Amount Of NH Research Articles

Key role of NH4+-N in the removal of oxacillin during managed aquifer recharge: Reconsidering the recharge limitation

Frequent occurrence of trace antibiotics in reclaimed water is concerning, which inevitably causes aquifer contamination in the case of managed aquifer recharge (MAR). Global governments have formulated strict reclaimed water standards to ensure the safety of water reuse. Recent studies have found that improved antibiotics removal is intimately associated with high ammonia-oxidizing activity. However, the role of NH4+-N in the removal of residual antibiotics of reclaimed water during MAR remains unknown. NH4+-N removal and the effects of ammonia oxidation on antibiotics biodegradation in the aquifer are the most significant facts for solving the above collision. In this work, the effects of NH4+-N (0, 1 and 5 mg/L) in a model refractory antibiotic (oxacillin (OXA), 100 μg/L) attenuation were deciphered by employing three individual simulated MAR columns, which so called N0, N1 and N5. The results showed that 5 mg/L NH4+-N in influent upregulated the abundance of amo genes by 28.9 %-68.0 % in N5. And the enriched functional genes encoding key degradation enzymes enhanced the OXA removal by 18.7 % and alleviated the oxidative stress caused by antibiotics. Subsequently, antibiotic resistance genes (ARGs), mobile gene elements (MGEs) and human bacterial pathogens (HBPs) abundance were all significantly decreased. Moreover, the intimate association between ammonia-oxidizing microorganisms (AOM) and candidate OXA degraders based on microbial network analysis further supported the significance of AOM on OXA biodegradation. This study provides comprehensive evidence that appropriate amounts of NH4+-N are beneficial in antibiotics and antibiotic resistance risk reduction, providing compelling insights for refine NH4+-N recharge limitation.

Recovering ammonium from real treated wastewater by zeolite packed columns: The effect of flow rate and particle diameter

Nitrogen (N) recovery from wastewater is a desirable way to create a (N) neutral society in view of a circular economy approach. Nitrogen recovery from wastewater by employing adsorption columns filled with zeolite can be a very attractive solution. This study assessed the effect of influent flow rates (namely, 1.6 and 2.3 L h−1) and particle diameters (namely, 0.5–1.0 and 2.0–5.0 mm) of zeolite packed in columns on recovering NH4+ from real domestic treated wastewater (RDTWW). Findings revealed that maximum NH4+ recovery can be achieved by using zeolite with the smallest particle diameter (0.5–1.0 mm) and the highest influent flow rate (2.3 L h-1). The maximum NH4+ adsorption rate was 1.2, 21 and 9.8 mg NH4+ kg-1 h-1 after 205, 32 and 35 h of operation. NH4+ adsorption data were analysed by fitting them to both pseudo-first and pseudo-second order kinetic models. The former model best approximated NH4+ adsorption data. Such a result suggested that the amount of NH4+ adsorbed depended solely on the amount of NH4+ in contact with the zeolite surface. Results successfully established the application of zeolite-packed columns in removing NH4+ from real domestic treated wastewater and the effects of process parameters.

Mitigating water pollution by nitrogen fertilizers through amending ammonium sorption in an acid soil using Calciprill and sodium silicate

