Low Initial pH Research Articles

Study on the effect of surface organic acid treatment on inhibiting nitrogen loss in trough composting

ABSTRACT To reduce the ammonia loss during the trough composting process and the problem of low initial pH of the compost due to one-time addition of organic acids. In this study, we investigated the feasibility of buffering the pH of the compost and controlling the ammonia emission through the addition of dilute acetic acid sprayed on the surface of the compost pile after several pile-turnings in the trough composting process. The results showed that the spraying of acetic acid did not have a significant difference in the effect on the initial pH and maintained a slightly alkaline environment throughout the composting process, which led to an increase in the degradation rate of 58.38% at the end of the composting process. Compared with natural composting, the pile-turning of trough compost increased the ammonia volatilisation by 125.53% and nitrogen loss by 10.75% during the composting process, but the spraying of 0.005 mol/L dilute acetic acid solution and water on the surface layer of the heap could reduce the ammonia emission of the heap, which was reduced by 36.31% and 17.81%, and the rate of nitrogen loss was reduced by 12.63% and 3.59%, respectively. This study suggests that acetic acid is a suitable additive for composting. Spraying acetic acid after compost turning not only stabilises compost pH, but also reduces ammonia volatilisation loss. It provides a reference for the efficient ammonia reduction technology of compost.

Mechanism and kinetics of scorodite formation in arsenic-bearing solutions using Fe(OH)3 as a solid iron source

Recently, solid iron sources have been used for scorodite synthesis in arsenic-bearing wastewater from nonferrous metallurgy. Immobilising arsenic-solution as scorodite via iron hydroxide (Fe(OH)3) solid iron source is an important method for controlling arsenic pollution. The evolution behavior of scorodite during its formation in high arsenic solution have been rarely investigated. In this paper, the mechanism and kinetics of scorodite formation using Fe(OH)3 in arsenic-bearing solution were investigated. This work was divided into three parts. Firstly, the influencing parameters were investigated, revealing that the dissolution of Fe(OH)3 and scorodite generation accelerated at lower initial pH and higher reaction temperature. Increasing Fe/As ratio delayed scorodite crystallisation, which was in turn enhanced by elevating arsenic concentration. Secondly, the mechanism of scorodite formation was investigated, revealing that Fe(OH)3 underwent acidic dissolution to form a precursor. Subsequent scorodite formation had a ΔrGmθ ranging from −69.39 kJ·mol−1 to −15.64 kJ·mol−1. Residual As was absorbed and converted into Fe(OH)3@scorodite. Thirdly, the chemical kinetics were investigated, showing that activation energy (Ea) for Fe(OH)3 dissolution was 72.54 and 105.37 kJ·mol−1 at Stages I and II, respectively, whereas it was 105.97 kJ·mol−1 for residual As absorption-conversion at Stage III outweighing the Ea of As-Fe coprecipitation. The restrictive steps were Fe(OH)3 dissolution and residual arsenic absorption-conversion. This proposed method can be applied for environment-friendly treatment of 10－40 g/L of arsenic-bearing industrial effluent for scorodite formation. Overall, this research confirmed the formation of scorodite via Fe(OH)3 and can potentially provide feasible schemes for eliminating arsenic-bearing acidic waste, dust, and anode slime from nonferrous metallurgical processes.

The impact of premature rupture of membrane on neonatal outcomes in infants born at 34 weeks gestation or later.

