsorption capacities of GA, H-GA, and D-GA were 5.05, 14.95, and 13.45 mg·g-1, respectively. The Langmuir model fit the adsorption process of arsenic by H-GA and D-GA better, whereas the Freundlich model fit the adsorption process of GA better. The Pseudo-first order model and Pseudo-second order model were suitable to describe the kinetic curves of the three adsorbents. The acidic environment was more conducive to the adsorption of arsenic. The particle adsorbents prepared by the embedding method, H-GA and D-GA, retained the original structure of iron-manganese sludge, and the specific surface area was much larger than that of GA; thus, the adsorption capacity was greater than that of GA. Drying and lyophilization had no significant effect on the adsorption performance of granular adsorbents prepared by embedding.

[Arsenic(â ¤) Removal by Granular Adsorbents Made from Backwashing Residuals from Biofilters for Iron and Manganese Removal].

Granular adsorbents for arsenic removal (GA) made from the backwashing residuals from iron and manganese removal biofilters for groundwater were characterized and examined as an arsenate sorbent. The GA were characterized by SEM-EDS microscopy, X-ray diffraction (XRD), and BET surface area measurement. The results showed that the GA had rough surfaces, developed pores, and were mainly amorphous, with small fractions of crystalline quartz and hematite. The surface area of the GA, which consists of many mesopores, was 43.8 m2·g-1. The kinetic studies revealed that arsenate adsorption on the GA was described by a pseudo-second-order kinetic equation, and the Freundlich isotherm equation fit the arsenate adsorption well (R2=0.994). The maximum adsorption capacity calculated by the Langmuir isotherm equation for As(Ⅴ) was 5.05 mg·g-1. Further studies showed that the GA operated well for As(Ⅴ) removal over a broad range in pH from 1.1 to 9.5. The coexistence of HCO3- and SO42- had no great influence on arsenic adsorption, while the H2PO4- and SiO32- showed negative effects. The GA can be regenerated well, and 82% of the original adsorption capacity was maintained after three regeneration cycles.

[Removal of High Concentration of Iron, Manganese and Ammonia Nitrogen from Low Temperature Groundwater Using Single Bio-filter].

A pilot-scale bio-filter was constructed for the removal of high concentrations of iron (TFe 9.0-12.0 mg·L-1, Fe(Ⅱ) 6.5-8.0 mg·L-1), manganese (1.9-2.1 mg·L-1), and ammonia nitrogen (1.4-1.7 mg·L-1) simultaneously from low temperature (5-6℃) groundwater in a plant. The results showed that iron was removed at the beginning of the bio-filter start-up, and manganese and ammonia nitrogen were removed on day 72 and day 75, respectively. The start-up period was influenced by the culture temperature and the raw water quality. For higher filtration rates, the removal of manganese was lower. When the filtration rate was more than 1.0 m·h-1, the maximum removal of manganese was about 3.0 mg·L-1. Manganese was the limiting factor for the increase of filtration rate, and the maximum filtration rate of the single bio-filter was 4.5 m·h-1. When the filtration rate was less than 6.0 m·h-1, the removal of ammonia nitrogen was about 1.5 mg·L-1, which was not affected by the filtration rate. Dissolved oxygen (DO) deficiency led to failure with the removal of more ammonia nitrogen. The required thickness of the bio-filter required for purification increased as the concentration of manganese and ammonia nitrogen increased when DO was sufficient. The removed iron, manganese, and ammonia nitrogen move to the depth of the filter layer, and there will be "manganese dissolution" when the filtration rate is increased. Iron and ammonia nitrogen in the filter layer can be oxidized and removed simultaneously. Manganese is oxidized and removed after the iron and ammonia nitrogen. The effective oxidation and removal section of manganese, iron, and ammonia nitrogen are obviously graded.

Association of OPG gene polymorphism with susceptibility to rheumatoid arthrits in Chinese Han.

AIM: To investigate the association of osteoproterin (OPG) gene polymorphisms 163A/G (rs3102735), 245T/G (rs3134069) with susceptibility to rheumatoid arthritis (RA) in Chinese Han population. OBJECTIVE: To study the correlation between the disease of rheumatoid arthritis (RA) in Chinese Han group and the association of osteoproterin (OPG) gene polymorphisms 163A/G(rs3102735) and 245T/G (rs3134069). Approaches: 205 RA patients and 171 healthy control subjects were participated into this study. Genotype analysis was conducted by polymerase chain reaction-based restriction fragment length polymorphism and was subsequently confirmed by DNA sequencing. Odd ration (OR) and 95% confidence intervals (95% CI) were calculated for the risk of genotype and allele. CONSEQUENCES: OPG gene polymorphisms 163A/G, 245T/G conformed to the Hardy-Weinberg equilibrium. The statistical differences in genotype of AA, AG, GG at 163A/G locus were founded in RA and controls. The G allele was associated with an increased risk of RA, with OR 1.219 (95% CI: 1.066-2.339). According to the observation, there are no significant differences between the RA and control groups with respect to genotype and allele frequencies of OPG gene 245T/G (χ(2)=0.734, 0.518, p>0.05). CONCLUSION: The OPG gene 163A/G SNP may be associated with the susceptibility of RA, G allele may be the risk factor for the development of RA.

[Assessment of the effect of influent NH+4-N concentration on the abundance and community structure of functional bacteria in CANON process].

To investigate macroscopic performance and microcosmic ecosystem of CANON process in low ammonium concentration at room temprature, a steady-operation CANON reactor was achieved in different ammonium concentrations by adjusting aeration and hydraulic retention time (HRT), and the effect of ammonium concentration on the abundance and community structure of functional bacteria was analyzed using PCR-DGGE and real-time PCR. The results indicated a high TN removal loading of over 1.0 g.(L.d)-1 in relatively high ammonium which was significantly reduced with the ammonium concentration of 100 mg.L-1. The community structure of ammonium oxidizing bacteria (AOB) changed sharply with the decrease of ammonium concentraion, which was not the same as anaerobic ammonium oxidizing bacteria (ANAMMOX bacteria). Besides, the abundance of the two functional groups of bacteria reduced while the population of nitrite oxidizing bacteria (NOB) rose with the decrease of ammonium, which might be the main reason for the reduction of nitrogen removal efficiency. Consequently, some strategies are needed to reduce the loss of AOB and ANAMMOX bacteria and inhibit the growth of NOB so as to maintain the nitrogen removal performance in low ammonium concentration.

Microbial characteristics of a CANON reactor during the start-up period seeding conventional activated sludge.

An up-flow oxygen-controlled biofilm reactor filled with volcanic filter was used for a completely autotrophic nitrogen-removal over nitrite (CANON) process. The reactor was successfully established by seeding conventional activated sludge at ambient temperature without additional biomass inoculation. An average total nitrogen (TN) removal rate of 1.1 kg·(m(3) d)(-1) was achieved after 180 days' operation. The bacterial morphology, community structure and spatial distribution of nitrogen removal microorganisms were analyzed by using some molecular biotechniques. Denaturant gel gradient electrophoresis (DGGE) profiles showed a distinct community shift of nitrite oxidizing bacteria (NOB) during the start-up period, which was not the same as that of aerobic ammonium-oxidizing bacteria (AerAOB) or anaerobic ammonium-oxidizing bacteria (AnAOB). Phylogenetic results indicated the predominance of Nitrosomonas, 'Candidatus Brocadia fulgida' and Nitrobacter for nitrogen removal in the system, all of which coexisted without a distinguishable niche on the biofilm.