Abstract ：

In this study, a compressive strength prediction model for Magnesium Phosphate Cement containing solid waste materials (SW-MPC) was developed using machine learning (ML) techniques. Firstly, a database of SW-MPC compressive strength was established through the selection of solid waste materials based on their chemical compositions. Subsequently, various ML algorithms were employed to construct predictive models for SW-MPC compressive strength, and the predictive accuracy of these models was compared. Furthermore, Shapley Additive Explanations (SHAP) analysis was utilized to assess the impact of various parameters on SW-MPC compressive strength. The results revealed that the Extreme Gradient Boosting (XGB) model exhibited the highest predictive accuracy and generalization ability. Among numerous feature parameters, the curing age (Age) and phosphate type (Type_PO4) were identified as the most critical factors influencing SW-MPC compressive strength. SW-MPC compressive strength exhibited a positive correlation with the Si content (Con_Si) and Al content (Con_Al) in the solid waste materials, while it generally displayed a negative correlation with Fe content (Con_Fe). The optimal Magnesium-to-Phosphorus ratio (M/P) for SW-MPC preparation ranged from 4 to 6. Furthermore, the influence of the dosage of solid waste materials (Per_sw) on the compressive strength of SW-MPC was complex, with the optimal content being around 10% and 35%. This complexity arose from the significant impact of the interactive effects between the content of different elements in solid waste materials and Per_sw on the compressive strength of SW-MPC.

Keyword ：

Magnesium phosphate cement Solid waste materials Compressive strength prediction Machine learning

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Abstract ：

Non-metallic atom doping is a good strategy to promote the cathode performance in the electro-Fenton process. Therefore, a mixed-valence copper (I and II) phosphate (Cu2PO4) catalyst on P-doped etched graphite felt (EGF), with a strip-groove rough surface, was prepared in this study. The P-doped Cu2PO4/EGF electrode completely removed sulfamethoxazole (SMX) from contaminated water within 90 min over a wide pH range of 5.6-9 and removed 99.6% of SMX at pH 11. Quenching experiments showed that the main reactive oxygen species (ROS) was center dot O-2(-). According to density functional theory calculations, the adsorption reaction energy (EP = 2.149) of P atoms doped on the EGF surface was lower than that of pyrrolic nitrogen atoms (EN = 0.434), indicating that they were more conducive to oxygen adsorption. Finally, we investigated the mechanism of P-doped Cu2PO4/ EGF adsorption and the catalytic production of center dot O-2(-) from O-2. Four main degradation pathways were identified based on the intermediates identified during degradation. Toxicity analysis of the intermediates showed that electro-Fenton degradation reduced the ecotoxicity of SMX. The enhanced electrocatalytic activity obtained by P doping of heterogeneous catalysts provides a new method for preparing efficient and stable composite electrodes for pollutant degradation.

Keyword ：

Superoxide anion radical Phosphorus doped electrode Degradation pathways Cu2PO4 Etched graphite felt

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Abstract ：

This study first systematically investigated selective Li+ extraction from Mg2+-rich brines with Na+ and K+ using ionic liquid (IL) based synergistic extractant (SE) systems from molecular mechanisms to extraction performances. The ternary combination 1-allyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([AMIM] [Tf2N]), tri-iso-butyl phosphate (TIBP) and dichloromethane (DCM), i.e., [AMIM][Tf2N]-TIBP-DCM was selected as a suitable SE from the diverse organic phosphorus ligands, ILs and diluents. The single-stage Li+ extraction efficiency was as high as 96.87%, and selectivities of beta Li+/Mg2+, beta Li+/Na+, and beta Li+/K+were up to 1161.94, 76.74, and 1263.46, respectively. It was found that Li+ is extracted from the aqueous phase to organic phase in Li+-4TIBP[Tf2N] complex. The molecular-level mechanism was identified as the multi-type interaction formed between metal ions and [AMIM][Tf2N]-TIBP to destroy the hydration of metal ions through quantum chemical (QC) calculations. The work proposes valuable theoretical guidance to develop novel IL-related SE systems for the high-efficiency Li+ extraction from salt lake brines.