Premature rupture of membranes (PROMs) is a known risk for adverse neonatal outcomes, often leading to neonatal hospitalization due to suspected perinatal infection or other issues. This study assesses PROM's clinical impact on neonatal outcomes in infants born at 34 weeks of gestation or later. We studied hospitalized neonates born between December 2018 and November 2019, with gestational ages of 34 weeks or more and PROM diagnosis. We extracted patient data from clinical records, including demographics, maternal history, medical profiles, and neonatal outcomes. Neonates were categorized based on symptoms, PROM duration, neonatal intensive care unit (NICU) stay, and respiratory support. Data underwent thematic analysis. Of 275 neonates, the average PROM duration was 7.9 ± 8.1 hours, with 247 cases (89.8%) showing symptoms. Among them, 34 (12.4%) had PROM lasting over 18 hours, 48 (17.5%) were born prematurely, and 79 (28.7%) required intensive care. Symptomatic neonates had significantly higher rates of needing intensive care, respiratory support, prolonged antibiotics, and extended hospitalization ( p < 0.05). NICU stays (≥3 days) were significantly associated with prematurity (odds ratio [OR] = 5.49; 95% CI, 2.39-12.60) and an initial pH level <7.25 (OR = 3.35; 95% CI, 1.46-7.68). Extended respiratory support (≥3 days) was significantly correlated with tocolysis ≥7 days (OR = 13.20; 95% CI, 3.94-44.20), Apgar score <7 at 1 minute after birth (OR = 4.28; 95% CI, 1.67-10.97), and inadequate intrapartum antibiotic prophylaxis (IAP) (OR = 2.34; 95% CI, 1.04-5.23). Neonates born at or after 34 weeks of gestation with PROM should undergo vigilant monitoring if early symptoms (<24 hours) manifest. Risk factors for requiring NICU care or extended respiratory support (≥3 days) include prematurity, low initial pH (<7.25), prolonged tocolysis requirement (≥7 days), an Apgar score below 7 at 1 minute, and inadequate IAP.

V-A ECMO window of opportunity: identification of potential responders after an acute myocardial infarction complicated by cardiogenic shock

Abstract Funding Acknowledgements None. Background V-A ECMO is designed to supply oxygen demands in patients with circulatory failure. Neutral results obtained in recent cardiogenic shock (CS) trials are probably related to the inclusion of a high proportion of patients with SCAI C stage, in many of whom, the device might not provide hemodynamic benefit despite the addition of inherent complications. Mechanical circulatory support could potentially have a role only for patients in SCAI D-E stages. Purpose Our aim was to explore the excess in mortality explained by a SCAI D-E stage at 12h, compared to a SCAI A-C stages at 12h, in patients admitted due to an acute myocardial infarction (AMI) complicated by CS (stages C-E at admission). Additionally, we aimed to identify those factors at admission—clinical, electrocardiographic, gasometrical, echocardiographic, and angiographic—which predict whether a patient will progress to SCAI D-E stages within the subsequent 12h from CS onset. Main Outcome: SCAI D and E stage at 12h. Methods We retrospectively analysed those patients admitted due to an AMI in SCAI C-E stages at admission, that had been prospectively screened for EUROSHOCK trial. We classified the patients in two groups: "SCAI A-C" and "SCAI D-E" at 12 hours and conducted a survival analysis. Additionally, we conducted a univariate and multivariate analysis including arrival potential predictors for SCAI D-E at 12 hours. Results A total of 72 patients were included. At admission 25 patien were in SCAI D-E. At 12 hours, 42 patients were in SCAI D-E, and this group showed a higher 30-day mortality rate particularly explained by an excess of mortality within the first 7 days (Figure 1). There were no significant differences between groups in most baseline characteristics (Table 1) such as age or gender. We observed a fewer proportion of previous chronic treatment with negative inotropes (betablockers and calcium channel antagonists) in the SCAI D-E group. Overall, anterior ST elevation on EKG was more prevalent among SCAI D-E group, median pH lower and median glycaemia and lactate higher. In the multivariate analysis after adjustment by confounders, the independently predictors at arrival for the development of a SCAI D-E stage at 12h were culprit LAD, cardiac arrest in the cath Lab, low initial median pH and final TIMI &amp;lt;3 result. Conclusions In a cohort of AMI patients complicated by CS, those patients who remained in a SCAI D-E stage at 12 hours from CS onset, compared to those in A-C, showed a 26% excess mortality at 30-day follow-up, especially during the first week. Patients who presented with LAD as the culprit artery, low initial pH, cardiac arrest in the cath lab, and got a TIMI &amp;lt;3 result after PCI were independently associated with the development of SCAI D-E within 12 hours from admission. Patients meeting these criteria could benefit from early selective mechanical support and be taken into consideration in the design of future randomized controlled trials.

