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[Display omitted] By introducing a minute quantity of phytate ammonium into the conventional dilute zinc sulfate electrolyte, a static physical barrier is established by the phytic anion. Simultaneously, a dynamic electrostatic shield layer collaborates, yielding superior electrochemical performance. This addition facilitates an accelerated de-solvation process, effectively suppressing the so-called "tip effect" and mitigating dendrite growth. • Developed facile and effective additives for aqueous zinc-ion batteries. • Utilized both cation and anion for a multi-functional additive. • Physical barrier and dynamic electrostatic-field shield layer enhance performance. • Realized a dual protection mechanism for high performance. Corrosion and the formation of by-products resulting from parasitic side reactions, as well as random dendrite growth, pose significant challenges for aqueous zinc-ion batteries (AZIBs). In this study, phytate ammonium is introduced into the traditional dilute Zinc sulfate electrolyte as a multi-functional additive. Leveraging the inherent zincophilic nature of the phytic anion, a protective layer is formed on the surface of the zinc anode. This layer can effectively manipulate the deposition process, mitigate parasitic reactions, and reduce the accumulation of detrimental by-products. Additionally, the competitive deposition between dissociated ammonium ions and Zn2+ promotes uniform deposition, thereby alleviating dendrite growth. Consequently, the modified electrolyte with a lower volume addition exhibits superior performance. The zinc symmetric battery demonstrates much more reversible plating/stripping, sustaining over 2000 h at 5 mA cm−2 and 1 mA h cm−2. A high average deposition/stripping efficiency of 99.83 % is achieved, indicating the significant boosting effect and practical potential of our strategy for high-performance aqueous zinc-ion batteries. [ABSTRACT FROM AUTHOR]

• Bipolar membrane ED was used for nutrient recovery from AD dewatering sidestream. • Concentrated acid and base streams containing separated nutrients were produced. • Ammonia was recovered using a produced acid solution by membrane stripping. • Phosphate was recovery as struvite or hydroxyapatite by chemical precipitation. • Nutrient recovery was achieved with minimized chemical and energy inputs. Anaerobic digestion (AD) offers an efficient means for treating sludge generated in wastewater treatment plants (WWTPs), but nutrient-rich AD dewatering sidestream contributes as much as 30 % of the overall nutrient loading of WWTPs. Several electrochemical approaches are being developed as a sidestream treatment strategy to prevent return of nutrients to WWTP headworks and recover them for fertilizer production. One such method is to produce acids and bases, essential chemicals necessary to facilitate nutrient recovery, using bipolar membrane electrodialysis (BMED). In this study we show simultaneous separation of nutrients and production of acid/base streams with an additional consideration for increasing the concentration of ammonium and phosphate in the final product stream by systematically altering compartment flow rates and hence the retention time of each stream. Using a three-compartment BMED system with a synthetic sidestream containing 50 mM NH 3 -N and 2 mM PO 4 -P, we achieved up to 80 % ammonia removal (via a cation exchange membrane) and up to 60 % phosphate removal (via an anion exchange membrane) at a productivity of 34.2 L m−2 h−1. Separated ammonia was recovered (>90 %) in a subsequent membrane contactor (MC) that was fed with acid and base streams produced by the BMED unit. A phosphate recovery > 80 % was achieved by chemical precipitation (CP). In a combined BMED-MC-CP process, the concentrated final product contained 333.9 mM NH 3 -N and 3.1 mM PO 4 -P with an energy consumption of 8.9 kWh kg−1 N recovered. These results illustrate that the BMED-based treatment train is a promising strategy for nutrient recovery from AD dewatering sidestream. [ABSTRACT FROM AUTHOR]

The QCD36A 1-1 350 shows excellent photocatalytic activity for H 2 O 2 production under visible light irradiation. [Display omitted] • A quaternary ammonium cyclodextrin polymeric photocatalyst QCD36A 1-1 350 is successfully synthesized. • The quaternary ammonium group in the QCD36A 1-1 350 structure broadened the absorption of visible light. • The introduction of quaternary ammonium groups can facilitate efficient charge transfer, speed up the 2e- ORR process. • A photocatalytic H 2 O 2 yield of 2.51 mmol g−1h−1 was achieved in purified water without an electron donor or aeration. A photocatalytic system can be used to efficiently produce hydrogen peroxide (H 2 O 2) without introducing a sacrificial agent or oxygen (O 2). This system has practical application potential but remains challenging to implement. To increase the H 2 O 2 yield of this system, a quaternary ammonium cyclodextrin polymeric photocatalyst QCD36A 1-1 350 is successfully synthesized using quaternization modification and low-temperature polycondensation. The photocatalyst is used to produce H 2 O 2 from pure water and air by the one-step two electron oxygen reduction reaction. Under irradiation by visible light, QCD36A 1-1 350 produces a higher H 2 O 2 yield (of up to 2.51 mmol g−1h−1) than unquaternized polymers and reported metal-free catalysts under similar conditions. Experimental and theoretical studies clearly show that the introduction of quaternary ammonium groups can effectively broaden the visible light absorption of polymer catalysts, while increasing the hydrophilicity, charge transfer efficiency and surface stability. The practicability of efficient photocatalytic production of H 2 O 2 is realized by increasing the activity and selectivity of the polymer photocatalyst. [ABSTRACT FROM AUTHOR]

[Display omitted] • UDB and DB at different pyrolysis temperatures played contrasting roles. • DB800-amended group displayed superior nitrogen removal performance. • DB at lower pyrolysis temperature imposed suppression. • Properties of dissolved organic matter released by DB were tracked at molecular level. Biochar has attracted increasingly attention in the biological wastewater treatment owing to its unique environmental behavior. However, the differential effects of undissolved and dissolved fractions of biochar (hereafter named as UDB and DB, respectively) on the anaerobic ammonium oxidation (anammox) process remain unclear. The study evaluated the nitrogen removal performance of anammox system in response to UDB and DB prepared at different pyrolysis temperatures (300 °C, 550 °C and 800 °C). The DB800-amended group displayed superior nitrogen removal performance with the total nitrogen removal efficiency (TNRE) of 92.8 ± 1.4 %. Compared with CK, TNRE was changed by +5.0 % (UDB300), +0.4 % (UDB550) and −22.3 % (UDB800) for UDB-amended groups, and by −16.0 % (DB300), −9.4 % (DB550), and +9.2 % (DB800) for DB-amended groups, respectively. The differences were closely related to the physicochemical properties of UDB and DB. Particularly, dissolved organic matter released by DB were tracked at molecular level, which revealed that CHO occupied the highest proportion of 70.3 % and lignin-like and carboxylic rich alicyclic molecules were dominant in DB800. This study would facilitate the understanding of the differences between the nitrogen removal performance of UDB and DB-amended anammox, thus providing deeper insights for the comprehensive assessment of the impacts of biochar on the anammox process. [ABSTRACT FROM AUTHOR]

