Low temperature severely inhibits microbial activity, making biological method inefficient for ammonium removal from wastewater. A zeolite biological fixed-bed (ZBFB) was successfully established for 6.0–8.0 °C low-strength ammonium wastewater treatment via adsorption-regeneration. Ion exchange was a remarkable alternative and zeolite was mostly applied. Nevertheless, insufficient zeolite bio-regeneration rate was the key obstacle for economically sustainable utilization. By adsorption, effluent NH₄⁺-N was around 1.5–2.5 mg/L. About 26% regeneration rate was obtained. With a ceramsite biological aerobic filter (CBAF) operated with ZBFB in series at the regeneration stage, the regeneration rate reached 95%, 3.5 times higher. Studies of alkalinity effects on bio-zeolite regeneration process indicated that Na₂CO₃ worked better than NaHCO₃. Greater amount and one dose mode of alkalinity addition, higher regeneration rate could be obtained. The bio-zeolite regeneration process followed pseudo first-order kinetics with K = 0.0629 h⁻¹. High-throughput sequencing analysis indicated the enriched nitrifying microorganisms in CBAF fully oxidized NH₄⁺-N in regeneration solution, which accelerated desorption and conversion of NH₄⁺-N by the circulation of regeneration solution between ZBFB and CBAF. The dynamic adsorption experiment proved that ZBFB-CBAF was feasible for cold low-strength ammonium wastewater treatment.

Uranium-contaminated wastewater associated with uranium (U) mining and processing inevitably releases into soil environment. In order to assess the risk of U wastewater contamination to groundwater through percolation, U adsorption and transport behavior in a typical red soil in South China was investigated through batch adsorption and column experiments, and initial pH and carbonate concentration were considered of the high-sulfate background electrolyte solution. Results demonstrated that U adsorption isotherms followed the Freundlich model. The adsorption of U to red soil significantly decreased with the decrease of the initial pH from 7 to 3 in the absence of carbonate, protonation-deprotonation reactions controlled the adsorption capacity, and lnCₛ had a linear relationship with the equilibrium pH (pHₑq). In the presence of carbonate, the adsorption was much greater than that in the absence of carbonate owing to the pHₑq values buffered by carbonate, but the adsorption decreased with the increase of the carbonate concentration from 3.5 to 6.5 mM. Additionally, the breakthrough curves (BTCs) obtained by column experiments showed that large numbers of H⁺ and CO₃²⁻ competed with the U species for adsorption sites, which resulted in BTC overshoot (C/C₀ > 1). Numerical simulation results indicated that the BTCs at initial pH 4 and 5 could be well simulated by two-site chemical non-equilibrium model (CNEM), whereas the BTCs of varying initial carbonate concentrations were suitable for one-site CNEM. The fractions of equilibrium adsorption sites (f) seemed to correlate with the fractions of positively charged complexes of U species in solution. The values of partition coefficients (kd′) were lower than those measured in batch adsorption experiments, but they had the same variation trend. The values of first-order rate coefficient (ω) for all BTCs were low, representing a relatively slow equilibrium between U in the liquid and solid phases. In conclusion, the mobility of U in the red soil increased with the decrease of the initial pH and with the increase of the initial carbonate concentrations.

The development of congenital heart disease (CHD) is a complicated process and affected by multiple environmental factors, as genetic factors, and the interactions among those factors. Previous studies have shown that intrauterine hypoxic environment exposure is a risk factor of CHD, but the genetic factors involved in the process are not clear. In this study, given that tetralogy of Fallot (TOF) is a CHD with hypoxemia as its primary pathophysiological manifestation, an in silico analysis was performed to reveal the relationship between potential target genes (miR-124) with the energy metabolism in non-syndromic TOF patients’ cardiomyocyte. Furthermore, the study investigated the correlation between the primary miR-124 (rs531564) polymorphism and CHD susceptibility in 432 sporadic patients and 450 controls from two different altitude provinces (city) in China. Our study indicated that the minor C allele of rs531564 correlated with reduced risk of CHD in the low altitude city. Besides, the C allele has elevated frequency in the high-altitude group. Therefore, our findings suggest that the minor C allele of rs531564 SNP may be involved in the reduction of the risk of CHD in a way that interacts with the intrauterine hypoxic environmental factors.

