● A controlled-release fertilizer was developed based on chitosan biopolymer scaffold.

Fertilizer consumption is increasing drastically along with the rapid expansion of farming in response to the ever-growing population. However, a significant portion of the nutrients in traditional fertilizers is lost during leaching and runoff causing economic loss and environmental threats. Polymer-modified controlled-release fertilizers provide an opportunity for mitigating adverse environmental effects and increasing the profitability of crop production. Here, we present a cheap and easy-to-fabricate controlled-release fertilizer excipient based on hydrogels scaffolded by safe and biodegradable chitosan and montmorillonite (MMT) nanoclays. By introducing elastic and flexible physical crosslinking induced by 2-dimensional (2D) MMT nanoflakes into the chitosan hydrogel, highly swellable and degradable chitosan-MMT nanocomposites were fabricated. The addition of MMT into the chitosan hydrogels enhanced the total release of phosphorous (P) and potassium (K), from 22.0 % to 94.9 % and 9.6% to 31.4 %, respectively, compared to the pure chitosan gel. The chitosan-MMT nanocomposite hydrogel achieved a well-controlled overall fertilizer release in soil. A total of 55.3 % of loaded fertilizer was released over 15 d with a daily release of 2.8 %. For the traditional fertilizer podwer, 89.2 % of the fertilizer was washed out during the first irrigation under the same setup. In the meantime, the nanocomposites improved the water retention of the soil, thanks to its excellent water absorbency. Moreover, the chitosan-MMT nanocomposite hydrogels exhibited high degradation of 57 % after swelling in water for 20 d. Such highly degradable fertilizer excipient poses minimal threat to the long-term fertility of the soil. The engineered Chitosan-MMT biopolymer scaffold as a controlled-release fertilizer excipient provides a promising opportunity for advancing sustainable agriculture.

● p- CNB and IBP were selected, to explore factors determining ozonation outcomes.

● A machine learning model was used to identify lake nutrient pollution sources.

Effective control of lake eutrophication necessitates a full understanding of the complicated nitrogen and phosphorus pollution sources, for which mathematical modeling is commonly adopted. In contrast to the conventional knowledge-based models that usually perform poorly due to insufficient knowledge of pollutant geochemical cycling, we employed an ensemble machine learning (ML) model to identify the key nitrogen and phosphorus sources of lakes. Six ML models were developed based on 13 years of historical data of Lake Taihu’s water quality, environmental input, and meteorological conditions, among which the XGBoost model stood out as the best model for total nitrogen (TN) and total phosphorus (TP) prediction. The results suggest that the lake TN is mainly affected by the endogenous load and inflow river water quality, while the lake TP is predominantly from endogenous sources. The prediction of the lake TN and TP concentration changes in response to these key feature variations suggests that endogenous source control is a highly desirable option for lake eutrophication control. Finally, one-month-ahead prediction of lake TN and TP concentrations (R² of 0.85 and 0.95, respectively) was achieved based on this model with sliding time window lengths of 9 and 6 months, respectively. Our work demonstrates the great potential of using ensemble ML models for lake pollution source tracking and prediction, which may provide valuable references for early warning and rational control of lake eutrophication.

● This study systematically examined the relationship between groundwater Cd and UCL.

Cadmium (Cd) has received widespread attention owing to its persistent toxicity and non-degradability. Cd in the human body is mainly absorbed from the external environment and is usually assessed using urinary Cd. Hunan Province is the heartland of the Chinese non-ferrous mining area, where several serious Cd pollution events have occurred, including high levels of Cd in the urine of residents. However, the environmental factors influencing high urinary Cd levels (UCLs) in nearby residents remain unclear. Therefore, 211 nearby residents’ UCLs and the corresponding sociological characteristics from nine groundwater samples in this area were analyzed using statistical analysis models. Groundwater Cd concentration ranged from 0.02 to 1.15 μg/L, aligning with class III of the national standard; the range of UCL of nearby residents was 0.37–36.60 μg/L, exceeding the national guideline of 0–2.5 μg/L. Groundwater Cd levels were positively correlated with the UCL (P < 0.001, correlation coefficient 95 % CI = 9.68, R² = 0.06). In addition, sociological characteristics, such as smoking status and education level, also affect UCL. All results indicate that local governments should strengthen the prevention and abatement of groundwater Cd pollution. This study is the first to systematically evaluate the relationship between groundwater Cd and UCL using internal and external environmental exposure data. These findings provide essential bases for relevant departments to reduce Cd exposure in regions where the heavy metal industry is globally prevalent.

● Definition of emerging contaminants in drinking water is introduced.