Use of nitrogen (N) fertilizers is gaining popularity to meet crop nutrient requirement for sustaining the food security of the increasing global population. However, improper management of N fertilizers in acid soils causes leaching and surface runoff because of excessive rainfalls and poor N retention in the tropics in particular. This results in N pollution in water bodies (also known as eutrophication), which degrades water quality to the detriment of aquatic ecosystems near farms. Thus, there is a need for using inorganic soil amendments such as Calciprill and sodium silicate to improve soil N adsorption because of the alkalinity and ability of these amendments to retain N for mitigating excessive N contamination in water bodies. To this end, this N sorption study was conducted to determine the effects of Calciprill and sodium silicate on ammonium (NH4+) adsorption and desorption in an acid soil (Bekenu series, Typic Paleudults). The soil was co-applied with different rates of Calciprill (80 %, 90 %, and 100 % Ca saturations) and sodium silicate (90, 105, 120, 135, and 150 kg ha−1), followed by the NH4+ adsorption capacity determination through the additions of NH4+ isonormal solutions at the five concentrations (0, 25, 50, 75, and 100 mg L−1) to establish a linear relationship between the amount of NH4+ absorbed (qe) and the amount of NH4+ left in the solution (Ce) after 24 h of equilibration. Apart from the soil only without any amendment (C0S0), there were another two additional treatments where the soil was added with Calciprill (100 % Ca saturation) (C3) and sodium silicate only (150 kg ha−1) (S5) to determine their respectively effects on N sorption. The collected data were fitted to the Langmuir and Freundlich isotherms. Thereafter, NH4+ desorption was determined using the same soil samples added with 2 mol dm−3. Compared with the soil without any amendment (C0S0), the Calcirpill alone (C3) and the combined use of Calciprill and sodium silicate significantly increased NH4+ adsorption at the NH4+ addition of 250 mg L̶1, suggesting that Calciprill is the amendment which dominantly increases NH4+ adsorption and the effects of amendments are more pronounced at the lower soil NH4+ concentration. The results also revealed that the NH4+ adsorption in the soils following the co-application of Calciprill and sodium silicate followed the assumption of Freundlich isotherm. Regardless of the NH4+ concentration used, the effects of Calciprill and sodium silicate on the NH4+ desorption remain unclear, which could be because of the ability of sodium silicate to stabilize the soil structure. This stabilization reaction might have impeded the dissolution of Calciprill and temporarily fixed the absorbed NH4+. These findings suggest that it is possible to use the amendments to amend NH4+ sorption in Bekenu series for mitigating NH4+ leaching and runoff to prevent eutrophication.

Novel pyrochlore type europium stannate – tungsten disulfide heterostructure for light driven carbon dioxide reduction and nitrogen fixation

The reduction of carbon dioxide (CO2) and nitrogen (N2) to value-added products is a substantial area of research in the fields of sustainable chemistry and renewable energy that aims at reducing greenhouse gas emissions and the production of alternative fuels and chemicals. The current work deals with the synthesis of pyrochlore-type europium stannate (Eu2Sn2O7: EuSnO), tungsten disulfide (WS2:WS), and novel EuSnO/WS heterostructure by a simple and facile co-precipitation-aided hydrothermal method. Using different methods, the morphological and structural analyses of the prepared samples were characterized. It was confirmed that a heterostructure was formed between the cubic EuSnO and the layered WS. Synthesized materials were used for photocatalytic CO2 and N2 reduction under UV and visible light. The amount of CO and CH4 evolved due to CO2 reduction is high in EuSnO/WS (CO = 104, CH4 = 64 μmol h−1 g−1) compared to pure EuSnO (CO = 36, CH4 = 70 μmol h−1 g−1) and WS (CO = 22, CH4 = 1.8 μmol h−1 g−1) under visible light. The same trend was observed even in the N2 fixation reaction under visible light, and the amount of NH4+ produced was found to be 13, 26, and 41 μmol h−1 g−1 in the presence of WS, EuSnO and EuSnO/WS, respectively. Enhanced light-driven activity towards CO2 and N2 reduction reactions in EuSnO/WS is due to the efficient charge separation through the formation of type-II heterostructure, which is in part associated with photocurrent response, photoluminescence, and electrochemical impedence spectroscopic (EIS) results. The EuSnO/WS heterostructure's exceptional stability and reusability may pique the attention of pyrochlore-based composite materials in photocatalytic energy and environmental applications.

