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The depletion of phosphorus resources and the problem of environmental pollution are driving the advancement of traditional methods for wastewater treatment. Researchers have taken an interest in microalgae-based processes, which offer a sustainable approach by effectively converting phosphorus into biomass. To improve the environment and make better use of waste phosphorus resources, the efficiency of phosphorus removal by microalgae must be increased. Therefore, studying the mechanisms of phosphorus uptake by microalgae cells is valuable. This review outlines the typical microalgae systems used for phosphorus removal from wastewater. It summarizes the procedures of phosphorus surface adsorption, membrane transport, and intercellular utilization by microalgae. Additionally, this work analyzed the phenomena of excess phosphorus uptake and emerging organic phosphorus uptake by microalgae. Furthermore, the article examines the primary external factors that affect phosphorous removal. Lastly, this review proposes utilizing microalgal biomass phosphorus in fertilizer and transition metal phosphide catalysts. This review provides innovative approaches for removing phosphorus from wastewater and applying microalgal biomass phosphorus. Article highlights: The treatment of P-contained wastewater by microalgae systems is summarized. Possible phosphorus metabolism pathways in microalgae are described. The uptake and utilization of organophosphorus by microalgae was highlighted. The application of microalgal biomass phosphorus in catalysts is discussed. [ABSTRACT FROM AUTHOR]

Iron-based materials are considered as excellent environmental catalysts due to the characteristics of abundant reserves, low biological toxicities, and rich chemical states for redox reactions. The sea urchin-like microscopic morphology of biosynthesized schwertmannite (Sch) with abundant surface active sites is beneficial to the environmental catalytic process. In this study, flake-type graphitic carbon nitride (g-C 3 N 4) was introduced into the mineralization process of Acidithiobacillus ferrooxidans (A. ferrooxidans) as the additive to regulate the biomineralization process and directly control the morphology and structure of iron-based minerals. Schwertmannite@g-C 3 N 4 composites (Sch-CN) with a desired structure of sea urchin-like well-dispersed biosynthesized Sch loaded on flaky g-C 3 N 4 were successfully prepared by A. ferrooxidans -induced biomineralization process. A Light/Peroxymonosulfate/Sch-CN catalytic system was constructed to degrade the model organic pollutant bisphenol AF (BPAF). The system combined two advanced oxidation systems of photocatalysis and peroxymonosulfate (PMS) activation, showing excellent catalytic degradation ability and wide pH adaptability. In addition, the system was also applicable to the catalytic degradation of other bisphenol pollutants. The mechanism was deduced by the results of quenching experiments and electron paramagnetic resonance (EPR) measurements. Several degradation intermediate products were identified and the probable degradation pathways of BPAF were proposed. The toxicity activities of BPAF solution towards Raphidocelis subcapitata were largely reduced after treatment by the photochemical process. Overall, the Light/PMS/Sch-CN system has great potential in treating bisphenol wastewater. [Display omitted] • Addition of g-C 3 N 4 successfully regulated the structure of biosynthesized Schwertmannite. • Light/PMS/Sch-CN 2 catalytic system led to efficient degradation of BPAF. • Synergistic effect of Sch-CN 2 with light for PMS activation was explored. • T.E.S.T program and growth inhibition test revealed the detoxification of BPAF. [ABSTRACT FROM AUTHOR]

The development of nuclear energy has brought a great challenge of the efficient treatment of spent radioactive ion exchange resin, and oxidative pyrolysis is a potential method of solving this issue. This study aims to investigate the oxidative degradation and conversion mechanism of tar and off-gas, byproducts produced in the pyrolysis process, in the presence of a catalyst, manganese dioxide. The results show that it presents three processes including liquefaction, gasification and direct gasification in pyrolysis, in which manganese dioxide could reduce the dominant temperature of gasification by 200 ℃. Tar and off-gas undergo secondary pyrolysis, and the yield of tar decreased by approximately 50%. Simultaneously, manganese dioxide could promote the conversion of tar into off-gas, making both of them simplified, for which long-chain hydrocarbons are transformed into short-chain hydrocarbons, CO 2 , H 2 O, H 2 , etc. The catalytic oxidation effect of manganese dioxide is attributed to the adsorption and catalysis of oxygen vacancy, which significantly simplifies the composition of tar and off-gas. [Display omitted] • The complex tar has been converted into simple off-gas. • The tar and off-gas produced by pyrolysis get great simplification and safe disposal. • The possible catalytic oxidation processes of tar and off-gas have been proposed. • The conversion mechanism of products gets in-depth interpretation. [ABSTRACT FROM AUTHOR]