[Display omitted] • Micro-oxygen combined with applied voltage promote total nitrogen removal. • Electrode regulates the spatial distribution of functional microorganisms. • Applied voltage regulates function gene abundance and enzyme activity. • Hydroxylamine oxidation peaks and up-regulation hao gene are demonstrated. Anodic ammonium oxidation catalyzed by microorganisms holds great potential as an effective anaerobic approach for ammonium and total nitrogen removal. However, the application of this approach is constrained by a low rate of ammonium oxidation, limiting the efficiency of total nitrogen removal. To overcome this limitation, a small amount of oxygen was introduced into a single-chamber microbial electrolysis cell to initiate the production of hydroxylamine through ammonium oxidation. Enhanced efficiency of overall nitrogen removal was obtained by the combined regulation of micro-oxygen and microbial electrode catalysis for ammonium oxidation and denitrification. According to the ammonium oxidation amount, the total oxidized nitrogen removal efficiency reached 67.87 ± 0.25 % and total nitrogen removal amount was 202.9 ± 0.5 mg/L, showing a high performance for treating high ammonium-contained wastewater. The oxidation peaks of hydroxylamine were determined at 0.43 V (vs. Ag/AgCl) for revealing the possible process of anodic hydroxylamine oxidation coupling to cathodic denitrification. In addition, microbial community analysis revealed that increasing the applied voltage regulated the abundance of nitrifying and denitrifying functional microbial communities both in the solution and on electrodes, and the key functional genes including hydroxylamine oxidation (hao), nitrate reduction (narG , narH , narI , napA , napB), nitrite reduce (nirK, nirS), and nitric oxide reduce (norB , norC), increased significantly at the applied voltage of 0.9 V, which accompanied by an obvious enhancement of enzyme activity compared to anaerobic and open circuit voltage. This work revealed the enhanced performance and mechanism on synergistic regulation by micro-oxygen and applied voltage for ammonium oxidation and denitrification, and provided new insights and feasible enhancing measures for treating high ammonium-nitrogen wastewater with low C/N ratio. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nature based redox materials can serve as electron acceptors and donors. • Complete nitrogen removal based on redox materials. • Emergence of a new pathway for anerobic ammonium oxidation. • Nature-based sustainable solutions for nitrogen management. Complete nitrogen removal depends on the requirement of oxygen as an electron acceptor and organics as electron donors. In the natural environment, these electron acceptors and donors regulate the nitrogen cycle in association with several nature-based processes, such as iron dependent (feammox), sulphur dependent (sulfammox), and nitrite dependent (annamox). These processes represent the latest discoveries in the nitrification part of the nitrogen cycle and provide the electron acceptors for anaerobic ammonium oxidation. Research findings on these processes suggest that a previously undescribed pathway is available for anaerobic ammonium oxidation, which can regulate the nitrogen cycle in natural environments. It has been shown that some redox active materials can serve simultaneously as electron acceptors and donors in the nitrogen cycle. This review provides comprehensive information of the known oxidative processes in the nitrogen cycle and highlights the emergence of a new pathway for anaerobic NH 4 + oxidation, which is dependent on insoluble redox active materials as electron donors and acceptors. This new pathway is not limited to anaerobic NH 4 + oxidation, but it also includes reductive pathways to nitrogen gas, and thus can lead to complete nitrogen removal from nitrogen environments. Recent developments and knowledge advancement in the nitrogen cycle open a new path for nature-based sustainable solutions for nitrogen management. This new knowledge can provide innovative and novel approaches for conventional NH 4 + removal processes. [ABSTRACT FROM AUTHOR]

• Biological nitrogen removal is a carbon source of wastewater treatment. • Nitrogen neutrality determines carbon neutrality of wastewater treatment. • Ammonium recovery is necessary for carbon–neutral wastewater treatment. • Nature inspired green approaches for ammonium recovery are highly desirable. • AnMBR coupled with microalgae can address the water-energy-resources nexus. With rapidly evolving global climate change, municipal wastewater treatment has been identified as a nonneglected carbon source contributing to about 1–2% of total carbon emissions worldwide. Given such a situation, the development of carbon–neutral municipal wastewater treatment process has become highly desirable and pressing. However, almost all wastewater ammonium is biologically converted to nitrogen gas in the present biological treatment processes of municipal wastewater, making ammonium recovery impossible. It is shown in this article that the current biological nitrogen removal (BNR) processes indeed are a significant carbon source, implying that nitrogen neutrality largely determines carbon neutrality of wastewater treatment. To tackle this challenge, ammonium recovery instead of BNR should be incorporated into future municipal wastewater treatment processes. Although several advanced bio/electrochemical approaches have recently been developed for ammonium recovery from municipal wastewater, their engineering and economic feasibility have not yet been determined. Instead, the nature-inspired green approach for recovery of wastewater ammonium should deserve more attention and effort. It is shown that an integrated anaerobic fixed-film membrane bioreactor-microalgae bacterial granular sludge process coupled with heat exchange can create a significant carbon sink, likely leading to carbon-negative municipal wastewater treatment. Consequently, it is reasonable to consider that the way forward is to explore a green-to-green engineering approach through harnessing the synergies among wastewater treatment, energy-heat-nutrients recovery, and carbon dioxide capture. [ABSTRACT FROM AUTHOR]

[Display omitted] • Multiple mediators function as electron shuttles to promote anammox process; • The EET capability of anammox bacteria can be facilitated by external mediators; • The concurrent presence of mediators triggered the activation of essential enzymes; • The application perspective should focus on the EET-enhanced anammox optimization. The anaerobic ammonium oxidation (anammox) process, transforming ammonia into nitrogen gas in oxygen-free environments using nitrite as an electron acceptor, is increasingly recognized for its potential in treating ammonium-rich wastewater. A major challenge for widespread application of this technology is the limited presence of nitrite in most wastewaters. The intrinsic electroactivity of anammox bacteria implies that the introduction of exogenous additives through the extracellular electron transfer (EET) process could effectively stimulate ammonia oxidation even in the absence of nitrite. This comprehensive review consolidates various approaches to enhance EET-dependent anammox, including the utilization of carbonaceous materials, metal ions, and humic substances. Molecular mechanisms involved in enhancing nitrogen removal performance based on extracellular electron transfer capacity are expounded. The co-occurrence of electron acceptors and exogenous electron shuttles is proposed to increase the activity of c-type cytochromes (c -Cyts) and N-acyl-homoserine lactones (AHLs) in extracellular polymeric substances (EPS), as well as enzymes such as hydrazine synthase (HZS) and hydrazine dehydrogenase (HDH), leading to stable a nitrogen removal performance. This review presents novel insights into the engineering of the EET-enhanced anammox process, providing a theoretical framework for its advancement and optimization. [ABSTRACT FROM AUTHOR]

[Display omitted] • Oxalate ions form a protective layer on zinc anode, inhibiting side reactions. • Oxalate ions alter solvation of zinc ions, replacing water molecules. • Oxalate ions promote Zn (0 0 2) crystal plane growth, optimizing deposition. • Ammonium ions shield zinc protrusions, suppressing tip effect. • Ammonium oxalate enhances cycle life in Zn-Zn cells and Zn-MnO 2 batteries. The natural reactivity of Zn metal in aqueous environments leads to surface deterioration and uncontrolled dendrite growth, posing challenges in the advancement of Zn-ion batteries. In this research, we introduce an environmentally friendly and cost-effective electrolyte additive, ammonium oxalate (AO), to significantly extend the cycle life of Zn-ion batteries with minimal usage. Oxalate ions within AO actively participate in the solvation of hydrated Zn ions and attach to the Zn anode surface prior to H 2 O molecules, creating a robust solid-electrolyte interface (SEI) layer. This SEI layer serves a dual purpose: it inhibits further reactions with H 2 O and restricts the two-dimensional movement of Zn ions, promoting the preferential growth of the (0 0 2) crystal plane. Consequently, Zn||Zn cells exhibit an impressive lifespan surpassing 1800 h (at 1 mA cm−2, 1 mAh cm−2), and Zn||Cu cells experience a tenfold increase in cycling life. Moreover, Zn||MnO 2 full cells, incorporating this low-cost and highly efficient inorganic additive, maintain an outstanding 80.84 % capacity retention after 1200 cycles at 1 A g−1. This breakthrough with AO offers a promising avenue for the practical implementation of Zn-ion batteries, emphasizing their cost-effectiveness and environmental sustainability. [ABSTRACT FROM AUTHOR]