Carbon emissions in the power sector are an important part of China’s total carbon emissions and have a significant impact on whether China can achieve the 2030 carbon peak target. Based on the three perspectives of decomposition, decoupling, and prediction, this paper studies the feasibility of carbon emission peaks in eight major regional power sectors in China. First, the generalized Divisia index model (GDIM) is used to decompose the carbon emissions of the eight regional power sectors, and the driving factors and their effects on carbon emissions in the power sector of each region are compared. Then, the decoupling index based on the generalized Divisia index model (GDIM-D) is used to study the decoupling relationship between the carbon emissions of the eight regional power sectors and economic growth. Finally, the carbon emissions and decoupling indices of the power sector from 2017 to 2030 are predicted. The results show the following. First, the gross domestic product (GDP) and output scale are the main factors contributing to the carbon emissions of the eight regional power sectors. The carbon intensity of the power sector in GDP (C/G) and output carbon intensity(C/E) are the main factors that contribute to the reduction. Second, the carbon emissions of the southern coast, the middle Yellow River, and the Southwest peaked in 2013 and have been decoupled from economic growth, while those in the other regions have not peaked or decoupled. Third, if the carbon emissions of the power sector in the Northeast, northern coast, eastern coast, middle Yangtze River, and Northwest reach a peak in 2030, they will face many emission reduction pressures. This paper provides a reference for studying the carbon emissions of China’s regional power sectors and their relationship with economic growth and has important implications for peak carbon emissions at the national level.

Pig farming has a very strong economic importance in Brazil. The residues from this activity are applied to the soil because of their excellent characteristics as biofertilizers. The present study aimed at studying the estrone, 17β-estradiol, and estriol natural hormones, emerging contaminants present in this type of residue that are not mentioned in the current legislation. The characterization of the pig farming effluent presented high concentrations of hormones (mg L⁻¹). The objective was to apply the biosorbents to the removal of the hormones in batch systems directly in the manure heaps without affecting the potential of the effluent as a fertilizer. It was verified that the adsorption of hormones using the rice husk biomass in natura and soybean hull in natura, abundant alternative adsorbents, presented a good capacity of removal of hormones. The presence of the organic materials (rice husk and soybean hull) caused few alterations in the biofertilizer characteristics, demonstrating that these adsorbents present a potential of application in batch treatment systems, with possible applications related to pig farming effluents containing natural hormones.

It aimed to investigate and evaluate the soil amelioration process of bauxite residues with the amendments of organic materials from different sources. Wheat straw, poultry manure compost, and biosolids were chosen as the added organic materials. A series of essential soil properties were analyzed to evaluate the effects of organic materials on the soil amelioration of bauxite residue. The results indicated that organic amendments could obviously improve the texture of bauxite residues by increasing large aggregates contents, and elevating its organic matter content and fertility level (such as TN and TP). At the same time, organic additions were effective in reducing bauxite residues’ salinity as pH, electrical conductivity and sodium content were obviously decreased in all rehabilitated treatments in comparison with control treatment. These improvements created sufficient conditions for a quick recovery of microbial communities in bauxite residues matrix. The maximum microbial biomass C increased to 0.642 g-C·kg⁻¹, and the activities of urease, catalase, and invertase were massively elevated, especially for those after a year of rehabilitation, although alkali-phosphatase was kept a less level compared with other biological parameters. The further principal analysis and cluster analysis indicated that after 1 year of organic amendment, the improved bauxite residues matrix was very close to the reference soil based on the measured soil microbial properties. All the results suggested that organic amendment is an effective way to stimulate the soil amelioration of bauxite residues, and among the three amended organic materials, wheat straw and biosolid were better in improving the abiotic environmental conditions as well as biotic function recovery in soil amelioration of bauxite residue.

Anammox process is considered as a promising technology for removing total nitrogen from low-strength ammonium and phenol-containing wastewater. However, it is still a challenge for the anammox process to treat high-strength ammonium and phenol-containing wastewater. A completely separated partial nitritation and anammox (CSPN/A) process was developed to remove total nitrogen from high-strength phenol-containing wastewater. About 92% of COD, 100% of phenol, and 82.4% of total nitrogen were successfully removed at a NH₄⁺-N concentration of 200 mg L⁻¹ with a phenol/NH₄⁺-N mass ratio of 0.5 in the CSPN/A process. Furthermore, a shock loading of 300 mg phenol L⁻¹ with a phenol/NH₄⁺-N mass ratio of 1.5 led to a complete failure of partial nitritation, but the performance was rapidly recovered by the increase of NH₄⁺-N concentration. Although the activities of ammonium-oxidizing bacteria and anammox bacteria were severely inhibited at a phenol/NH₄⁺-N mass ratio of 1.5, the enrichment of efficient phenol degraders in the CSPN stage could strengthen the performance robustness of partial nitritation and anammox process. Therefore, this study presented a new insight on the feasibility of the anammox process for treating high-strength ammonium and phenol-containing wastewater.