Self-reporting electroswitchable colorimetric platform for smart ammonium recovery from wastewater

Recovery of ammonium from wastewater represents a sustainable strategy within the context of global resource depletion, environmental pollution and carbon neutralization. The present study developed an advanced self-reporting electroswitchable colorimetric platform (SECP) to realize smart ammonium recovery based on the electrically stimulated transformation of Prussian blue/Prussian white (PB/PW) redox couple. The key to SECP was the selectivity of ammonium adsorption, sensitivity of desorption to electric signals and visualability of color change during switchable adsorption/desorption transformation. The results demonstrated the electrochemical intercalation-induced selective adsorption of NH4+ (selectivity coefficient of 3–19 versus other cations) and deintercalation-induced desorption on the PB-film electrode. At applied voltage of 1.2 V for 20 min, the negatively charged PB-film electrode achieved the maximum adsorption capacity of 3.2 mmol g−1. Reversing voltage to −0.2 V for 20 min resulted in desorption efficiency as high as 99%, indicating high adsorption/desorption reversibility and cyclic stability. The Fe(III)/Fe(II) redox dynamics were responsible for PB/PW transformation during reversible intercalation/deintercalation of NH4+. Based on the blue/transparence color change of PB/PW, the quantitative relationship was established between amounts of NH4+ adsorbed and extracted RGB values by multiple linear regression (R2 = 0.986, RMSE = 0.095). Then, the SECP was created upon the unique capability of real-time monitoring and feedback of color change of electrode to realize the automatic control of NH4+ adsorption/desorption. During five cycles of tests, the adsorption process consistently peaked at an average value of 3.15±0.04 mmol g−1, while desorption reliably approached the near-zero average of 0.06±0.04 mmol g−1. The average time of duration was 19.6±1.67 min for adsorption and 18.8±1.10 min for desorption, respectively. With electroswitchability, selectivity and self-reporting functionalities, the SECP represents a paradigm shift in smart ammonium recovery from wastewater, making wastewater treatment and resource recovery more efficient, more intelligent and more sustainable.

Experimental study of CO2/H2/NH3 influence on CH4 flameless combustion process in semi-industrial furnace

A flameless combustion mode was employed in a semi-industrial furnace to investigate the effect of NH3 on CH4, which was diluted by CO2/H2 combustible mixtures, serving as the primary fuel. Emission characteristics, as well as toxic compounds and temperature distribution maps, were presented for selected fuels. The combustion system was tested at a constant firing rate of 150 kWth and a constant fuel bulk velocity of 85 m/s. We investigated the effects of equivalence ratio, fuel composition and volume share of NH3 in the fuel. It was found that the equivalence ratio and NH3 amount have the most significant impact on the emission of fuel nitric oxide in the flameless combustion process. The dilution of CH4 with CO2 affects the stretch rate, resulting in an increase in CO levels as well as promoting NO level growth. The calculated dimensionless Conversion Factor (CF) shows that the dilution gas, CO2, significantly impacts the reduction of NH3 to NO, but only for low-content fuel-bound nitrogen (up to 1%). The lowest values of CF were measured for a high equivalence ratio, corresponding to the typical oxygen content for flameless combustion process.

Estimating atmospheric nitrogen deposition within a large river basin using moss nitrogen and isotope signatures

Assessing flux and primary sources of the atmospheric nitrogen (N) deposition with high spatial resolution remained challenging. The epilithic moss is considered a suitable biological monitor to explore N deposition. Our study presented a detailed analysis of flux and major source contributions of ammonium (NH4+) and nitrate (NO3−) deposition using N and δ15N signatures of epilithic moss collected densely from the Yangtze River basin. The results showed a more negative δ15N and higher N concentration of the moss in cropland and urban area than in forest and grassland of the basin. A gradient of the estimated N deposition (9.6–34.0 kg ha−1 yr−1) occurred from the Tibetan Plateau to lower reaches, with amount of NH4+ was approximately three times higher than NO3− deposition. The contribution from volatilization to NH4+ deposition (33.28 ± 8.10%) was less than the contribution from combustion (66.72 ± 8.10%), inconsistent with the traditional findings that N fertilizer and livestock waste are the principal sources of NH3 emissions. Fossil fuel was the dominant sources of NO3− deposition, accounted for 70.22 ± 18.67%. From 2006 to 2019, the source contribution of N deposition in forest remained unchanged, while NH3 volatilization and fossil fuel emitted NOx in urban areas have increased. Our findings highlighted the importance of combustion sources to N deposition in the Yangtze River basin.