Keyword ：

Extraction of lithium Quantum chemical calculation Synergistic extractant Ionic liquid Magnesium -rich brine Molecular mechanism

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Abstract ：

The stringent effluent quality standards in wastewater treatment plants (WWTPs) can effectively mitigate environmental issues such as eutrophication by reducing the discharge of nutrients into water environments. However, the current wastewater treatment process often struggles to achieve advanced nutrient removal while also saving energy and reducing carbon consumption. The first full-scale anaerobic/aerobic/anoxic (AOA) system was established with a wastewater treatment scale of 40,000 m3/d. Over one year of operation, the average TN and TP concentration in the effluent of 7.53 +/- 0.81 and 0.37 +/- 0.05 mg/L was achieved in low TN/COD (C/ N) ratio (average 5) wastewater treatment. The post-anoxic zones fully utilized the internal carbon source stored in pre-anaerobic zones, removing 41.29 % of TN and 36.25 % of TP. Intracellular glycogen (Gly) and proteins in extracellular polymeric substances (EPS) served as potential drivers for post-anoxic denitrification and phosphorus uptake. The sludge fermentation process was enhanced by the long anoxic hydraulic retention time (HRT) of the AOA system. The relative abundance of fermentative bacteria was 31.66 - 55.83 %, and their fermentation metabolites can provide additional substrates and energy for nutrient removal. The development and utilization of internal carbon sources in the AOA system benefited from reducing excess sludge production, energy conservation, and advanced nutrient removal under carbon-limited. The successful full-scale validation of the AOA process provided a potentially transformative technology with wide applicability to WWTPs.

Keyword ：

Advanced nitrogen removal Anaerobic/aerobic/anoxic Internal carbon sources Wastewater treatment Energy saving Full-scale

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Abstract ：

Conventional biological nutrient removal processes rely on external aeration and produce significant carbon dioxide (CO2) emissions. This study constructed a phototrophic simultaneous nitrification-denitrification phosphorus removal (P-SNDPR) system to treat low carbon to nitrogen (C/N) ratios wastewater and investigated the impact of sludge retention time (SRT) on nutrient removal performance, nitrogen conversion pathway, and microbial structure. Results showed that the P-SNDPR system at SRT of 15 days had the highest nutrient removal capacity, achieving over 85% and 98% removal of nitrogen and phosphorus, respectively, meanwhile maintaining minimal CO2 emissions. Nitrogen removal was mainly through assimilation at SRTs of 5 and 10 days, and nitrification-denitrification at SRTs of 15 and 20 days. Stable partial nitrification was facilitated by photoinhibition and low DO levels. Flow cytometry sorting technique results revealed SRT drove community structural changes in translational activity (BONCAT+) microbes, where BONCAT+ microbes were mainly simultaneous nitrogen and phosphorus removal bacteria (Candidatus Accumulibacter), denitrifying bacteria (Candidatus Competibacter and Plasticicumulans), ammonia-oxidizing bacteria (Nitrosomonas), and microalgae (Chlorella and Dictyosphaerium). The P-SNDPR system represents a novel, carbon-neutral process for efficient nutrient removal from low C/N ratio wastewater without aeration and external carbon source additions.

Keyword ：

sludge retention time flow cytometry sorting microalgal-bacterial systems translationactive low carbon to nitrogen ratio wastewater

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Abstract ：

Removing nitrogen and phosphorus from low ratio of chemical oxygen demand to total nitrogen and temperature municipal wastewater stays a challenge. In this study, a pilot-scale anaerobic/aerobic/anoxic sequencing batch reactor (A/O/A-SBR) system first treated 15 m 3 /d actual municipal wastewater at 8.1 - 26.4 degrees C for 224 days. At the temperature of 15.7 degrees C, total nitrogen in influent and effluent were 45.5 and 10.9 mg/L, and phosphorus in influent and effluent were 3.9 and 0.1 mg/L. 16 s RNA sequencing results showed the relative abundance of Competibacter and Tetrasphaera raised to 1.25 % and 1.52 %. The strategy of excessive, no and normal sludge discharge enriched and balanced the functional bacteria, achieving an endogenous denitrification ratio more than 43.3 %. Sludge reduction and short aerobic time were beneficial to energy saving contrast with a Beijing municipal wastewater treatment. This study has significant implications for the practical application of the AOASBR process.

Keyword ：

Low temperature Biological nitrogen and phosphorus removal Efficient wastewater treatment Endogenous denitrification Save energy

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Abstract ：

The two -sludge anoxic dephosphation (DEPHANOX) process frequently encounters the challenge of elevated effluent ammonia levels in practical applications. In this study, the anaerobic ammonium oxidation (anammox) biofilm was introduced into the DEPHANOX system, transforming it into a three -sludge system, enabling synchronous nitrogen and phosphorus elimination, particularly targeting ammonia. Despite a chemical oxygen demand/total nitrogen ratio of 4.3 +/- 0.8 in the actual municipal wastewater and 4.5 h of aeration, the effluent total nitrogen was 13.7 mg/L, lower than the parallel wastewater treatment plant. Additionally, the effluent ammonia reduced to 5.1 +/- 2.5 mg/L. Notably, denitrifying phosphorus removal and anammox were coupled in the anoxic zone, yielding 74.5 % nitrogen and 87.8 % phosphorus removal. 16S rRNA gene sequencing identified denitrifying phosphorus -accumulating organisms primarily in floc sludge (Saprospiraceae 7.07 %, Anaerolineaceae 1.95 %, Tetrasphaera 1.57 %), while anammox bacteria inhabited the biofilm (Candidatus Brocadia 4.00 %). This study presents a novel process for efficiently treating municipal wastewater.