In this work, TiO₂ (B) nano-belts were synthesized by hydrothermal method under stirring, and static conditions and preparation conditions were optimized. The prepared materials were characterized by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), photoluminescence spectroscopy (PL), and N₂ adsorption/desorption measurement. The photocatalytic performance was evaluated by removing synthetic estrogen 17α-ethynylestradiol (EE2), which is the most potent endocrine-disrupting chemical. The results show that the TiO₂ nano-belt possesses pure metastable monoclinic TiO₂ (B) and has uniform nano-belt shape with 80~120-nm diameters and 62.904 m² g⁻¹ of specific surface area. Under the best optimal preparation conditions (0.5 g P25, 20 mL 10 mol L⁻¹ NaOH, hydrothermal temperature 180 °C for 18 h under stirring, 400 °C calcination for 2 h), the TiO₂ (B) has better catalytic activity with 100.00% removal rate towards 3 mg L⁻¹ EE2 in 120 min. The removal rates of EE2 over catalyst which was prepared under static condition and P25 are 74.66% and 70.71%, respectively. The photocatalytic degradation rate constant of TiO₂ (B) prepared under stirring condition (0.0379 min⁻¹) is 4.51 times and 8.42 times than those of TiO₂ prepared under static condition (0.0084 min⁻¹) and P25 (0.0045 min⁻¹). The excellent photocatalytic activity is mainly ascribed to longer one-dimensional nano-belt structure and effective suppression of photo-produced electron-hole.

Lichen secondary metabolites are known to be associated with heavy metal uptake and tolerance in lichens. Understanding the relationship between their secondary metabolites and heavy metals in them is important for clarifying the mechanisms of their heavy metal accumulation and tolerance. To determine the relationships between the concentrations of secondary metabolites and Cu in the Cu-hyperaccumulator lichen Stereocaulon japonicum and to clarify its response to Cu, we collected Cu-contaminated and uncontaminated samples of the lichen and determined relative concentrations of secondary metabolites and concentrations of Cu, K, glucose, and sugar alcohols in them. We found significant negative correlations between the relative concentrations of secondary metabolites—atranorin and stictic acid—and the concentration of Cu. These negative correlations can be interpreted in one of two ways: (a) S. japonicum itself reduced the relative concentrations of secondary metabolites in response to the increase of Cu concentration or (b) its carbon and energy metabolism was damaged by Cu stress, resulting in the reduction of the relative concentrations of secondary metabolites. The analysis of K, glucose, and sugar alcohols showed no effect of Cu on these concentrations, which means that the carbon and energy metabolism was not damaged by Cu stress. Therefore, the negative correlations can be interpreted that S. japonicum itself reduced the relative concentrations of secondary metabolites with the increase of Cu concentration. These findings provide a deeper understanding of the response of secondary metabolites to Cu in the lichen.

The electrochemical conversion of inorganic nitrogen forms (i.e., NO₃⁻-N, NO₂⁻-N, and NH₄⁺-N) to N₂ was studied using Ti as cathode and Ti/PbO₂ as anode in the simulated wastewater. According to linear sweep voltammetry, nitric nitrogen was effectively converted to N₂ on Ti cathode at the working potential more negative than − 1.1 V (vs. SCE). Ti/PbO₂ anode had the working potential of + 0.8 V (vs. SCE) for NH₄⁺-N converted to N₂. The apparent rate constants of NO₃⁻-N to NO₂⁻-N and NO₂⁻-N to N₂ were 2.46 × 10⁻² min⁻¹ and 4.03 × 10⁻² min⁻¹, respectively. The kinetic analyses revealed that the reduction of NO₃⁻-N was a two-step process, and NO₂⁻-N was an unstable intermediate, which could be easily oxidized to NO₃⁻-N or reduced to NH₄⁺-N. The majority of NH₄⁺-N could be effectively converted to N₂ on Ti/PbO₂ anode with the apparent rate constants of 5.12 × 10⁻² min⁻¹. The dual-chamber (DC) reactor with circulation was used in the batch electrolysis of simulated and actual wastewater. The results verified the pathways of NH₄⁺-N oxidation and NO₃⁻-N reduction and achieved high conversion rate of total nitrogen (TN) to N₂.