Emerging contaminants (ECs) in drinking water pose threats to public health due to their environmental prevalence and potential toxicity. The occurrence of ECs in our drinking water supplies depends on their physicochemical properties, discharging rate, and susceptibility to removal by water treatment processes. Uncertain health effects of long-term exposure to ECs justify their regular monitoring in drinking water supplies. In this review article, we will summarize the current status and future opportunities of surface-enhanced Raman spectroscopy (SERS) for EC analysis in drinking water. Working principles of SERS are first introduced and a comparison of SERS and liquid chromatography-tandem mass spectrometry in terms of cost, time, sensitivity, and availability is made. Subsequently, we discuss the strategies for designing effective SERS sensors for EC analysis based on five categories—per- and polyfluoroalkyl substances, novel pesticides, pharmaceuticals, endocrine-disrupting chemicals, and microplastics. In addition to maximizing the intrinsic enhancement factors of SERS substrates, strategies to improve hot spot accessibilities to the targeting ECs are equally important. This is a review article focusing on SERS analysis of ECs in drinking water. The discussions are not only guided by numerous endeavors to advance SERS technology but also by the drinking water regulatory policy.

● Bimetallic oxide composite catalyst was designed for the urea-based SCR process.

As a promising option to provide gaseous NH₃ for SCR system, catalytic urea hydrolysis has aroused great attention, and improving surface area and activity of catalysis are the crucial issues to be solved for efficient urea hydrolysis. Therefore, a composite metal oxide (TiO₂@Al₂O₃) catalyst was prepared by a simple hydrothermal method, with mesoporous alumina (γ-Al₂O₃) as substrate. The results verify the mesoporous structure and submicron cluster of TiO₂@Al₂O₃, with exposed crystal faces of (101) and (400) for TiO₂ and γ-Al₂O₃, respectively. The electronegativity difference of Ti⁴⁺ and Al³⁺ changes the charge distribution scheme around the interface, which provides abundant acid/base sites to boost the urea hydrolysis. Consequently, for an optimal proportioning with nano TiO₂ content at 10 wt.%, the hydrolysis efficiency can reach up to 35.2 % at 100 °C in 2 h, increasing by ~7.1 % than that of the blank experiment. ¹³C NMR spectrum measurements provide the impossible intermediate species during urea hydrolysis. Theoretical calculations are performed to clarify the efficient H₂O decomposition at the interface of TiO₂@Al₂O₃. The result offers a favorable technology for energy-efficiency urea hydrolysis.

● A crosslinked polyaniline/carbon nanotube NF membrane was fabricated.

Nanofiltration (NF) has attracted increasing attention for wastewater treatment and potable water purification. However, the high-efficiency removal of micropollutants by NF membranes is a critical challenge. Owing to the adsorption and subsequent diffusion, some weakly charged or uncharged micropollutants, such as bisphenol A (BPA), can pass through NF membranes, resulting in low removal rates. Herein, an effective strategy is proposed to enhance the BPA removal efficiency of a crosslinked polyaniline/carbon nanotube NF membrane by coupling the membrane with electro-assistance. The membrane exhibited a 31.9% removal rate for 5 mg/L BPA with a permeance of 6.8 L/(m²·h·bar), while the removal rate was significantly improved to 98.1% after applying a voltage of 2.0 V to the membrane. Furthermore, when BPA coexisted with humic acid, the membrane maintained 94% removal of total organic carbon and nearly 100% removal of BPA at 2.0 V over the entire filtration period. Compared to continuous voltage applied to the membrane, an intermittent voltage (2.0 V for 0.5 h with an interval of 3.5 h) could achieve comparable BPA removal efficiency, because of the combined effect of membrane adsorption and subsequent electrochemical oxidation. Density functional theory calculations and BPA oxidation process analyses suggested that BPA was adsorbed by two main interactions: π–π and hydrogen-bond interactions. The adsorbed BPA was further electro-degraded into small organic acids or mineralized to CO₂ and H₂O. This work demonstrates that NF membranes coupled with electro-assistance are feasible for improving the removal of weakly charged or uncharged micropollutants.

● Salinity led to the elevation of NAR over 99.72%.

Biological treatment processes are critical for sewage purification, wherein microbial interactions are tightly associated with treatment performance. Previous studies have focused on assessing how environmental factors (such as salinity) affect the diversity and composition of the microbial community but ignore the connections among microorganisms. Here, we described the microbial interactions in response to elevated salinity in an activated sludge system by performing an association network analysis. It was found that higher salinity resulted in low microbial diversity, and small, complex, more competitive overall networks, leading to poor performance of the treatment process. Subnetworks of major phyla (Proteobacteria, Bacteroidetes, and Chloroflexi) and functional bacteria (such as AOB, NOB and denitrifiers) differed substantially under elevated salinity process. Compared with subnetworks of Nitrosomonadaceae, Nitrosomonas (AOB) made a greater contribution to nitrification under higher salinity (especially 3%) in the activated sludge system. Denitrifiers established more proportion of cooperative relationships with other bacteria to resist 3% salinity stress. Furthermore, identified keystone species playing crucial roles in maintaining process stability were dynamics and less abundant under salinity disturbance. Knowledge gleaned from this study deepened our understanding of microbial interaction in response to elevated salinity in activated sludge systems.

● Dredged river sediment was proved as a ceramic precursor rather than a solid waste.