[Display omitted] • Electro-oxidation of N-heterocycles produces N 2 , N H 3 / N H 4 + , N O 3 - , C O and C O 2. • N H 3 / N H 4 + and an apparent N 2 yield correlate linearly with carbon removal. • Both apparent N 2 and N O 3 - form directly from organic intermediates rather than N H 3 / N H 4 +. • Higher concentrations of parent compounds promote a higher apparent N 2 selectivity. • N O 3 - dominates when oxidation of carbon is mass transfer-limited or at basic pH. We report for the first time the carbon and nitrogen product distribution during the electrochemical oxidation (EO) of pyrazine and related N-heterocyclic compounds (NHCs) present in the hard-to-treat wastewater from a biofuel production process. The experimental study was carried out using a boron-doped diamond anode. Identified and quantified intermediate products included oxamic acid, formamide, oxalic acid, and formic acid. Analysis of the C and N yields as a function of the extent of carbon removal reveals the influence of the current- and mass transfer-control operating regimes on product distribution. Carbon monoxide, which was detected among the gaseous products, suggests a possible decarbonylation pathway in the current-controlled regime. An apparent nitrogen gas and ammonium yields correlated linearly with the carbon removal, while nitrate yields significantly increased in the mass transfer-controlled regime. Nitrate and apparent nitrogen gas appear to form directly from organic nitrogen intermediates, rather than from the ammonium that also forms in the process. The research gives new insights into the NHCs degradation pathways, product distribution, and final water composition as a function of operating regime in the EO of recalcitrant wastewater. [ABSTRACT FROM AUTHOR]

[Display omitted] • Flower-like hierarchical (NH 4) x WO 3 nanocrystal composed of tunnel nanobelts was constructed. • Tungsten bronze (NH 4) x WO 3 powder and film displayed remarkable reversible photochromism. • Proton-coupled electron insertion/de-insertion and ions exchange during color-switching were investigated. • Chromogenic (NH 4) y WO 3 :nH-based energy-saving windows realized excellent thermal radiation regulation. Understanding photochromism is crucial for developing new ways to modulate the optical responses of materials. Here, we prepared ammonium tungsten bronze (NH 4) x WO 3 , representing a significant advance in photochromism over the rarely chromogenic tungsten bronze. The high color difference, 12.89 and 30.49 for 10 s and 90 s exposure, respectively (AM 1.5G), was due to the large surface area created by the distinctive flower-like hierarchical structure, which exposed more photoactive sites, as well as to the highly efficient adsorption of the proton-coupled electron as a color center on the surface to trapped electrons. The elucidation of NH 4 + protonation under the light field and/or chemical interactions with neighboring protonated species was revealed by the ion exchange sites in hexagonal, trigonal, and square sites, suggesting an essential surface structure-breaking behaviors of hydrogen bonds between NH 4 + and tunneled WO 3 frameworks. In particular, the created energy-saving window, based on hydrogen ammonium tungsten bronze (NH 4) y WO 3 :nH/polyvinyl alcohol/polyvinylpyrrolidone coating, enabled a reduction of indoor air temperature by 6.3 °C in hot weather and reduced temperature difference between various indoor areas. The modification of the chemical environment of WO 3 and the identification of the photochromism mechanism hold promise for the development of energy-saving windows using chromogenic nanomaterials. [ABSTRACT FROM AUTHOR]

[Display omitted] • The deficient inorganic N, P, and C sources induced decline in S0AD efficiency. • Specific thresholds for inorganic N, P, and C to robust S0AD were established. • Substantial reduction in SOBs occurred under deficient inorganic nutrients. • External supplying mitigated nutrient constraints in a pilot-scale S0PB bioreactor. Elemental sulfur packed-bed (S0PB) bioreactors are increasingly employed to treat secondary effluents from wastewater treatment plants. Limited availability of inorganic nutrients, such as ammonium, phosphate, and inorganic carbon, significantly determines the growth of autotrophic microorganisms and the denitrification efficiency. This study investigated the constraining thresholds of inorganic nutrients on the elemental sulfur autotrophic denitrification process. In the absence of ammonium, phosphate, and bicarbonate, the denitrification rate decreased. Specifically, the ammonium assimilation process could be replaced by nitrate assimilation pathways, resulting in a 29.5 % decline in denitrification efficiency when the ammonium-N feed was reduced from 2.0 to 0 mg-N/L. However, the absence of phosphate-P and bicarbonate-C led to substantial drops in denitrification efficiency by 66.7 % and 77.5 %, respectively. This was primarily attributed to diminished biomass yield, as evidenced by reductions of 77.8–82.6 % in ATP and 35.7–44.3 % in protein content, along with a 12.4 %–14.7 % decrease in the relative abundances of dominant sulfur-oxidizing bacteria. Correlation analyses established specific thresholds for desired nitrate removal amounts: 0.131 for ammonium-N, 0.053 for phosphate-P, and 0.597 for bicarbonate-C. These thresholds provided valuable guidance for adjusting real-life wastewater through external supplementation when employing a pilot-scale S0PB bioreactor, leading to a significant enhancement of denitrification efficiency. This study emphasizes the significance of considering the concentrations of inorganic nutrients in wastewater when implementing S0PB bioreactors, which is a context that frequently neglects potential negative consequences. [ABSTRACT FROM AUTHOR]

[Display omitted] • V(V) reduction and denitrification, coupled with S0 oxidation, were observed. • 96.7 ± 2.2 % and 99.0 ± 1.1 % of V(V) reduction and NH 4 +-N oxidation were accomplished. • V(V) was reduced by MAGs containing genes (narG , napA) or MHCs (OmcB , MtrA). • NH 4 +-N was oxidized to NO 3 –-N/ NO 2 –-N, and then reduced to N 2 or assimilated. • NH 4 +-N oxidation was primarily facilitated by nitrifiers (e.g., Anaeromyxobacter sp.). The extensive use of ammonium (NH 4 +) as a precipitant in non-ferrous metallurgy, such as vanadium production, leads to the co-occurrence of toxic heavy metals and NH 4 +-N in the resultant wastewater. Finding an efficient and cost-effective method for simultaneously removing vanadate [V(V)] and NH 4 +-N in a single step has remained unexplored. This study presents a novel approach by establishing the synchronous bio-elimination of V(V) and NH 4 +-N in a sulfur (S0)-based autotrophic system. Remarkably, 96.7 ± 2.2 % of V(V) and 99.4 ± 0.8 % of NH 4 +-N were successfully removed within 24 hrs. V(V) was transformed into V(IV) precipitates, while S0 was oxidized into sulfate, achieving complete nitrogen removal. Fifty-six genomes were retrieved and constructed from metagenomic binning, unveiling symbiotic interactions involved in sulfur, nitrogen, and vanadium transformation. With the annotation of functional genes (e.g., nar , nir , nap , nor , nos , sox , sor , dsr) and multi-heme c-type cytochromes, it was identified that V(V) reduction and denitrification, coupled with S0 oxidation, were mediated by species such as Sulfuricurvum sp., Achromobacter sp., and Thiomonas sp.. Meanwhile, NH 4 + oxidation was accomplished by Anaeromyxobacter sp.. Furthermore, autotrophs harnessed inorganic carbon through the Calvin-Benson-Bassham and Wood-Ljungdahl pathways to synthesize organic intermediates, which were subsequently consumed by heterotrophic organisms (e.g., Pseudomonas sp.) to facilitate V(V) reduction and denitrification. The quantification of transcripts associated with genes responsible for V and N metabolism provided additional evidence of these metabolic pathways' existence. This study offers a sustainable and environmentally friendly strategy for mitigating the adverse environmental impacts of vanadium production wastewater. [ABSTRACT FROM AUTHOR]