Experimental study on effects of ammonia enrichment on the thermoacoustic instability of lean premixed swirling methane flames

Ammonia (NH3) has recently emerged as a promising carbon-free energy carrier. Further development and application of NH3 as fuel in the gas turbine industry can significantly reduce the emissions of carbon dioxide (CO2) and contribute to the achievement of a carbon–neutral society. This study experimentally examined the thermoacoustic instability characteristics of a laboratory-scaled lean premixed gas turbine model combustor operated with different NH3 blending ratios with methane (CH4). Experiments conducted under a wide range of inlet velocities and equivalence ratios suggest that NH3 concentration is critical in determining the characteristics of the instability. Specifically, when the NH3 proportion is less than 50 %, the addition of NH3 causes a mode transition of the instability. However, when the content of NH3 is greater than 50 %, it is shown that the instabilities are suppressed, indicating that the addition of a certain amount of NH3 can enhance the stability of CH4 flames. Additional analysis of flame dynamics reveals that the introduction of NH3 causes the lengthening of the flame front and weakens heat release rate fluctuations in the flame root regions. Further Proper Orthogonal Decomposition (POD) analysis of the flow field shows that the instability modes are strongly coupled with periodic vortex motions of the flow dynamics along the shear layers. Finally, the mode shifting phenomena is successfully predicted by low-order thermoacoustic network modeling. It is suggested that the change in convective time delay caused by NH3 addition is responsible for such transitions.

Transport and distribution of residual nitrogen in ion-adsorption rare earth tailings

A large amount of nitrogen remains in ion-absorption rare earth tailings with in-situ leaching technology, and it continually ends up in groundwater sources. However, the distribution and transport of ammonium nitrogen (NH4+-N) and nitrate nitrogen (NO3−-N) across tailings with both depth and hill slopes is still unknown. In this study, the amount of NH4+-N and nitrate nitrogen (NO3−-N) was determined in tailings, and a soil column leaching experiment, served to assess the transport and distribution following mine closure. Firstly, a high concentration of NH4+-N in the leachate at the initial leaching stage was detected, up to 2000 mg L−1, and the concentration of NH4+-N clearly diminished as time passed. Meanwhile, the NH4+-N contents remained relatively high in soil. Secondly, both the content of NH4+-N and NO3−-N varied greatly according to vertical distribution after leaching lasting several years. The amounts of NH4+-N and NO3−-N in surface soil were much smaller than those in deep soil, with 3–4 orders of magnitude variation with depth. Thirdly, when disturbed by NH4+-N, the pH not only diminished but also changed irregularly as depth increased. Fourthly, although the amount of NO3−-N was smaller than that of NH4+-N, both their distribution trend was similar with depth. In fact, NH4+-N and NO3−-N were significantly correlated but this declined from the knap to the piedmont. Based on these results, it is suggested that mining activity could cause nitrogen to be dominated by NH4+-N and acidification in a tailing even if leaching occurs over several years. NO3−-N derived from NH4+-N transports easily and it becomes the main nitrogen pollutant with the potential to be a long-lasting threat to the environment around a mine.

Flux of NH3 release from dew evaporation in downtown and suburban Changchun, China.