Metal-free carbon catalysts perform well in peroxymonosulfate-based advanced oxidation process for the treatment of organic pollutant-containing wastewater. Herein, a natural biomolecule of adenosine triphosphate (ATP), containing abundant N and P elements, served as sole precursor to prepare N,P-co-doped carbon through one-step anoxic pyrolysis, which was applied as peroxymonosulfate activator to treat bisphenol-contaminated water. Owing to the endogenous N and P elements in ATP, in-situ doping was achieved for the prepared carbon material with excellent doping effect, such as high doping amount and numerous defects. During pyrolysis process, the generated gases facilitated the exfoliation of carbon structure, resulting in a nanosheet-like morphology with large specific surface area, e.g., 852.75 m2 g−1 for NPCN-900 sample obtained at 900 °C. Benefiting from the structural modulation brought by N,P co-doping, typical sample of NPCN-900 presented excellent catalytic performance towards bisphenol AF (BPAF) degradation through PMS activation. An apparent reaction rate constant of 0.4115 min−1 was calculated under the investigated reaction conditions. Further studies indicated that 1O 2 , surface-bound •OH and SO 4 −• worked together in NPCN-900/PMS system for BPAF degradation. Graphitic N, pyrrolic N, C O groups, defect structure and the doped P atoms in NPCN-900 contributed to PMS activation. It was also important that the toxicity of BPAF solution could be preliminarily eliminated after treatment by NPCN-900/PMS system, which was verified by ecotoxicity assessments through ECOSAR program and green algae growth experiments. [Display omitted] • N,P-co-doped carbon (NPCN) was obtained using ATP as sole precursor. • NPCN possessed nanosheet-like structure with surprisingly high specific surface area. • NPCN could efficiently activate PMS, resulting in fast degradation of bisphenol pollutant. • Reactive sites on NPCN and reactive oxygen species generation process were investigated. • Preliminary detoxification of BPAF was realized by NPCN-900/PMS catalytic system. [ABSTRACT FROM AUTHOR]

Peroxymonosulfate (PMS) activation technology represents an efficient approach to generate reactive oxygen species for treating pharmaceutical pollutants, and the fabrication of effective catalysts is of great significance for PMS activation technology. In this study, iron-manganese (Fe-Mn) layered double oxides (LDO) with flaky structure formed by metal oxide nanoparticles were synthesized by coprecipitation-calcination method and used to activate oxidant PMS to generate reactive oxygen species so as to realize the degradation of sulfathiazole (STZ). Benefiting from the well-dispersed structure and synergistic effect between bimetallic oxides, about 90% of STZ (20 mg L−1) could be removed with the dosage of catalyst (LDO-400, 0.4 g L−1) and PMS (0.4 g L−1) in 40 min catalysis process. Quenching experiments and in-situ electron paramagnetic resonance (EPR) analysis revealed that radical pathways dominated by surface-bound SO 4 −• and •OH were involved in the removal of STZ in LDO-400/PMS system. Besides, EPR and linear sweep voltammetry (LSV) analysis indicated the non-radical pathways containing 1O 2 and electron transfer also contributed to STZ degradation. Five consecutive cycles were conducted to prove the stability and reusability of LDO-400. The intermediates in the STZ degradation process were identified to propose the STZ degradation pathways. Particularly, ecological structure-activity relationship (ECOSAR) predicted the relatively low ecological risk of LDO-400/PMS system for STZ degradation. This study not only proves the advantages of synergistic effect between bimetallic oxides, but also enriches the design strategy of environmental remediation. [Display omitted] • Fe-Mn layered double oxides were obtained by a coprecipitation-calcination method. • Fe-Mn layered double oxides effectively activated peroxymonosulfate for sulfathiazole removal. • SO 4 −•, •OH, 1O 2 and electron transfer contribute to sulfathiazole removal. • The redox cycles of well-dispersed Fe and Mn were crucial for peroxymonosulfate activation. • The degradation intermediates exhibited relatively low ecotoxicity compared with sulfathiazole. [ABSTRACT FROM AUTHOR]

• Achyranthoside D is effective in relieving ACLT-MMx-induced osteoarthritis in rats. • Achyranthoside D inhibits NLRP3 inflammasome-triggered inflammation in rats. • Achyranthoside D attenuates IL-1β-induced chondrocyte loss in vitro. • Achyranthoside D inhibits NLRP3 inflammasome-triggered inflammation in vitro. • Achyranthoside D exerts anti-osteoarthritis effects via targeting Wnt3a. Achyranthes bidentata Blume (A. bidentata) is a common Chinese herb used to treat osteoarthritis (OA). Achyranthoside D (Ach-D) is a glucuronide saponin isolated from A. bidentata. To assess the mechanisms of action of Ach-D and its effects on OA. The effects of Ach-D were evaluated in rats underwent anterior cruciate ligament transection (ACLT) with medial meniscectomy (MMx) and in interleukin (IL)-1β-induced chondrocytes. Histological changes in rat cartilage tissues were detected using Safranin O-Fast green and haematoxylin-eosin staining. Immunohistochemical staining, qRT-PCR, ELISA, immunoblotting, and immunofluorescence were conducted to examine cartilage degeneration-related and inflammation-related factor expression. CCK-8, LDH assay, and EdU staining were performed to detect chondrocyte death. Ach-D dose-dependently reduced the Osteoarthritis Research Society International (OARSI) scores, alleviated cartilage injury, and decreased the serum concentrations of CTX-II and COMP in ACLT-MMx models. Ach-D increased the expression levels of collagen II and aggrecan and decreased the levels of cartilage degeneration-related proteins, ADAMTS-5, MMP13, and MMP3, in rat cartilage tissues. Additionally, nod-like receptor protein 3 (NLRP3)-related inflammation was reduced by Ach-D, as shown by the significantly inhibited expression levels of NLRP3, ASC, GSDMD, IL-6, TNF-α, IL-1β, and IL-18 in rat cartilage tissues. In primary rat chondrocytes, Ach-D protected against IL-1β-induced viability loss and LDH release. Wnt3a is the target protein of Ach-D. Mechanistically, Ach-D alleviated OA by inhibiting Wnt signalling. ACH-D may reduce inflammation and cartilage degeneration by inhibiting the Wnt signalling pathway, thereby reducing OA. [Display omitted] [ABSTRACT FROM AUTHOR]