[Display omitted] • The dual network strategy fabricated a 3D printing gel ink with shear-thinning rheology. • Printed hydrogel exhibits remarkable mechanical properties, transparency, biocompatibility, and adhesion. • This hydrogel accurately monitors body movement and electrocardiogram (ECG) signals. 3D printing of high-strength hydrogel remains a great challenge owing to trade-off between strength and printability. Herein, a zwitterionic strategy was proposed through electrostatic reversible interaction to improve the rheology of shear-thinning based on an agarose-based network. Therefore, this mechanism of dual network (DN) ultimately imparts the hydrogel with remarkable strength (with a tensile strength of 0.79 MPa and a compressive strength of 14.18 MPa) and ductility (with a toughness of 766%), while simultaneously possessing multiple functionalities, such as high transparency, excellent biocompatibility, and adhesion. Furthermore, the developed agarose/poly([2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium -co-N- hydroxyethylacrylamide) (A/D-H) DN hydrogel exhibited impressive strain sensitivity with a strain gauge factor GF of 4.33 even under large deformations. Various forms of flexible sensors based on this printed gel were successfully utilized in human motion sensing and remote heartbeat monitoring, thereby opening up new perspectives for the further expansion of injectable materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • NH 4 + inhibits the degradation of TBBPS in the heat/PDS system. • The reaction between NH 4 + and SO 4 •- generates the nitrating agent NO 2 •. • Coupling of NO 2 • and TBBPS radical intermediates generates nitrated products. • In situ formed free bromine can be scavenged by NH 4 + to form NH 2 Br. • NH 2 Br reacts with certain TBBPS intermediates yielding DBAN. Sulfate radical (SO 4 •-)-based advanced oxidation processes (SR-AOPs) show great potential in the elimination of organic pollutants in wastewater treatment and groundwater remediation. Tetrabromobisphenol S (TBBPS) as an emerging contaminant can be effectively degraded in SR-AOPs. However, the present study found that SO 4 •- also reacted with ammonium (NH 4 +), a ubiquitous inorganic nitrogen species in aquatic environments, thus markedly affected the rates and pathways of TBBPS degradation in SR-AOPs. TBBPS underwent β-scission and debromination upon SO 4 •- attack, leading to various transformation products. The released bromide (Br-) underwent further oxidation by SO 4 •- to form free bromine which reacted with certain TBBPS intermediates, generating disinfection byproducts (DBPs). When NH 4 + was present in such system, the abatement of TBBPS was apparently suppressed. Meanwhile, NH 4 + was oxidized by SO 4 •- to nitrogen dioxide radical (NO 2 •) which coupled with certain radical intermediates of TBBPS oxidation, yielding nitrophenolic products including 2,6-dibromo-4-nitrophenol (DBNP) and mono-nitro substituted TBBPS. When 10 μM TBBPS was treated by heat activated peroxydisulfate with 1 mM NH 4 +, the molar yield of DBNP reached 22% in 2 h. More importantly, NH 4 + scavenged the in situ formed free bromine to form monobromamine (NH 2 Br), decreasing regulated DBPs formation but leading to highly toxic dibromoacetonitrile (DBAN). This study broadens the understanding of interactions between the transformation of halogens and NH 4 + during SO 4 •- oxidation. It also reveals the potential environmental risks when SR-AOPs are employed for the organohalogen pollutants degradation in realistic environments where NH 4 + is present. [ABSTRACT FROM AUTHOR]

[Display omitted] • FA inhibition on microalgal growth and ammonium removal could be mitigated by COD. • Autotrophic consortium removed ammonium by algal assimilation and ammonia oxidation. • Microalgal and bacterial assimilation were main removal pathways in mixotrophic consortium. • Algal-bacterial consortia showed great N 2 O emission reduction compared to PN cultures. • FA enhanced reducing N 2 O emission by limiting oxygen and stimulating bacterial assimilation. The coupling of microalgae and partial nitritation (PN) cultures was a promising technology to treat ammonium-rich sidestream wastewater. However, limited information is available on nitrogen transformation pathways, N 2 O production mechanisms and their association with free ammonia (FA) in this symbiotic system. Enhanced ammonium removal (up to 100%) by the consortium was achieved mainly through algal assimilation (3.2–21.9%) and ammonia oxidation (33.2–72.7%) under autotrophic conditions, while bacterial assimilation (11.6–45.4%) had an important contribution under mixotrophic conditions as it was the least inhibited by FA. Higher FA concentration at the range of 6.53–45.70 mg/L would lead to an increase of N 2 O accumulation from 0.56 to 1.09 mg N/L, but a decrease of N 2 O emission factor from 0.6 to 0.3% in the mixotrophic consortium. At each FA level (6.53–58.76 mg/L), mixotrophic algal-bacterial consortium contributed to significant reductions of N 2 O accumulation by 60.5–83.8% and of N 2 O emission factors by 60.5–92.7% compared to the single PN cultures, with optimal mitigation scenario achieved at FA level of 45.70 mg/L. Herein, heterotrophic denitrification was deemed as the major sink for N 2 O production, while microalgal assimilation played an important role in limiting N 2 O emission factors as it restrained the nitrogen distribution to nitritation and denitritation. This might imply the potential of the consortium of microalgae and PN cultures in achieving higher ammonium removal while reducing greenhouse gas emission during sidestream wastewater treatment. [ABSTRACT FROM AUTHOR]

• TAN recovery via BES as a low-energy intensive alternative to conventional systems. • The TAN recovery rate highly depends on the current density produced. • Challenges for scale-up: nature/quantity of carbon source and NH 4 + concentration. • Describing fundamentals of BES TAN recovery: stripping, absorption or precipitation. Due to the anticipated rise in demand for ammonia, the search for viable methods for its recovery has intensified in recent years, as traditional ammonia production is a high energy intensive process. Bioelectrochemical systems (BESs) offer an alternative solution for ammonia recovery since they have shown lower energy demand (in terms of kJ g−1N recovered) at lab-scale than other methodologies. In BESs, the bioelectrochemically generated current drives the transport of NH 4 + from the wastewater to a concentration chamber through a cation exchange membrane before its subsequent recovery. This paper describes the fundamentals and opportunities for bioelectrochemical ammonia recovery (either by stripping, absorption, or precipitation) in different BES devices such as microbial fuel cells, microbial electrolysis cells, microbial desalination cells and bioelectroconcentration cells and compares the performance of all the reported experimental works so far. Moreover, the most critical challenges (low current density, nature and quantity of the carbon source, inlet ammonium concentration, use of membranes, energy yield and recovery efficiency) have been detailed and discussed in view of better understanding the current bottlenecks for its scale-up and, thus, for its prompt industrial adoption. [ABSTRACT FROM AUTHOR]

• Acidithiobacillus thiooxidans produce SO 4 2− in the ammonium-rich manure digestate. • NH 4 + biorecovery from the digestate by A. thiooxidans is feasible. • The biorecovered product contained 91% ammonium sulfate. Livestock production has an undesirable impact on the environment as livestock waste generates considerable volumes of manure digestate rich in ammonia nitrogen. The purpose of this study was to develop a treatment technology for biorecovery of ammonium (NH 4 +) from manure digestate to facilitate its use as fertilizer in the form of ammonium sulfate (AS). Our method offers an energy saving, environmentally friendly, and easily controlled way to address the environmental consequences of livestock. Here, the feasibility of NH 4 + biorecovery from the manure digestate by Acidithiobacillus thiooxidans (PTCC 1717) is shown. To conduct biorecovery, the bacterium was first adapted to high NH 4 + concentration by progressive acclimatization to improve its tolerance. Sulfate (SO 4 2−) accumulation of 57 mM at NH 4 +-rich manure digestate after 15 days of incubation exhibited good oxidizing ability of the acclimated A. thiooxidans. At last, the manure digestate rich in NH 4 + and biogenic SO 4 2− were dried at 60 °C and 6.02 g AS L−1 digestate was obtained. XRD and FTIR measurements confirmed the presence of AS in the biorecovered product. [ABSTRACT FROM AUTHOR]