Ammonia, as the only high-concentration alkaline gas in the atmosphere, plays an extremely important role in the initial nucleation process of aerosols. A rise in the concentration of NH3 after sunrise has been observed in many areas, known as the "morning peak phenomenon", which is likely related to the dew evaporation process because of the considerable amount of NH4+ present in dew. To investigate and compare the flux and rate of NH3 release from dew evaporation in downtown (WH) and suburban areas (SL), the dew amount and chemical makeup were measured and analyzed in Changchun, in northeastern China, from April to October 2021. The differences in the fraction of NH4+ released as NH3 gas and the NH3 emission flux and rate during the process of dew evaporation between SL and WH were identified. The results showed that the daily dew amount in WH (0.038 ± 0.017mm) was lower than that in SL (0.065 ± 0.032mm) (P < 0.01), and the pH in SL (6.58 ± 0.18) was approximately 1 pH unit higher than that in WH (5.60 ± 0.25). SO42-, NO3-, Ca2+ and NH4+ were the main ions in WH and SL. The ion concentration in WH was significantly higher than that in SL (P < 0.05), which was influenced by human activities and pollution sources. A total of 24%-48% NH4+ was released as NH3 gas during dew evaporation in WH, which was lower than the conversion fraction of SL dew (44%-57%). The evaporation rate of NH3 was 3.9-20.6ng/m2·s (9.9 ± 5.7ng/m2·s) in WH and 3.3-15.9ng/m2·s (8.6 ± 4.2ng/m2·s) in SL. The dew evaporation process makes an important contribution to the NH3 morning peak phenomenon, but it is not the only contributor.

The Effectiveness of Dolomite Phosphate Rock on Growth and Yield of Black Sesame (Sesamum indicum L.) in Paddy Field

Background: The study was carried out to determine the amount of the dolomite phosphate rock (DPR) on the growth and seed yield of black sesame in a paddy field. Methods: A randomized complete block design was used for the field experiment, which included four treatments, each with four replications. Treatments were applied without the DPR and with 0.25, 0.5 and 1.0 t ha-1 DPR. Result: Experimental results showed that sesame plants were fertilized with the following formula: 60 N x 60 P2O5 x 30 K2O kg ha-1. Moreover, the addition of 0.5 t ha-1 DPR increased plant height (129.7 cm), the number of leaves and pods per plant (47.4 pods), total chlorophyll content in leaves (12.4 µg/cm2), the number of seeds per pod and seed yield (1.61 t ha-1). The phosphate content increased in the stem but not in the leaves and seeds. The pH of the soil (0-20 cm) and the amount of NH4+, NO3- and PAvailable were also increased.

Nitrogen and Phosphorus Release Characteristics of Pipeline Sediments on Entering Different Water Bodies

Differences in the physical and chemical properties of reclaimed water (RW) and natural surface water (SW) lead to further differences in nitrogen and phosphorus release when pipeline sediments enter these water bodies. The release kinetics of nitrogen and phosphorus from pipe sediments with different particle sizes have been investigated. The results demonstrated that both SW and RW had a pH buffering effect after sediment addition, and the final pH (approximately 8.1) of RW was lower. The release of total phosphorus (TP) and ammonia nitrogen (NH4+-N) fitted the first-order kinetic model in which the release of TP reached equilibrium. TP release was inhibited in both SW and RW, with RW exhibiting the lowest (by a factor of 1.23~2.44) release (0.002 mg/g). The release of NH4+-N was promoted in both SW and RW; the maximum release in RW was 0.0188 mg/g. The amounts of NH4+-N released in SW and RW were 1.02–1.40 and 1.30–1.80 times that of the control group (CG), respectively. The percentage of TP and NH4+-N release in the three groups was highest in 75–154 μm pipe sediment, reaching 34.53% and 43.51% in SW and RW, respectively. These results can assist in the development of water quality evolution models for specific urban scenarios and provide important guidance for the precise regulation of water recharge quality during and after rainfall.

Dissolution Characteristics of Ammonium and Nitrate in Soil with Bottom Ash from Biomass Power Plant

Recently, biomass power plants are increasing as an alternative energy source to reduce the carbon emissions from fossil fuels. The amount of waste from biomass power plants increases and bottom ash is generally buried in soil. However, there is little research on the dissolution characteristics of nitrogen, a macronutrient in soil, using bottom ash (BA). To evaluate nitrogen dissolution in soil with BA, we mixed BA with soil, collected leachate for 5 weeks, and measured NH4+-N and NO3--N concentration in leachate. As a results, BA reduced the leaching of NH4+-N and NO3--N by up to 18% and 38%, respectively. The decrease of NH4+-N leaching is judged to be the result of increased NH4+-N adsorption due to the high pH of the bottom ash, and these results are often confirmed in other biochar. The NO3--N leaching also decreased, but it is not related to the adsorption capacity of BA, so further research is needed. These results suggested that BA reduces the contents of NH4+-N and NO3--N in the soil effluent, which can be used as an important indicator for using bottom ash in the soil.The amount of NH4+-N and NO3--N dissolution in soil using bottom ash from biomass power plant (average and standard deviation; 3 replicate). (left) Accumulation of NH4+-N; (right) Accumulation of NO3--N.