Insights into selective leaching of rare earths from weathered crust elution-deposited rare earth ore using magnesium sulfate

In this paper, a multi-stage leaching process for the weathered crust elution-deposited rare earth ore was proposed using MgSO4 as a leaching agent. The results indicate that with increasing the concentration of MgSO4 from 0.5 wt%–1.0 wt% to 2.0 wt%–4.0 wt%, the peak concentrations of rare earths increase from 1.87–3.59 to 5.49–10.21 g/L, and the collection periods of leach solution are shortened from 0.85–1.54 to 0.31–0.47 (liquid-to-ore ratio). When the rare earth ore is leached with leaching agent solution with high initial pH (3.0–5.0), the rare earths and aluminum are predominantly leached by Mg2+ instead of H+. However, H+ participate in the leaching process of rare earths and aluminum at lower initial pH (1.5–3.0) of the leaching agent solution. Especially, when the initial pH of leaching agent solution is 2.0, a large amount of aluminum is leached when the liquid-to-ore ratio is greater than 1.2. Based on the above insights, increasing the initial pH (3.0–5.0) of leaching agent solution in the injection stage using high-concentration MgSO4 (>1.0 wt%) can increase the peak concentration of rare earths in the leach solution and shorten the collection period. However, in the injection stage using low MgSO4 concentration (<1.0 wt%), an initial pH of leaching agent solution of 2.0 is selected to reduce the leaching amount of aluminum and the consumption of MgSO4. Comparing to the leaching process using constant MgSO4 concentration (2.0 wt%, initial pH of 5.0), the leaching efficiency of rare earths using a multi-stage leaching process is approximately equal (about 94.6%) under optimal conditions. The leaching amount of aluminum is reduced by 16.9%. The consumption of MgSO4 is reduced by 67.1%.

Regeneration of As(V)-loaded granular activated carbon through electrocoagulation.

As(V)-loaded granular activated carbon was regenerated through electrocoagulation assisted by elution with NaCl. Adsorption of As(V) by activated carbon was highest at pH6, and subsequent desorption in water was highest at pH 11, followed by pH3. Lower initial pH improved arsenic removal during electrocoagulation, NaCl concentration was insignificant, but removal increased with current density. Adding Fe(II) before electrocoagulation led to an improved removal efficiency up to a concentration of 30 mg/L. Regeneration of As(V)-loaded activated carbon increased with current density and time up to a maximum of 85%. An increase in NaCl concentration to 6000 mg/L further improved regeneration to 92%. Regeneration at a lower current density only dropped slightly from 54% to 51% when doubling activated carbon concentration, demonstrating excellent scalability. Repeated adsorption-desorption tests were performed, where 81% and 69% regeneration were obtained after four regenerations with NaCl concentrations of 6000 and 750 mg/L, respectively. NaCl concentration in the tested range did not influence electrocoagulation but improved regeneration through elution. The combination of electrocoagulation and elution facilitated a higher regeneration efficiency, meanwhile removing As(V) from the solution through adsorption on iron hydroxide. PRACTITIONER POINTS: As(V)-loaded activated carbon was regenerated by electrocoagulation with elution. Regeneration increased with regeneration time and current density up to 85%. Addition of 6000 mg/L NaCl further increased regeneration to 93%. Regeneration of 82% was achieved after four regenerations. NaCl did not affect electrocoagulation but improved regeneration through elution.

Biogas Production from Palm Oil Mill Effluent at Low pH

The palm oil industry in Malaysia has aided our economy, but with any thriving industry comes the baggage of industrial waste. This paper focuses on palm oil mill effluent (POME), a waste product formed by palm oil milling operations. The objective of this paper is to evaluate the ability of POME to generate biogas through acid and heat pre-treatment methods. The feasibility of producing biogas at pH levels lower than 5 was investigated. The inoculum is effective microbe 1 (EM1), and the substrate is a liquid POME. Hydrochloric and phosphoric acid were used in this study, and the effect of low initial pH on biogas generation was investigated. The results show that POME alone produced the highest biogas volume (20.1 Nml). However, POME incubated with activated EM1 inoculant at low pH (3.74) generated consistent biogas during 57.75 hours of digestion. In conclusion, the EM1 is a good source of inoculum for POME treatment at low pH, with no pre-treatment required. The pre-treatment methods proposed in this study could have opened new doors for bio-renewable energy research, particularly in agricultural biomass, since substrate pre-treatment can enhance biogas production.

Adsorption of Nickel Ions on the γ-Alumina Surface: Competitive Effect of Protons and Its Impact on Concentration Profiles.