[Display omitted] • Water was decomposed into H+ and OH– during ultrasonic activation. • H+ and OH– from water were combined with biochar, improving surface functional groups. • Different effects of ultrasound on adsorption process of biochar and Mg-biochar. • Ultrasound improved the Q m of NBC and NMBC by 1.30 and 1.31 times, respectively. Ammonium is one of the most important nutrients in agricultural wastewater, and its excessive existence will pose a threat to ecosystem and even human life. The cavitation effect generated by ultrasonic waves with huge energy can break the carbon bonds of biochar and thus increase the abundance of functional groups. In order to adsorb ammonium effectively in water, we used ultrasound to improve biochar or magnesium-loaded biochar performance in removing wastewater pollutant. Batch experiments with material characterization and adsorption models were conducted to assess adsorption characteristics. The nano-biochar (NBC) was obtained after the ultrasonic modification, with porosity, cation exchange capacity (CEC), zero point of charge (pH pzc), and functional groups (–OH, C–O, C–O–H, C–H) effectively being improved, indicating OH– and H+ were separated from water and bound to biochar to form functional groups during ultrasonic cavitation. The nano-Mg-biochar (NMBC) also increased the functional group of metal oxides. The ammonium adsorption of NBC and NMBC was dominated by intraparticle diffusion. The observed ammonium adsorption capacity of NBC and NMBC was best described by the Langmuir isotherm, implying the adsorption derived from the energetically homogeneous surface. Moreover, the maximum adsorption capacities for NH 4 + on NBC, and NMBC were 13.589, and 23.777 mg·g−1, respectively. Ultrasound improved the maximum ammonium adsorption capacity of raw biochar and Mg-biochar through electron attraction and ion exchange, respectively. Notably, ultrasonic modification causes a more uniform distribution of chemical crystals in the biochar and broken carbon bond to combine with more functional groups, which would be a significant way to reorganize functional groups directionally and optimize the adsorption performance of materials. [ABSTRACT FROM AUTHOR]

• Nutrient recovery from synthetic urine was limited for conventional Donnan dialysis. • A novel Donnan dialysis system was constructed with tubular ion-exchange membranes. • This reactor enabled simultaneous recovery of phosphate, ammonium, and potassium. • Struvite was successfully precipitated in the nutrient-enriched draw solution. • The tubular membrane reactor can be effectively scaled up for real applications. To address interconnected issues related to deteriorated water quality and unsustainable fertilizer production, Donnan dialysis was employed for nutrient recovery from model waste solutions and synthetic urine. Conventional Donnan dialysis reactors with flat-sheet, ion-exchange membranes and 500-mL solutions were deployed to determine the impact of the synthetic urine matrix on nutrient recovery relative to model wastes that only contained sodium phosphate (NaH 2 PO 4) or ammonium chloride (NH 4 Cl). Compared to the model wastes, the competing ions in the synthetic urine caused orthophosphate (P(V)) and ammonium (NH 4 +) removal to decrease from 90.4 % to 55.2 % and from 87.8 % to 84.8 %, respectively. To improve reactor design for future scale up, an innovative Donnan dialysis system was established by placing tubular anion- and cation-exchange membranes into a 30-L waste solution and continuously recirculating 5 L of an NaCl-based draw solution through the inside of the membranes. P(V), NH 4 +, and other nutrients were simultaneously recovered, and the concentrations in the draw solution exceeded those in the initial synthetic urine in accordance with Donnan equilibrium for unequal solution volumes. Over 75 % P(V) and 74 % NH 4 + were removed from the synthetic urine. MgCl 2 and NaOH were added to the nutrient-enriched draw solution to precipitate solids and reset the electrochemical potential gradient, enabling enhanced nutrient recovery. Chemical equilibrium modeling and solids characterization confirmed that the recovered precipitates were ∼73–90 % struvite. The proof-of-concept tubular reactor represents a promising strategy for scaling up Donnan dialysis systems for selective nutrient recovery from urine and other wastes. [ABSTRACT FROM AUTHOR]

Portable smartphone platform offers a new strategy for on-site and visual quantitative detection of ammonium nitrogen in soil and wastewater samples. [Display omitted] • OPA/K 2 SO 3 /R-QDs and OPA/K 2 SO 3 based sensor have been respectively used for determination of low and high concentration range of NH 4 + via two response modes. • The color responses toward the NH 4 + concentrations have been systematically studied. • The proposed strategy can realize visual quantitative detection of NH 4 + in real samples. • Portable smartphone platform brings great convenience for on-site detection of NH 4 +. Ammonium (NH 4 +) is crucial for plant growth as well as various industrial processes, the accurate and field measurement of the NH 4 + level is of great significance for agricultural precision fertilization and water quality monitoring, but excessive amounts of ammonium can lead to eutrophication of aqueous environments. Herein, the ability of the proposed probe solution and test paper to colorimetric change towards high-concentration NH 4 + and ratiometric fluorescence response to low-concentration NH 4 + has been developed for visual detection of ammonium in real samples. Specifically, high concentration of NH 4 + (0.5–7 mM) could interact with the o-phthalaldehyde (OPA) in presence of K 2 SO 3 , resulting in the colorimetric transition from colorless to wine-red with increasing the NH 4 + concentration. Subsequently, the addition of the red-emitting CdTe QDs (R-QDs) constructed the OPA/K 2 SO 3 /R-QDs ratiometric fluorescent probes for low-concentration NH 4 + (less than 1 mM) sensing with a limit of detection (LOD) down to 18 nM, accompanied by a distinct fluorescence color shift from red to blue under UV light. Furthermore, the visualization detection integrated with smartphone was converted to data information (RGB value) through a Color Recognizer APP and successfully used for visual quantitative identification of NH 4 +. Actually, the proposed probe solution and test paper have been applied to the determination of NH 4 + in soil extracts and wastewater samples. Compared with the standard methods, this established strategy can supply stable and reliable detection results, and allow fast sensing at room temperature, exhibiting great application potential for visual on-site detection of NH 4 + at different concentration ranges in environmental samples. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel composite (FeO x -MgO) was synthetized and used to selectively oxidize NH 4 +. • The base sites on FeO x -MgO composite are crucial for the conversion of NH 4 + to NH 3. • NH 3 can be easily oxidized to ammonia hydride by PS mainly activated by hv. • Fe(IV) formed in FeO x -MgO/PS/ hv system enhanced the selectivity of NH 4 + oxidation. The selective oxidation of ammonium nitrogen (NH 4 +-N) to dinitrogen (N 2) by advanced oxidation processes (AOPs) is of paramount significance, but it is still a great challenge. In this study, a novel composite (FeO x -MgO) was synthesized to activate persulfate (PS) for selective oxidation of ammonium (NH 4 +) to N 2 under simulated solar-light irradiation (hv). The results demonstrated that the conversion of NH 4 + to ammonia (NH 3) on the basic sites of FeO x -MgO was a key step for the selective oxidation of NH 4 +. Fe(IV) species formed in FeO x -MgO/PS/ hv system could enhance both the efficiency and N 2 selectivity of the NH 4 +-N oxidation through the oxidation of ammonia hydride to N 2. The 100 % NH 4 +-N removal and over 95.5 % N 2 selectivity could be achieved after 30 min when initial pH was in range of 2–10, and the initial NH 4 +-N concentration was 30 mg N/L. This study could provide a promising technology for the selective oxidation of NH 4 +-N to N 2 in water and wastewater. [ABSTRACT FROM AUTHOR]

[Display omitted] • Combining Bio-Electrochemical and Electrochemical System for NH 3 recovery. • Utilizing one shared cathode for the Bio-Electrochemical and Electrochemical System. • The combined system showed high NH 3 removal 99.8 % at a low energy input 9.2 MJ/kg N. • NH 3 effluent concentration complied with European Urban Water Framework Directive. • Bio-anode instabilities can be compensate by the electrochemical system. Bio-electrochemical systems (BESs) can recover ammonium at low specific energy inputs and can produce hydrogen gas. A reason hampering development of large-scale applications for ammonium recovery is the general instability of the bio-generated current and the thereby variable TAN (ammonia and ammonium) effluent concentrations. Electrochemical systems for ammonium recovery, such as the hydrogen recycling electrochemical system (HRES), can fine-tune the applied current, but require higher specific energy inputs than BES, and may require an additional external hydrogen supply in case of HRES. This research presents for the first time an integrated BES and HRES system for ammonium recovery to combine the advantages of both types of systems to achieve high TAN removal efficiency at low specific energy input. The HRES was able to partially compensate for BES instability, which resulted in an overall high TAN removal efficiency (89–95 %) at an increased energy demand of 5.2–10.2 MJ/kg N. When the BES was performing stably and efficiently, the HRES removed almost all of remaining TAN at up to 99.8 % overall TAN removal efficiency, requiring 9.2 MJ/kg N. The combined system can remove TAN down to much lower effluent concentrations at little to no additional energy input. These results indicate that combining BES and HRES in one system can result in TAN recovery that is more efficient than in each system separately, which could facilitate new application possibilities for (bio-)electrochemical ammonium recovery. [ABSTRACT FROM AUTHOR]