The greenhouse gas emission potential and phytotoxicity of biogas slurry in static storage under different temperatures.

With the booming development of biogas industry to treat organic waste in China, the by-product of biogas slurry was accompanied with a huge amount. Static storage process of biogas slurry was normally operated under different seasons before application to land which would cause nutrition decomposition and greenhouse gas emission. Thus, the aim of this study was to investigate the nutrition decomposition, greenhouse gas emission (CH4 and N2O), and phytotoxicity of biogas slurry under different static temperatures, furthermore to illuminate the network among them and functional microorganism. According to the results, higher temperature at 30 °C contributed to fast and complete degradation of COD. In addition, more quantity of NH4+ conversion and NO3- formation appeared at 30 °C. These factors resulted in relatively less crop toxicity together. CH4 was the dominant greenhouse gas emission than N2O and was highest in 30 °C treatment with total emission of 273.7 L/(m3·d) and greenhouse gas emission of 20.01 kg CO2e (carbon dioxide equivalent). Lower temperature was conductive to N reservation and reduction of greenhouse gas emission, but making against with stabilization of organic matter and crop safety. At the same dilution times (≤3) of biogas slurry with deionized water, higher temperature at 30 °C could reduce 30 days of storage time, but 10 °C was still unsafe for crop. Structural equation model was further illustrated the positive effect of temperature on NO3-, CH4, GI, and N2O and negative on COD and NH4+. These results could help to monitor the environmental risk, evaluate the maturity, guide the irrigation scheme, and regulate the static storage condition of biogas slurry under different seasons.

Growth of highly aligned ZnO nanorod arrays on zinc plates: Morphological and structural characterization

In this work, uniform and highly aligned ZnO nanorod arrays were simply synthesized on zinc plates by hydrothermal method using zinc–ammonia complex solution. Effects of ZnO seed layer formation, Zn(NO3)2 concentration and NH3/Zn(NO3)2 mole ratio (R) in the reaction medium on the morphology and crystal structure of nanorods were investigated in detail. ZnO nanorods grown on zinc surfaces were highly crystalline and had a hexagonal wurtzite structure, as revealed by XRD analysis. In addition, the dominant crystal growth direction was in c-axis, indicating the verticality of the nanorods. SEM images showed that one-dimensional (1D) ZnO nanorods with high verticality and number density were synthesized on seeded plates whereas randomly oriented arrays were grown on non-seeded surfaces. Increase in the Zn2+ concentration changed the top ends of the rods from tapering to hexagonal ends; and also led to an increase in the average size and verticality of the nanorods. The increase in R value (or i.e., amount of NH3) caused the rods to misalign on the surface and decrease in size. The size of well-aligned nanorods can be adjusted from 50 to 260 nm in diameter and 0.11 to 6 m in length by changing the reaction parameters, implying their large potential to be used in photocatalytic and also in electronic applications.

Controllable synthesis of Sn0.33WO3 tungsten bronze nanocrystals and its application for upconversion luminescence enhancement