Mesoporous γ-alumina is used as an adsorbent in the decontamination of water from heavy metals (e.g., nickel and cobalt) and as a support for heterogeneous catalysts prepared by impregnation. In these cases, alumina extrudates are in contact with aqueous solutions containing precursors of the active metal phase to be deposited. The proton concentration (or pH) in the metal solution in contact with alumina can impact the adsorption efficiency of decontamination processes and the activities of catalysts. Yet, it is difficult to quantify the effect of the pH inside the pores since protons are not detected by classical imaging techniques. In this article, the effect of protons on nickel adsorption on alumina is evaluated using a novel technique coupling liquid analysis (pH, conductivity, and UV/vis) and laser-induced breakdown spectroscopy (or LIBS) analysis of concentration gradients inside the solid. Both methods are in excellent agreement. The results show a slow diffusion of protons inside alumina pores (diffusion continues even after 940 min), yielding high proton concentration gradients. On the other hand, the nickel species penetrate the extrudates faster but are slowly displaced by protons under certain operating conditions. As a result, different metal concentration profiles are obtained, depending on the initial pH and contact time. These findings are interesting in catalysis since they prove the possibility of controlling the deposition of the active metal on catalysts by regulating the operating conditions of impregnation. For typical industrial impregnation times (a few minutes to 1 to 2 h), protons do not have enough time to deeply penetrate inside extrudates, so the initial pH of the metal solution will have nearly no effect on the metal distribution. Conversely, decontamination processes have much longer contact times; therefore, lower initial pH values should have negative impacts on the adsorption efficiency due to the protons displacing the adsorbed nickel.

The Influence of pH Dynamics on Modeled Ammonia Emission Patterns of a Naturally Ventilated Dairy Cattle Building

Ammonia emission rates from naturally ventilated livestock housing systems can be estimated in multiple ways. By coupling different modeling approaches towards a semi-mechanistic barn-scale ammonia emission model, we investigated the influence of urine puddle pH dynamics on the (sub)daily and seasonal pattern of ammonia emissions. We compared the simulated ammonia emission patterns using about ten months of on-farm measurements obtained from a naturally ventilated dairy cattle building with a scraped solid floor in Northern Germany. The dataset included gas concentration measurements as well as wind data (ranging from 0 m s−1 to about 8.6 m s−1) and air temperature data (ranging from about −4 ∘C to about 32 ∘C), the average number of housed cows (about 380) and information on the average cow mass (about 700 kg). In addition, the average dry matter intake, total gross energy intake and nitrogen intake were used to model the ammonia emission potential. In the emission modeling, we considered two potential types of pH dynamics in the urine puddles: a saturating scenario and a peaking scenario. For both of them, 21 different combinations of initial pH and maximum pH were considered within a range of 6.5 to 11. We showed that the non-linear interaction of the puddle pH and temperature caused specific emission patterns, where the degree of influence of the two parameters changed over the course of the emission process. Low initial pH values together with high asymptotic pH values were associated with the largest emissions. Considering the same asymptotic pH value, the higher the initial pH value, the lower the observed emissions; especially when assuming peak pH dynamics, the emission values were significantly lower. In natural pH settings (i.e., low to intermediate initial pH and intermediate asymptotic pH), the winter emissions were considerably lower than the summer emissions (i.e., the winter emission was about half of the summer emission, as observed in the on-farm studies). In contrast, artificial pH settings with high pH values led to markedly lower emissions in the summer (i.e., the summer emission was about the same as winter emission), reducing the total annual emission value. Our sensitivity study indicated that the urine puddle alkalizing dynamics play a key role in the overall emission model accuracy in order to capture seasonal and diurnal variability of the ammonia emission of naturally ventilated dairy cattle barns in mechanistic modeling approaches. Thus, future studies should investigate the range of pH dynamics that naturally occur in urine puddles in cattle barns depending on the flooring material, the entry of litter or feed leftovers, the cleaning and cooling system (e.g., in terms of use of water) and so on in order to further refine the emission model.

Buffering Capacity Comparison of Tris Phosphate Carbonate and Buffered Peptone Water Salmonella Pre-Enrichments for Manufactured Feed and Feed Ingredients.