[Display omitted] • PN achieved within 28 days and maintained about 80 days with paracetamol dose. • Achieving PN by paracetamol was independent of floc, granular sludge or biofilm. • After combining with low DO, PN could recover within 10 days and last for 150 days. • Nitrospira (Oligotype 1) and nxrB inhibition were the reasons of PN by paracetamol. • The inhibition of Nitrotoga by paracetamol and low DO broke the bottleneck of PN. Achieving stable partial nitrification (PN) are the basic guarantee of anaerobic ammonia oxidation (anammox) process. However, there is no recognized feasible method for rapidly achieving stable PN in municipal wastewater, and further research is necessary. In this study, paracetamol was proved as an effective nitrite oxidation inhibitor through long-term experiment lasting 392 days in three systems (floc sludge, granular sludge, biofilm). PN of low-strength ammonium wastewater was rapidly achieved within 28 days and maintained for about 80 days after paracetamol dose, whereas PN recovered again within 10 days and sustained over 150 days under paracetamol dose combined with low dissolved oxygen strategy. The inhibition effect of paracetamol on NOB was almost not affected by biomass growth modes. QPCR and high-throughput sequencing showed that Nitrospira (Oligotype 1) was inhibited by paracetamol, and PICURSt2 analysis indicated its key enzyme NXR was significantly downregulated after paracetamol treatment, which were the key reasons of PN start-up in three systems. The emergence and adaptation of Nitrotoga was the main reason for the instability of PN. This study proved that paracetamol could be used as a novel nitrite oxidation inhibitor, and provided a possibility to achieve the mainstream PN and anammox for treating wastewater with low-strength ammonium. [ABSTRACT FROM AUTHOR]

[Display omitted] • Upgrading nitrogen removal performances in wastewater treatment plants by BES. • Enhancing the polishing action of secondary treatments to avoid tertiary treatments. • Nitrate and ammonium removal without nitrous oxide accumulation. • Disinfection of wastewater via electrochemical anodic oxidation. Economic options to retrofit wastewater treatment plants (WWTPs) without tertiary treatments need to be explored. In this regard, bioelectrochemical systems (BES) can be hybridized with existing technologies, upgrading the removal performance of original techniques while avoiding replacement costs. Yet, few demonstrations of merged systems have been given. For the first time, in this work it was built a lab-scale model of a BES merged with a secondary settler, namely e-settler, to enhance the polishing performance of already existing WWTPs. In particular, to concomitantly increase nitrogen removal and perform wastewater (WW) disinfection, avoiding further tertiary treatments. In the e-settlers, nitrogen removal was increased through bioelectrochemical stimulation. Concomitant ammonium and nitrate removal without nitrite accumulation and a negligible amount of nitrous oxide emissions were observed. Ti-MMO as anode material showed a high disinfectant action. In conclusion, it was demonstrated how a simple bioelectrochemical set-up can upgrade existing WWTPs. The following step requires the study at a larger scale, identifying optimal operational and structural parameters for the in-situ application. The main limitations of the e-settlers were discussed, linking them to possible solutions that need to be deepened in a lab-scale model of conventional secondary treatments (activated sludge followed by secondary settler). [ABSTRACT FROM AUTHOR]

This is a sketch showing the main contents of this work. In this work, a novel fire-resistant cotton fabric by combining SWCNHs and ammonium polyphosphate was proposed. The effects of different concentrations of SWCNHs on the flame retardancy of fabric were investigated, and the mechanism of flame retardancy for SWCNHs was also discussed in detail. [Display omitted] • Single-walled carbon nanohorns (SWCNHs) was first reported for flame retardancy. • High flame retardant performance was achieved by SWCNHs with low mass loading. • The incorporation of SWCNHs can greatly reduce the damage length of cotton fabrics. • The synergistic flame retardant mechanism of SWCNHs was described in detail. The development of environmentally friendly flame retardants that can achieve high efficiency for textiles at low addition levels is of great significance to human life and environmental protection. Halogen flame retardants have long dominated in flame retardant applications. However, there are increasing calls to ban its use because of the threat they pose to human health and the environment. Herein, this work investigated the potential of a novel carbonaceous nanomaterials-single-walled carbon nanohorns (SWCNHs) coating material for flame retardancy of cotton fabrics. The unique combination of SWCNHs and ammonium polyphosphate (APP) in a single halogen-free nanocoating has a synergistic effect, which endows cotton fabric with prominent fire resistance. When the addition amount of SWCNHs was 0.15 %, the limit oxygen index (LOI) could reach 27.5 ± 0.83 %, and the damage length decreased from 30 ± 0.01 % cm to 6.5 ± 0.06 % cm. SEM results showed that Cotton-APP/SWCNHs (0.15) still displayed well-preserved woven structure after the vertical flammability test. Additionally, the pHRR and THR of Cotton-APP/SWCNHs (0.15) were markedly decreased by 92.22 % and 58.44 %, respectively in the cone calorimeter test. Meanwhile, the flame retardant mechanism analysis confirmed that the incorporation of SWCNHs into the APP coatings promoted the formation of dense and stable graphitized carbon layer on the surface of the cotton fabric, and effectively prevented the generation of combustible volatiles, thus enhancing the flame retardant performance of cotton fabrics. This work provides a new insight into developing carbon nanomaterials for flame retardant polymeric materials and extending the application of SWCNHs. [ABSTRACT FROM AUTHOR]

[Display omitted] • Polarized hydroxyapatite (p-HAp) catalyzes the yield of NH 4 + starting from N 2. • The synthesis is performed at low pressure and temperatures below 120 °C. • The yield of ammonia is 154.6 ± 25.8 μmol/g of catalyst. • p-HAp catalyst does not need external electrical field for nitrogen fixation. • p-HAp can be also used to recycle CO 2 from polluted air. Polarized hydroxyapatite (p-HAp), a calcium phosphate catalyst obtained at high temperature under intense electric field, has been used for the synthesis of ammonium starting from N 2 and liquid water at low pressure (<6 bar) and temperatures below 120 °C. The success of the nitrogen fixation process has been demonstrated by isotope labelling experiments using 15N 2. Considering the optimal reaction conditions for the production of ammonium, the yield is as high as 154.6 ± 25.8 μmol/g of catalyst. The proposed synthesis exhibits three important advantages for its utilization in green chemistry environmental processes related to the recycling of polluted air. These are: i) the catalysts converts CO 2 into valuable chemical products in addition of transforming N 2 in ammonium; ii) the final energy balance is very favorable since no external electrical field is necessary to promote nitrogen and carbon fixation reactions; and iii) products are easily transferred to water favoring their extraction and avoiding the saturation of the catalyst. [ABSTRACT FROM AUTHOR]