The development and utilization of novel semiconductor nanocrystals with remarkable localized surface plasmon resonance (LSPR) effect is one of the current research hotspots. Tungsten bronze nanocrystals are a class of semiconductor nanocrystals with strong LSPR effect discovered recently. The synthesis of tungsten bronze nanocrystals by introducing high valence metal ions, the regulation and application of the corresponding LSPR effect are still under further exploration. In this paper, Sn 0.33 WO 3 nanocrystals with different crystal phases and morphologies were synthesized using different types of Sn precursors and different amounts of NH 4 F. Acid radical ions provided by different types of Sn precursors is an important factor affecting the LSPR absorption characteristics of Sn 0.33 WO 3 nanocrystals. Sn 0.33 WO 3 nanosheets with strong LSPR absorption synthesized with stannous oxalate were used as a representative to enhance the upconversion luminescence of NaYF 4 :Yb 3+ , Er 3+ . Compared with Glass/NaYF 4 :Yb 3+ , Er 3+ film, the upconversion luminescence intensity of the layered Glass/Sn 0.33 WO 3 /PMMA/NaYF 4 :Yb 3+ , Er 3+ film was enhanced by 34 times. The LSPR effect of Sn 0.33 WO 3 enhances the excitation field of NaYF 4 :Yb 3+ , Er 3+ nanocrystals, resulting in significant upconversion luminescence enhancement of NaYF 4 :Yb 3+ , Er 3+ in the layered Glass/Sn 0.33 WO 3 /PMMA/NaYF 4 :Yb 3+ , Er 3+ film. The present work is helpful for people to study the development and application of semiconductor nanocrystals with LSPR effect.

Water Chemical Characteristics and Safety Assessment of Irrigation Water in the Northern Part of Hulunbeier City, Grassland Area in Eastern China

Hulun Buir Grassland is a world-famous natural pasture. The Chenbalhu Banner coalfield, the hinterland of the grassland, is located on the west slope of the Great Khingan Mountains and on the north bank of the Hailar River in China. The proven geological reserves of coal are 17 billion tons. Hulun Buir Grassland plays a role in the ecological barrier, regional coal industry, power transmission from west to east and power transmission from north to south. The proportion of local groundwater in irrigation, domestic and industrial production water sources is about 86%. The large-scale exploitation of coal resources and the continuous emergence of large unit and coal-fired power plants have consumed a large amount of local water resources, resulting in the decrease of the local groundwater level and changing the natural flow field of groundwater. This paper studies the background hydrochemical values and evaluates the irrigatibility of the whole Chenbaerhu Banner coalfield, and studies the impact of coal industry chains such as mining areas and coal chemical plants on the hydrochemistry characteristics of groundwater. The above two studies provide important guiding values for guiding local economic structure planning, groundwater resources exploitation and ecological governance. The study found that Na+ and HCO3− in the groundwater in the study area occupy a dominant position. Referring to the comparison of the lowest values of three types of water standards in the Quality Standards for Groundwater (GB/T14848-2017), the amount of NH4+, Na+ and NO2− exceeding the standard is close to more than 30%. The main chemical types of river water in the study area are HCO3− Na and HCO3− Ca·Na, the main chemical types of surface water are HCO3− Na and HCO3− Na·Ca, and the main chemical type of confined water is HCO3−Na. The formation of hydrochemical types is mainly affected by the dissolution, filtration and evaporation of rocks, specifically the dissolution and filtration of sodium and calcium salts. The chemical correlation analysis of groundwater shows that there are abnormal values at many points in the study area. Further combining with the horizontal comparison of surface human activities in the study area, it shows that the influence scope of coal mine production and coal chemical plants on groundwater is extremely limited. The local groundwater is mainly polluted by a large quantity of local cattle and sheep manure, industrial and domestic sewage pollution and farmland fertilizer.

An integrated pickling-bating technology for reducing ammonia-nitrogen and chloride pollution in leather manufacturing

Currently, ammonia-nitrogen (NH3–N), chloride (Cl−) and chromium (Cr) pollution from leather manufacturing processes attracts much attention and limited the sustainable development of the leather industry. In this paper, conventional trypsin bating and high-salt pickling procedures were substituted by a salt-free pickling-bating system, using acidic protease L80A and salt-free pickling agent naphthalene sulfonic acid (NSA); a novel integrated technology comprising non-ammonia bating, salt-free pickling and high-exhausting chrome-tanning methods was established to reduce NH3–N, Cl− and Cr pollution. The results indicated that the properties of the leather produced by the established method were better than the conventional method. Furthermore, the established integrated salt-free pickling-bating technology resulted in the almost elimination of NH3–N and chloride pollution from waste effluent. The total Cr utilization ratio was increased to 95% from 80%, the total Cr discharge was reduced by 74%. Scale-up experiments further verified the acceptability of this novel technology in terms of physical and organoleptic properties of the resultant leather. It can be easy to predict that the effluent liquors with a little amount of NH3–N, chloride and chromium can be disposed of conveniently. We suppose that the established novel technology is an environment-friendly technology and a way forward in the development of the modern sustainable leather industry.