Various culture-based methods to detect Salmonella in animal feed have been developed due to the impact of this bacterium on public and animal health. For this project, tris phosphate carbonate (TPC) and buffered peptone water (BPW) buffering capacities were compared as pre-enrichment mediums for the detection of Salmonella in feed ingredients. A total of 269 samples were collected from 6 feed mills and mixed with the pre-enrichments; pH was measured before and after a 24 h incubation. Differences were observed when comparing pH values by sample type; DDGS and poultry by-product meal presented lower initial pH values for TPC and BPW compared to the other samples. For both TPC and BPW, meat and bone meal presented higher final pH values, while soybean meal and peanut meal had lower final pH values. Furthermore, for BPW, post cooling, pellet loadout, and wheat middlings reported lower final pH values. Additionally, most feed ingredients presented significant differences in pH change after 24 h of incubation, except DDGS. From meat and bone meal samples, four Salmonella isolates were recovered and identified: three using BPW and one using TPC. TPC provided greater buffer capacity towards neutral pH compared to BPW, but BPW was more effective at recovering Salmonella.

Is green manure a viable substitute for inorganic fertilizer to improve grain yields and advance carbon neutrality in paddy agriculture?

Green manure is a widely applied to increase grain yield, while it also attributes to greenhouse gas (GHG) emissions in agriculture ecosystems. Combining green manure with inorganic fertilizer inputs is a common practice that can influence soil GHG emissions and grain yield, however, its impacts on grain yield and global warming potential (GWP) under different initial soil conditions before rotating experiments and agronomic management in paddy fields remain unclear. We synthesized 508 data pairs to evaluate the responses of CO2 emissions, CH4 emissions, N2O emissions, and grain yield to combined inputs of green manure plus inorganic fertilizer compared with only inorganic fertilizer application. Our findings indicate that both inorganic fertilizer plus extra green manure (GM-E) and green manure substitutes for inorganic fertilizer (GM-S) could increase CO2 emissions (22.5 %−76.8 %), CH4 emissions (100 %−103 %), N2O emissions (29.8 %−50.9 %), and yield (2.21 %−19.6 %). Except for GM-E, which showed a non-significant increase in grain yield. The initial soil properties before rotating experiments, the types and timing of green manure application were key drivers of GHG emissions and yield, and extra green manure applied in areas with low initial soil pH and high C:N can increase GWP and yield. Overall, the mixed green manure application had greater impact than leguminous or non-leguminous green manure applied alone. The responses of GHG emissions and yield to GM-S were modulated by mean annual precipitation and initial soil properties before rotating experiments, and green manure substitutes for inorganic fertilizer in areas with high initial soil pH and low C:N can increase GWP and yield. Meanwhile, excessive precipitation caused a reduction in yield and a significant increase in GWP intensity. Our results showed that extra green manure applications of less than 68.1 kg N ha−1 would not significantly increase GWP. Therefore, an effective green manure strategy can achieve a win-win situation for the dual challenge of agricultural production and climate change mitigation.

Floating TiO2/expanded perlite prepared for degradation of sulphadiazine and sulphamethoxazole

ABSTRACT Photocatalysis treatment is a promising technology to eliminate antibiotic pollution. In this study, a floating TiO2/expanded perlite (TiO2/EP) catalyst was successfully prepared using a simple dip-coating method. The photocatalytic degradation effects of sulphadiazine (SDZ) and sulphamethoxazole (SMZ) were investigated. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) measurements demonstrated that TiO2 has been immobilised on the surface of EP. The TiO2/EP with TiO2 dip-coating three layers displayed the best degradation effect of SDZ and SMZ and the loading amount of TiO2 was 20wt%. The photocatalytic degradation rates of SDZ and SMZ were above in the TiO2/EP+UV system reached over 92% within 75 min, and followed a pseudo-first-order kinetic model. Low initial concentration (<10 mg L−1) and neutral pH water environment were found to be favourable for the photocatalytic degradation of SDZ and SMZ. Additionally, electrolyte ions (SO4 2- and Cl−) and humic acid (HAc) showed inhibitory effects on the degradation of SDZ and SMZ. However, HCO3 − inhibited the degradation of SDZ and SMZ at low concentration and had the opposite effect at high concentrations. This study provides valuable data for the designing of composite photocatalysts for efficient removal of SDZ and SMZ in real water systems.