Cd-bearing solid wastes are considered to be a serious threat to the environment, and effective strategies for their treatment are urgently needed. Ceramic sintering has been considered as a promising method for efficiently incorporating heavy metal-containing solid wastes into various ceramic products. Mineral-rich dredged river sediment, especially Al and Si-containing oxides, can be treated as alternative ceramic precursors rather than being disposed of as solid wastes. To examine the feasibility of using waste sediment for Cd stabilization and the phase transition mechanisms, this study conducted a sintering scheme for the mixtures of CdO and dredged river sediment with different (Al+Si):Cd mole ratios. Detailed investigations have been performed on phases transformation, Cd incorporation mechanisms, elemental distribution, and leaching behaviors of the sintered products. Results showed that Cd incorporation and transformation in the sintered products were influenced by the mole ratio of (Al+Si):Cd. Among the high-Cd series ((Al+Si):Cd = 6:1), CdSiO₃, Cd₂SiO₄, CdAl₂(SiO₄)₂ and Cd₂Al₂Si₂O₉ were predominant Cd-containing product phases, while Cd₂Al₂Si₂O₉ was replaced by CdAl₄O₇ when the mole ratio of (Al+Si):Cd was 12:1 (low-Cd series). Cd was efficiently stabilized in both reaction series after being sintered at ≥ 900 °C, with < 5% leached ratio even after a prolonged leaching time, indicating excellent long-term Cd stabilization. This study demonstrated that both Cd-containing phases and the amorphous Al-/Si-containing matrices all played critical roles in Cd stabilization. A promising strategy can be proposed to simultaneously reuse the solid waste as ceramic precursors and stabilize heavy metals in the ceramic products.

● A single particle observation was conducted in a high traffic flow road environment.

A single particle aerosol mass spectrometer (SPAMS) was used to accurately quantify the contribution of vehicle non-exhaust emissions to particulate matter at typical road environment. The PM_2.5, black carbon, meteorological parameters and traffic flow were recorded during the test period. The daily trend for traffic flow and speed on TEDA Street showed obvious “M” and “W” characteristics. 6.3 million particles were captured via the SPAMS, including 1.3 million particles with positive and negative spectral map information. Heavy Metal, High molecular Organic Carbon, Organic Carbon, Mixed Carbon, Elemental Carbon, Rich Potassium, Levo-rotation Glucose, Rich Na, SiO₃ and other categories were analyzed. The particle number concentration measured by SPAMS showed a good linear correlation with the mass concentrations of PM_2.5 and BC, which indicates that the particulate matter captured by the SPAMS reflects the pollution level of fine particulate matter. EC, ECOC, OC, HM and crustal dust components were found to show high values from 7:00–9:00 AM, showing that these chemical components are directly or indirectly related to vehicle emissions. Based on the PMF model, 7 major factors are resolved. The relative contributions of each factor were determined: vehicle exhaust emission (44.8 %), coal-fired source (14.5 %), biomass combustion (12.2 %), crustal dust (9.4 %), ship emission (9.0 %), tires wear (6.6 %) and brake pads wear (3.5 %). The results show that the contribution of vehicle non-exhaust to particulate matter at roadside environment is approximately 10.1 %. Vehicle non-exhaust emissions are the focus of future research in the vehicle pollutant emission control field.

● Effect of composting approaches on dissolved organic matter (DOM).

As the most motive organic fraction in composting, dissolved organic matter (DOM) can contribute to the transfer and dispersal of pollutants and facilitate the global carbon cycle in aquatic ecosystems. However, it is still unclear how composting approaches and conditions influence the properties of compost-derived DOM. Further details on the shift of DOM character indexes are required. In this study, the change in properties of compost-derived DOM at different composting approaches and the effect of composting conditions on the DOM characteristics are summarized. Thereafter, the change in DOM character indexes’ in composting was comprehensively reviewed. Along with composting, the elements and spectral properties (chromophoric DOM (CDOM) and fluorescent DOM (FDOM)) were altered, size and hydrophobicity increased, and aromatic-C and electron transfer capacity were promoted. Finally, some prospects to improve this study were put forward. This paper should facilitate the people who have an interest in tracing the fate of DOM in composting.

● BACs were used in electrode material for both fixed and flowing electrodes.

Capacitive deionization (CDI) is a novel electrochemical water-treatment technology. The electrode material is an important factor in determining the ion separation efficiency. Activated carbon (AC) is extensively used as an electrode material; however, there are still many deficiencies in commercial AC. We adopted a simple processing method, ball milling, to produce ball milled AC (BAC) to improve the physical and electrochemical properties of the original AC and desalination efficiency. The BAC was characterized in detail and used for membrane capacitive deionization (MCDI) and flow-electrode capacitive deionization (FCDI) electrode materials. After ball milling, the BAC obtained excellent pore structures and favorable surfaces for ion adsorption, which reduced electron transfer resistance and ion migration resistance in the electrodes. The optimal ball-milling time was 10 h. However, the improved effects of BAC as fixed electrodes and flow electrodes are different and the related mechanisms are discussed in detail. The average salt adsorption rates (ASAR) of FCDI and MCDI were improved by 134% and 17%, respectively, and the energy-normalized removal salt (ENRS) were enhanced by 21% and 53%, respectively. We believe that simple, low-cost, and environmentally friendly BAC has great potential for practical engineering applications of FCDI and MCDI.