[Display omitted] • The limited step for N removal depended on the presence of plants. • The plants and low water level improved NH 4 + - N rather than TN removal. • N genes and nitrifying populations were affected in later period by treatments. • Cooccurrence network and associated heatmap evidenced interaction of N removal. • The differences in six core pathways of N metabolism depended on CW type. With occurrence of emerging contaminants in wastewater, nitrogen metabolism in constructed wetlands (CWs) should be re-evaluated at different environmental variables to withstand adversely exogenous contaminants. This study investigated functional gene, key enzyme, and microbe regulating nitrogen metabolism in three different configuration design CWs (planted W1 and W3 with full and low water level, unplanted W2 with full water level) when exposed to graphene oxide, one of most popular carbon-based nanomaterials. It was found that nitrogen removal was achieved by classical nitrification and denitrification, which was limited by nitrification in W2 and denitrification in planted CWs, presenting optimal balance between nitrification and denitrification in W1. Compared to W2, ammonium removals increased by 48% and 107% in W1 and W3, conversely total nitrogen removals decreased by 6% and 14% due to nitrate accumulation. Ammonia monooxygenase was the most sensitive to variables among four key enzymes. Bacteria were more abundant than archaea in CWs, both of functional genes and nitrifying populations were obviously affected by plant and water level in later period. The dominant denitrification populations were class Gammaproteobacteria followed by Alphaproteobacteria with the highest abundance observed in W2. Their species richness at genus level was higher on day 30 in W2 than planted CWs, but similar on day 120 in three CWs. The cooccurrence network and associated heatmap evidenced complex interaction among key enzymes, functional genes, and functional genera for nitrogen removal. KEGG annotations revealed specific differences in six core pathways of nitrogen metabolism in three CWs. [ABSTRACT FROM AUTHOR]

[Display omitted] • Simultaneous V(V) and NH 4 +-N removals are achieved in a MBfR. • V(V) is reduced to insoluble V(IV) confirmed by SEM and XRD characterization. • Nitrification/denitrification bioprocesses achieve NH 4 +-N removal. • Pseudomonas cooperates with others for V(V) and NH 4 +-N removals. • The gene abundances increase with improved enzyme activities for nitrogen cycling. Ammonium (NH 4 +) is commonly used as either a precipitant or extractant in metallurgy of non-ferrous metal and rare earth ore (e.g., vanadium). This results in the coexistence of toxic metal and NH 4 +-N in the effluent. Despite its toxicity, there remains little in the way of biological treatments to synchronously eliminate vanadate [V(V)] and NH 4 +-N in vanadium smelting wastewater. In this study, simultaneous V(V) and NH 4 +-N removal was achieved using a membrane biofilm reactor (MBfR). The removal efficiencies for V(V) and NH 4 +-N reached 96.8 ± 0.8% and 75.4 ± 1.2%, respectively, with initial concentrations for both beginning at 10 mg/L along with a hydraulic retention time at 36 h. V(V) was mainly reduced to V(IV) precipitates. Complete nitrogen removal was achieved with negligible NO 3 –-N/NO 2 –-N accumulation. Pseudomonas was identified as the main contributor to V(V) reduction, nitrification, and denitrification. The identified V(V) reducers and nitrifying/denitrifying bacteria were positively related to the V(V) and NH 4 +-N removal capacity of MBfR. The increased gene abundance and improved enzymic activity for nitrogen cycling collectively evidenced that V(V) reduction was catalyzed by denitrification enzymes and NH 4 +-N was removed through nitrification/denitrification. Collectively, the results from this study offer a novel strategy for the treatment of vanadium-bearing smelting wastewater by eliminating V(V) and NH 4 +-N in a one-step bioprocess. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hyperthermostable quaternary ammonium monomers are designed and synthesized. • In-reactor engineering of antibacterial polyesters in a large scale is provided. • The functional polyester in this work is absent from any catalyst. • The resultant polyester exhibits strong and persistent antibacterial activity. It will be a significant advance if polyesters exhibit intrinsically antibacterial property considering their wide usage in the biomedical field, non-woven fabrics and food storage. Given the poor durability and low efficiency of physically blending or post-modification with antibacterial agents, melt polycondensation using polymerizable antibacterial agents as comonomer is potentially the most versatile and efficient approach for large scale production of polyesters with intrinsic antibacterial property. However, organic antibacterial agent fails to be used as comonomer for melt polycondensation due to its poor thermal property. Herein, a facile and green strategy is proposed for the synthesis of quaternary ammonium monomers via the reaction between sodium 5-sulfoisophthalic acid and various quaternary ammoniums in water, producing a series of antibacterial monomers with the highest thermal degradation temperature up to 361 °C. Finally, antibacterial poly(ethylene succinate) (PES) was synthesized via catalyst-free melt polycondensation from ethylene glycol and succinic acid using 1-hexadecyl-3-methylimidazolium 5-sulfoisophthalic acid as comonomer. The resultant functionalized PESs exhibit comparable physiochemical properties to pure PES, with additional superior and persistent antibacterial activity. This work provides a feasible strategy for the large scale production of antibacterial polyesters through in-reactor engineering. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Ru@β-HATB/CC hybrid is firstly synthesized as an efficient HER electrocatalyst. • β-HATB support can optimize the hydrogen adsorption/desorption behavior on Ru surface. • The Ru@β-HATB/CC exhibits a Pt-like activity with the overpotential of 25 mV. Reasonable structure design and fine electronic modulation are the keys to achieving the platinum-like hydrogen evolution reaction (HER) performance on Ru-based catalyst, but also challenges. Here, the integration of uniformly dispersed ultra-fine Ru nanoparticles with β-hexagonal ammonium tungsten bronze (β-HATB) nanowires is reported as an efficient acidic electrocatalyst. Due to the strong metal-support interaction, the surface charge state of Ru is effectively regulated, forming a mixed valence state composed of zero valence and offset state. The prepared Ru@β-HATB/CC exhibits a Pt-like catalytic activity with a small overpotential of 25 mV and a very low Tafel slope of 27.6 mV dec−1. In-situ Raman spectroscopy and electrochemical analysis reveal that β-HATB does not directly participate in HER reaction and hydrogen spillover effect (H ads from β-HATB to Ru NPs) is not the main reason for the hydrogen evolution activity, but β-HATB can optimize the kinetics of hydrogen adsorption/desorption behavior on Ru surface and provide a stable and fast charge transfer channel, thus improving HER activity. [ABSTRACT FROM AUTHOR]

[Display omitted] • Continuous aeration in membrane-aerated biofilms resulted in full nitrification. • Intermittent aeration suppressed nitrite oxidation and supported anammox process. • Biofilm pH presented periodic upshifts with aeration switches. • Free ammonia speciation likely caused the inhibition of nitrite-oxidizing bacteria. • Heterotrophs established nitrous oxide-reduction zones under intermittent aeration. Membrane-aerated biofilm reactors (MABR) are being applied for autotrophic nitrogen removal, yet control of nitrogen turnover remains challenging in MABR counter-diffusion biofilms. In this study, we regulated microbial activities in two lab-scale MABRs by providing continuous versus intermittent aeration. Nitrogen consumption by different functional microbial groups was estimated from bulk measurements via a mass balance approach. Nitrite-oxidizing bacteria (NOB) proliferated under continuous aeration while they were significantly suppressed under intermittent aeration, and NOB suppression activated anaerobic ammonium oxidation. Nitritation performance in the MABR was studied through long-term bulk measurements and in situ biofilm microprofiles of dissolved oxygen (DO) and pH. During intermittent aeration pH effects rather than DO effects determined nitritation success, especially ammonia speciation, which serves as substrate and inhibitor in nitrification processes. Biofilm transition phases were monitored upon aeration switches. Canonical correspondence analysis suggested that the relative transition after anoxia and aeration intermittency were less decisive for biofilm performance than the relative aeration duration. Heterotrophic bacteria displayed minor denitrification rates with aeration control, but contributed to mitigation of nitrous oxide (N 2 O) emissions. N 2 O production hotspots were identified at the top of the anoxic biofilm zone under continuous aeration. Instead, under intermittent aeration an anoxic N 2 O reduction zone was established. Our observations support intermittent aeration control of MABRs as a simple strategy for energy-efficient nitrogen removal with low N 2 O emission.. [ABSTRACT FROM AUTHOR]