Keyword ：

Partial denitrification Anammox Biological nutrient removal Biofilm

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Abstract ：

Effective retention of anammox bacteria (AnAOB) is the prerequisite for the application of anammox process, especially in treating low-strength wastewater. The employment of anammox granules coupled with phosphorus minerals has gained extensive attention as retaining biomass. To achieve the stability of mineralized anammox system for low-strength wastewater treatment, two switching strategies (cascade strategy and plunging strategy) were compared in terms of nitrogen removal performance, physicochemical properties and microbial community. Results showed cascade strategy significantly implemented the nitrogen removal rate of 0.86 +/- 0.05 kg N/ m3/d at hydraulic retention time of 1.6 h, with higher phosphorus removal via the hydroxyapatite formation. The cross-section observation indicated mineralized anammox granules exhibited a unique spatially heterogeneous structure with distinct zoning. Moreover, the granules displayed dense structure, excellent settleability, superior mechanical strength and outstanding biomass retention based on cascade strategy. Microbial analysis revealed the dominant populations were shifted from Ca. Kuenenia to Ca. Brocadia after switching to low-strength conditions. Further investigation is warranted to explore effective methods for phosphorus recovery from hydroxyapatite. Overall, the study provided a reference for promoting and understanding the synergistic nitrogen removal and phosphorus recovery in actual applications.

Keyword ：

Low-strength wastewater Mineralized anammox granule Cascade strategy Microbial succession Spatial distribution

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Due to their novel optical and optoelectronic properties, 2D materials have received increasing interest for optoelectronics applications. However, when the width of the channel layer decreases to the nanoscale, the properties of 2D materials can be seriously influenced due to the boundary defects and the approximation of physical dimensions and mean free path of the electron. That brings many challenges to developing novel electronics. Hence, researchers began to maintain their focus on 1D semiconductors without boundary defects and surfaces. Herein, fibrous phosphorus, another Quasi-1D layered semiconducting phosphorus allotrope with air-stable low symmetry, is reported. We found the in-plane anisotropic Raman response and excitation and exciton emission at room temperature. Moreover, the raw materials of fibrous phosphorus are nontoxic and abundant on the earth. These excellent properties will make it a highly competitive material for future applications in the optoelectronic area.

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Abstract ：

Photocatalytic hydrogen evolution (PHE) from water splitting is a promising technology for clean and renewable energy production. Elemental crystalline red phosphorus (CRP) is purposefully designed and developed for PHE reaction. However, the photocatalytic activity of CRP is limited by its intrinsic P vacancy (VP) defects, which lead to detrimental charge trapping at deep states and hence its severe recombination. To address this issue, a boron (B) incorporated CRP (B-CRP) photocatalyst is tailored, synthesized via a simple and mild boric acid-assisted hydrothermal strategy. The incorporation of B effectively fills the VP defects, reducing deep trap states (DTS) and introducing beneficial shallow trap states (STS) within the band structure of CRP. This defect engineering approach leads to enhanced photocatalytic activity, with B-CRP achieving a PHE rate of 1392 mu mol g-1 h-1, significantly outperforming most reported elemental photocatalysts in the literature. Density functional theory (DFT) simulations and ultrafast spectroscopy support the constructive role of B-dopant-induced STS in prolonging active charge carrier lifetimes, promoting more efficient photocatalytic reactions. The findings not only demonstrate the effectiveness of B-CRP as a photocatalyst but also highlight the usefulness of dopant-induced STS in advancing PHE technologies. A boron-incorporation-engineered crystalline red phosphorus system is demonstrated as a high-performance photocatalyst for visible-light hydrogen production from water splitting. Defect engineering via boron incorporation optimizes the trap states of crystalline red phosphorus, extending long-lived active charges and enhancing photocatalytic efficiency. This work provides insight into advanced photocatalytic material design for sustainable energy generation. image

Keyword ：

charge trapping red phosphorus vacancy defects photocatalytic hydrogen evolution boron incorporation

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