High performance and mechanism of Tl(I) removal from solution by synergetic application of nanowire γ-MnOOH@biochar and free radicals: Implications to AMD treatment

Thallium (Tl) is a rare heavy metal with extreme toxicity, and Tl pollution in water bodies has frequently emerged globally. It is a challenge to effectively remove the predominant monovalent thallium from acid wastewater. In this study, highly efficient Tl(I) removal from aqueous solution was realized through synergetic application of nanowire γ-MnOOH@biochar and free radicals (·OH and SO4−) generated via activating persulfate. This method exhibited an overall robust Tl removal capacity in a wide pH range, even can remove over 97% of Tl at pH = 2, and maintain generally stable in the presence of coexisting ion and organic matter. The Tl removal capacity at low initial pH of the solution was up to 20% higher than that at alkaline conditions and fast adsorption realized in the first 10 min. This study offers a novel alternative of Tl-bearing wastewater treatment with facilely engineered composite that combines advanced oxidation and adsorption techniques, thus potentially serving as a promising method towards Tl removal from challenging acid mine drainage.

Utilization of olive mill wastewater for selective production of lipids and carotenoids by Rhodotorula glutinis.

Olive mill wastewater (OMW) is a zero-cost substrate for numerous value-added compounds. Although several studies on the production of lipids and carotenoids by Rhodotorula glutinis in OMW exist, none of them has specifically focused on the conditions for a target lipid or carotenoid. This study presents cultivation conditions that selectively stimulate the cell biomass, individual carotenoids and lipids. It was found that supplemental carbon and nitrogen sources as well as illumination affected cell biomass the most. High temperature, low initial pH, illumination, lack of urea and presence of glycerol stimulated the lipid synthesis. The highest total lipid content obtained in undiluted OMW supplemented with urea was 11.08 ± 0.17% (w/w) whilst it was 41.40 ± 0.21% (w/w) when supplemented with glycerol. Moreover, the main fatty acid produced by R. glutinis in all media was oleic acid, whose fraction reached 63.94 ± 0.58%. Total carotenoid yield was significantly increased with low initial pH, high temperature, illumination, certain amounts of urea, glycerol and cultivation time. Up to 192.09 ± 0.16μg/g cell carotenoid yield was achieved. Torularhodin could be selectively produced at high pH, low temperature and with urea and glycerol supplementation. To selectively induce torulene synthesis, cultivation conditions should have low pH, high temperature and illumination. In addition, low pH, high temperature and urea supplementation served high production of β-carotene. Up to 85.40 ± 0.76, 80.67 ± 1.40 and 39.45 ± 0.69% of torulene, torularhodin and β-carotene, respectively, were obtained under selected conditions. KEY POINTS: • Cultivation conditions selectively induced target carotenoids and lipids • 41.40 ± 0.21% (w/w) lipid content and 192.09 ± 0.16μg/g cell carotenoid yield were achieved • Markedly high selectivity values for torularhodin and torulene were achieved.

Feasibility of successive hydrogen and methane production in a single-reactor configuration of batch anaerobic digestion through bioaugmentation and stimulation of hydrogenase activity and direct interspecies electron transfer

Two-stage anaerobic digestion is a promising way to increase the efficiency of decomposition of organic waste. However, spatial separation of stages makes this technology less economically attractive. In this work, we studied a model of two-stage anaerobic digestion with stages separated in time in one reactor. To implement this model, we used a combination of (1) bioaugmentation with a hydrogen-producing Thermoanaerobacterium thermosaccharolyticum SP-H2, resistant to low pH, (2) setting a low initial pH (5.5) to reduce the activity of hydrogenotrophic methanogens, (3) supplementing additives in the form of soluble iron (II) and granular activated carbon (GAC) to stimulate hydrogenase activity and direct interspecies electron transfer (DIET), respectively. For comparison, two methanogenic inoculums with different dominant microbial groups and initial iron concentrations were used. With the simultaneous addition of GAC and iron (II), sequential production of hydrogen and methane was observed for both methanogenic inoculums. Without the addition of GAC, methane formation was practically not observed, which, apparently, indicated the impossibility of syntrophic degradation of acidogenesis products due to the high partial pressure of hydrogen and the absence of conductive material for activation of DIET. Significant differences in hydrogenase activity and the kinetics of hydrogen and methane formation according to the modified Gompertz equation depending on the iron content in the system may indicate the importance of this additive. Further studies should be aimed at determining the optimal initial pH, concentrations of stimulating additives, bioaugmentation and methanogenic cultures, as well as confirming the stability of the proposed single-reactor two-stage anaerobic digestion system in semi-continuous mode.