• Ammonium polyphosphate as a green phosphorus source is reported for the first time; • The supramolecular precursor is self-assembly by coordination and electrostatic interactions; • MoP/MoNiP@NC exhibits remarkable and stable HER performance; • Density functional theory (DFT) calculation assigns negative P sites as best active sites. Transition metal phosphides (TMPs) have increasingly become the research focus of hydrogen evolution catalysts. In this paper, bimetallic phosphide electrocatalyst (MoP/MoNiP@NC) is prepared by predesigned supramolecular gels as precursors via a simple carbonization and phosphorating process, which experience a self-assembly process of ammonium polyphosphate (APP), phosphomolybdic acid hydrate (PMo 12), polyaniline (PANI) and Ni2+ ions via electrostatic and coordination interaction during heating in aqueous solutions. Ammonium polyphosphate as a new phosphorus source with non-toxicity and non-corrosive gas is reported for the first time and exhibits strong coordination ability with metal ions and polyoxometalate. MoP/MoNiP@NC displays satisfactory hydrogen evolution activity with low overpotentials of 94 and 137 mV at 10 mA cm−2 as well as excellent durability for 24 h in 1.0 M KOH and 0.5 M H 2 SO 4 , respectively. It is worth noted that the hydrogen evolution performance of the electrocatalyst is superior to the commercial Pt/C at a current density greater than 80 mA cm−2 under alkaline solution. The remarkable HER activity can be attributed to the synergistic effect of MoNiP and MoP nanoparticles, N-doped porous carbon layers protecting the nanoparticles from corrosion, exposing large amount of active sites and enhancing the mass transfer process. Density functional theory (DFT) calculations illustrate that the best active sites come from the negative P sites of MoNiP nanoparticles. This work provides an environment friendly and reproducible strategy for using APP as a green phosphorus source to synthesize transition metal phosphides as efficient electrocatalysts for energy conversion. [ABSTRACT FROM AUTHOR]

[Display omitted] • An electricity-driven microbial electrochemical recovery conversion cell was developed. • Effects of applied voltage and initial ammonium concentration were investigated. • CO 2 and wasted nitrogen from real waste streams were upcycled as microbial protein in the system. • The system showed a high energy efficiency with additional environmental benefits. Currently, hydrogen-oxidizing bacteria (HOB) based power-to-protein is a promising approach to produce alternative microbial protein (MP), however, the nitrogen source used was either derived from commercial products or was firstly recovered from waste streams and then diluted for HOB growth. In the present study, simultaneous ammonium recovery from wastewater and in-situ utilization for the green MP (derived from Cupriavidus necator 335) production was successfully demonstrated using a microbial electrochemical recovery conversion cell (MERC). 0.41 ∼ 0.82 g/L of dried biomass (protein content 49 ∼ 63%) was yielded in 36 h with a power supply of 3, 4, and 5 V. C. necator 335 could grow in the MERC system receiving wastewater with a broad range of ammonium (0.05 ∼ 8 g N/L) and the highest biomass production of 0.9 g/L (protein content 54%) was achieved at 2 g N/L. 2.69 g/L of dried biomass containing 57% protein was obtained in 120 h with an initial supply of 1 L CO 2 and 2 g N-NH 4 +. Applied voltages and ammonium concentrations showed a minor impact on the amino acid profile. Furthermore, the MERC system was tested with real waste streams (e. g., municipal wastewater, and digestate) and 0.45 ∼ 1.22 g biomass/L (protein content 52 ∼ 62%) were harvested. The characteristics of the wastewater streams (e. g., ammonium concentration and conductivity) could significantly affect the system performances. The harvested MP from real wastewater showed a high quality of amino acid profile and implied a potential in substituting traditional plant/animal-based protein. [ABSTRACT FROM AUTHOR]

[Display omitted] • CA-MB is synthetized to simultaneously remove PO 4 3− and NH 4 + from water. • Surface precipitation mainly contributes to the adsorption of PO 4 3−. • Electrostatic attraction and ion exchange dominate the adsorption of NH 4 +. • The retention capacity of CA-MB for PO 4 3− is better than NH 4 +. The eutrophication of aquatic environments has become one of the major environmental problems. To reduce nitrogen and phosphorus in water, industrial waste (distillers grains), agricultural waste (rice straw), and an invasive plant (Eupatorium adenophorum) were used to prepare ball-milled biochar (BMB), and further synthesize calcium alginate-biochar composite (CA-MB) for simultaneous adsorption of phosphate and ammonium. The scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), Zeta potential, X-ray diffractometer (XRD), and BET specific surface area (SSA) analyzer were used to characterize the physicochemical properties of CA-MB. The effects of different conditions (pyrolysis temperature, dosage, solution pH, and coexisting ions) on the adsorption performance were studied. Combined with adsorption kinetics and isotherms, the co-adsorption performance and governing mechanisms of phosphate and ammonium onto CA-MB were explored. The results showed that the CA-MB prepared from distillers grains, rice straw and Eupatorium adenophorum had better adsorption performances on phosphate and ammonium at the pyrolysis temperatures of 600 °C (CA-MWB600), 300 °C (CA-MRB300), and 600 °C (CA-MEB600), respectively. The maximum adsorption capacities of CA-MWB600, CA-MRB300, and CA-MEB600 for phosphate and ammonium estimated with Langmuir isotherm model were 24.1, 31.8, 24.0 mg g−1 and 12.27, 10.15, 9.90 mg g−1, respectively. The main adsorption mechanisms for phosphate were electrostatic attraction, surface precipitation, and ligand exchange, while for ammonium were ion exchange and electrostatic attraction. The retention capacity of CA-MB for phosphate was better than ammonium. This study indicates that CA-MB can be used as an effective adsorbent for simultaneous recovery of phosphate and ammonium from water. [ABSTRACT FROM AUTHOR]

[Display omitted] • In-situ synthesis/purification integration (ISSPI) strategy was adopted for NH 4 + and PO 4 3- removal. • The strategy was achieved based on constructing Mg-doped tricalcium aluminate (Mg-C 3 A). • Mg-C 3 A exhibited excellent capacities for NH 4 + (43.0 mg·g−1) and PO 4 3- (20.2 mg·g−1). • The hydration properties of Mg-C 3 A played vital roles in the ions removal/recovery. • ISSPI strategy using Mg-C 3 A was compelling for authentic wastewater treatment. Simultaneous capture of ammonium (NH 4 +-N) and phosphate (PO 4 3−-P) in digested piggery wastewater is of great urgency yet remains a challenge. Recently, the in-situ synthesis/purification integration (ISSPI) strategy, with the essence of converting contaminations to high value-added products, has aroused great enthusiasm in the environmental remediation realm. In the present work, we employed ISSPI method for simultaneous elimination and recovery of NH 4 + and PO 4 3- from digested piggery wastewater based on the construction of a novel material system, i.e. , Mg-doped tricalcium aluminate (Mg-C 3 A), which coupled the features of cement-based material tricalcium aluminate (Ca 3 Al 2 O 6 , C 3 A) and Mg dopants. The released metal cations (Ca2+, Mg2+, and Al(OH) 4 −) of Mg-C 3 A were expected to act as precipitation agents to capture NH 4 + and PO 4 3− via the formation of Ca(NH 4) 2 (HPO 4) 2, MgHPO 4 ·3H 2 O or AlPO 4 ; OH− established an alkaline environment for the enhancement of NH 4 + removal via neutralization; Mg2+ played a major role in the recovery of NH 4 + and PO 4 3−, with the formation of valuable struvite as fertilizer. Benefited by these functions, Mg-C 3 A exhibited superior removal capacity for NH 4 + (43.0 mg·g−1) and PO 4 3− (20.2 mg·g−1). More importantly, the ISSPI method using Mg-C 3 A was prospective to be applied for authentic effluent treatment as demonstrated by response surface methodology (RSM), with the concentration of both ions down to the discharge standard of livestock and poultry breeding, China (80 mg·L−1 for NH 4 +; 8 mg·L−1 for PO 4 3−). This research provided an alternative and promising approach for the simultaneous removal and recovery of NH 4 + and PO 4 3− from digested piggery effluent, shedding light on environmental remediation. [ABSTRACT FROM AUTHOR]