Branched core-shell a-TiO2@N-TiO2 nanospheres with gradient-doped N for highly efficient photocatalytic applications

A branched core-shell nanosphere composed of an anatase TiO2 (a-TiO2) core and a TiO2 nanobranch shell with gradient-doped N (a-TiO2@N-TiO2) is synthesized by a simple in situ doping method, in which mixed crystal anatase-rutile TiO2 (ar-TiO2) nanosphere is first prepared by oxidizing Ti using H2O2, and then is etched by NH3·H2O to form (NH4)2TiO3 nanobranches, which is converted into a-TiO2@N-TiO2 following an ambient annealing process. The diameter of a-TiO2 core is ∼500 nm, and the thickness of N-TiO2 branched shell is ∼100 nm with gradually increased N concentration from the bottom to the edge. Ultra-thin amorphous coating layers on the branches are also observed. The morphology of the composites could be further tuned by the amount of NH3·H2O, and its effect on the photocatalytic performance is also investigated. The optimized a-TiO2@N-TiO2 shows an outstanding hydrogen evolution rate of 308.1 µmol g−1 h−1 under air mass (AM) 1.5 illumination, and also exhibits highly active in photocatalytic degradation of various refractory organic pollutants, including organic dyes, phenols, antibiotics, and personal care products, with removal ratios higher than 96% after 2 h operation. This can be due to the gradient-doped N-TiO2 nanobranches, which not only provide bending band structure and defect level derived from the N impurities and O vacancies, resulting the formation of n-n+ heterojunctions to improve the charge separation, but also enhance the charge transfer at the liquid-solid interface due to the numerous nanobranches and amorphous coating layers.

Effects of butyrate\u2212 on ruminal Ca2+ transport: evidence for the involvement of apically expressed TRPV3 and TRPV4 channels

The ruminal epithelium absorbs large quantities of NH4+ and Ca2+. A role for TRPV3 has emerged, but data on TRPV4 are lacking. Furthermore, short-chain fatty acids (SCFA) stimulate ruminal Ca2+ and NH4+ uptake in vivo and in vitro, but the pathway is unclear. Sequencing of the bovine homologue (bTRPV4) revealed 96.79% homology to human TRPV4. Two commercial antibodies were tested using HEK-293 cells overexpressing bTRPV4, which in ruminal protein detected a weak band at the expected ~ 100 kDa and several bands ≤ 60 kDa. Immunofluorescence imaging revealed staining of the apical membrane of the stratum granulosum for bTRPV3 and bTRPV4, with cytosolic staining in other layers of the ruminal epithelium. A similar expression pattern was observed in a multilayered ruminal cell culture which developed resistances of > 700 Ω · cm2 with expression of zonula occludens-1 and claudin-4. In Ussing chambers, 2-APB and the TRPV4 agonist GSK1016790A stimulated the short-circuit current across native bovine ruminal epithelia. In whole-cell patch-clamp recordings on HEK-293 cells, bTRPV4 was shown to be permeable to NH4+, K+, and Na+ and highly sensitive to GSK1016790A, while effects of butyrate− were insignificant. Conversely, bTRPV3 was strongly stimulated by 2-APB and by butyrate− (pH 6.4 > pH 7.4), but not by GSK1016790A. Fluorescence calcium imaging experiments suggest that butyrate− stimulates both bTRPV3 and bTRPV4. While expression of bTRPV4 appears to be weaker, both channels are candidates for the ruminal transport of NH4+ and Ca2+. Stimulation by SCFA may involve cytosolic acidification (bTRPV3) and cell swelling (bTRPV4).