Outcomes of children with severe diabetic ketoacidosis managed outside of a pediatric intensive care unit.

Diabetic ketoacidosis (DKA) is a life-threatening complication of type 1 diabetes. Our objective was to determine if children with severe DKA without alteration in mental status can be managed safely on a general children's medical unit. Single center retrospective study of 191 patient encounters among 168 children admitted to the children's medical unit (CMU) at Primary Children's Hospital between 2007 and 2017 with severe DKA (pH <7.1 and/or bicarbonate <5mmol/L). Chart review identified complications including death, transfer to the intensive care unit (ICU), incidence of cerebral edema, and hypoglycemia. We compared patients requiring ICU transfer with those who did not with respect to demographics, laboratory findings at presentation, therapeutic interventions, length of stay, and cost. Of 191 patient encounters, there were 0 deaths (0%, 95% CI 0-2.4%), 22 episodes of alteration of mental status concerning for developing cerebral edema (11.5%, 95% CI 7.7-16.9%), 19 ICU transfers (10%, 95% CI 6.4-15.1%), and 7 episodes of hypoglycemia (3.7%, 95% CI 1.6-7.5%). ICU transfer was associated lower initial pH (7.03±0.06 vs. 7.07±0.07, p<0.05), increased length of stay (3.0±0.8 vs. 2.2±0.9days, p<0.05), and increased cost of hospitalization (mean±SD $8,073±2,042 vs. $5,217±1,697, p<0.05). The majority of children with severe DKA without alteration in mental status can be managed safely on a medical unit. Implementing a pH cutoff may identify high-risk patients that require ICU level of care.

Out-of-hours versus in-hours delivery of antenatally diagnosed transposition of the great arteries: outcomes from a United Kingdom Tertiary Centre.

To study the impact of out-of-hours delivery on outcome for neonates with antenatally diagnosed transposition of the great arteries. Tertiary paediatric cardiology centre (Yorkshire, United Kingdom), with co-located tertiary neonatal unit. Neonates with antenatally diagnosed simple transposition of the great arteries delivered out-of-hours (Monday to Friday 17:00-08:00 and weekends) versus in-hours between 2015 and 2020. The primary outcome was survival to hospital discharge. Secondary outcomes included neurological morbidity, length of stay, and time to balloon atrial septostomy. Of 51 neonates, 38 (75%) were delivered out-of-hours. All neonates born in the tertiary centre survived to discharge. Time to balloon atrial septostomy was slightly longer for out-of-hours deliveries compared to in-hours (median 130 versus 93 mins, p = 0.33). Neurological morbidity occurred for nine (24%) patients in the out-of-hours group and one (8%) in-hours (OR 3.72, 95% CI: 0.42-32.71, p = 0.24). Length of stay was also similar (18.5 versus 17.3 days, p = 0.59). Antenatal diagnosis of a restrictive atrial septum was associated with a lower initial pH (7.03 versus 7.13; CI: 0.03-0.17, p = 0.01), longer length of stay (22.6 versus 17.3 days; CI: 0.37-10.17, p = 0.04), and increased neurological morbidity (44% versus 14%; OR 4.80, CI 1.00-23.15, p = 0.05). A further three neonates were delivered in surrounding hospitals, with a mortality of 67% (versus 0 in tertiary centre; OR 172, CI 5-5371, p = 0.003). Neonates with antenatally diagnosed transposition of the great arteries have similar outcomes when delivered out-of-hours versus in-hours. Antenatal diagnosis of restrictive atrial septum is a significant predictor of worse outcomes. In our region, delivery outside the tertiary cardiac centre had a significantly higher risk of mortality.

Potential mechanisms contributing to the high cadmium removal efficiency from contaminated soil by using effective microorganisms as novel electrolyte in electrokinetic remediation applications

In this study, we tested the ability of a solution of effective microorganisms (EM) to remove cadmium from soil. Experimental results revealed that EM had an overall cadmium removal efficiency of 90.5% after 7 days of electrokinetic (EK) treatment. During EK treatment, EM exhibited a low initial pH of 3.6 and a high conductivity of 7.0 mS/m; therefore, they reduced the pH of the anode after an electric field was applied. EM had a surface tension of 50.3 dyne/cm and exhibited biosurfactant property in the EK experiments. The cadmium removal efficiency of EM in soil was compared with that of tap water, citric acid, and ethylenediaminetetraacetic acid (EDTA). The results revealed that after 7 days of EK treatment, EM had a higher cadmium removal efficiency than did citric acid (72.3%), EDTA (75.4%), and tap water (21.7%). This result can be partly attributed to the biosurfactant property of EM, which enables them to penetrate deeply into the soil matrix and thus dissolve a high quantity of pollutants. Overall, the results of this study indicate that EM can serve as an economic and efficient biosurfactant for removing cadmium from soil in EK applications.

Acetate improves catalytic performance for rapid removal of Cr(VI) by sodium borohydride in aqueous environments

An efficient method of remediating Cr(VI) involves the conversion of Cr(VI) to Cr(III) using sodium borohydride (NaBH4). However, information regarding the role of organic substances in Cr(VI) remediation is limited. As such, in this study, we aimed to evaluate the role of common low-molecular-weight acetate in the rapid chemical reduction of Cr(VI) by NaBH4 and subsequent total chromium (TCr) removal. The results showed that acetate promoted the transformation of high-concentration Cr(VI) to Cr(III) by NaBH4. The presence of 0–4 mM acetate did not affect the subsequent precipitation of Cr(III). In the presence of 4 mM acetate, Cr(VI) conversion was 99.03%, and subsequent TCr removal was 95.87% within 15 min without adding precipitant. The addition of acetate reduced the requirement for a low initial pH to achieve high Cr(VI) reduction efficiency. In particular, in the presence of 10 mM acetate, the conversion of 100 mg/L Cr(VI) by NaBH4 at an initial pH of 4 was 99.26% compared with 36.89% in the absence of acetate. Regarding the promotion mechanism of acetate for the reduction of Cr(VI) by NaBH4, we did not observe direct electron transfer from acetate to Cr(VI) at the origin of the reduction, but the reduction of Cr(VI) was promoted by inhibiting the production of OH– through buffering. Cr in HCrO4- was the favorable site for nucleophilic reaction, which could be attacked by H- from BH4-. According to the results of qualitative and semiquantitative XPS, Fourier transform infrared spectroscopy, and elemental analyses of sediments, a small amount of Cr(VI) and approximately 3% of acetate was removed through precipitation adsorption by the precipitated Cr(III). This novel acetate–Cr(VI)–NaBH4 remediation technology, which is simple and easy to use, improves the removal of high-concentration Cr(VI) from wastewater.

Enhanced selective nitrate-to-nitrogen reduction by aerosol-assisted iron-carbon composites: Insights into the key factors.

In this study, an aerosol-assisted Fe0/C (carbon supported zero-valent iron) composite was prepared and evaluated, which could effectively remove nitrate and exhibit high nitrogen selectivity. The results show that the selectivity of nitrogen for freshly prepared Fe0/C composites could reach 52.2% when pH at 7, compared to that of 7.7% for traditional nZVI. Meanwhile, the removal efficiency of nitrate was slightly increased from 63.5% to 69.9%. Furthermore, a variety of methods such as SEM, TEM, XRD, XPS, BET, FTIR and TGA were used to characterize the Fe0/C composites before and after reaction. Hence, the following key factors were determined for the effective conversion from nitrate to nitrogen: the surface of zero valent iron particle should be protected from oxidation and its genuine characteristics are well retained; the reaction should be controlled under an anaerobic condition; and the carbon as the carrier to support iron particles is very important; lower initial pH favors nitrogen generation. Various materials including aged Fe0/C composites, Fe0/SiO2 (SiO2 supported zero-valent iron) composites and nZVI particles in the deoxygenated and oxygenated systems were assessed for comparison.