In this work, microorganism of Phanerochaete chrysosporium with iron-tolerating and accumulating abilities was cultivated and harvested as mycelial pellets, which could serve as a sustainable and environmental-friendly precursor for iron phosphide/N-doped biocarbon composite preparation. Through one-step pyrolysis process, the inherent Fe and P elements in mycelial pellet enabled the formation of well crystallized Fe 2 P particles, loading on N-doped biocarbon matrix. Benefiting from the porous structure, high specific surface area, N doping-induced defects and C O groups of biocarbon, as well as the good electron-donating property of Fe 2 P, the as-obtained Fe 2 P/BC composite performed well for bisphenol pollutant (e.g., BPAF) removal through peroxymonosulfate (PMS) activation. Specifically, almost complete BPAF removal was achieved within 30 min adsorption and 10 min catalysis process with an apparent reaction rate constant of 0.486 min−1. The good crystallinity and protective carbon layer wrapping on Fe 2 P enabled the wide pH adaptability and low iron leaching of Fe 2 P/BC in catalytic reaction. Inorganic anions and humic acid brought only slight inhibition for BPAF removal, which could be overcome by prolonging reaction time to 30 min. Further mechanism studies indicated that reactive oxygen species, e.g., SO 4 -•, •OH and 1O 2 were generated through both radical and non-radical pathways and contributed to BPAF degradation. After treatment by Fe 2 P/BC-PMS system, the total organic carbon (TOC) of original BPAF solution (20 mg L−1) was reduced by 51.6%. Fortunately, the residual degradation intermediate products showed much reduced ecotoxicity in both predicted (ECOSAR program) and experimental results (growth inhibition test using Raphidocelis subcapitata as ecological indicator). [Display omitted] • Fe-containing mycelial pellet served as sole precursor for Fe 2 P/BC composite preparation. • Both Fe 2 P particles and biocarbon matrix contributed to PMS activation. • Low iron leaching was observed in Fe 2 P/BC-PMS catalytic system. • BPAF degradation was dominated by 1O 2 , surface-bound SO 4 -• and •OH. • ECOSAR and growth inhibition test implied the detoxification of BPAF by Fe 2 P/BC-PMS system. [ABSTRACT FROM AUTHOR]

Photocatalysis represents an environmental-benign approach for organic pollutant treatment. Herein, a photocatalytic system composed of Ni x P/biocarbon composite as reactive center and erythrosine B (ErB) as sensitizer was constructed for the removal of sulfamethoxazole (SMX) antibiotic under visible light irradiation. Ni x P/biocarbon composites were fabricated via a facile impregnation-pyrolysis approach using baker's yeast as both phosphorus and carbon precursor. It was found that Ni x P with pure Ni 12 P 5 , almost pure Ni 2 P or mixed crystal phases could be obtained by simply adjusting Ni:P molar ratio in precursor and pyrolysis temperature. Interestingly, the variation of Ni x P crystal phases remarkably affected photocatalytic removal efficiency of SMX. The obtained Ni x P(1:4)− 900 sample with mixed phases of Ni 12 P 5 and Ni 2 P displayed excellent photodegradation performance with 98.71% removal efficiency for SMX (C 0 = 20 mg L−1) in ErB-sensitized photocatalytic system. Moreover, the reusability of Ni x P/biocarbon composite was confirmed by four consecutive runs. The slight loss of activity in recycle study could be fully recovered after thermal regeneration. Further investigation indicated that photo-generated electrons from excited ErB molecules could be transferred to Ni x P/biocarbon, triggering a series of reactions to form various reactive oxygen species (eg., •O 2 −, H 2 O 2 , •OH) for SMX degradation. The better photocatalytic activity of Ni x P mixed crystal phases should be ascribed to its faster electron transfer ability. Overall, this study provides useful guidance in terms of the development of transition metal phosphide and efficient photocatalytic system. [Display omitted] • Ni x P/biocarbon is fabricated using Ni2+ impregnated yeast as sole precursor. • Ni:P molar ratio in precursor and pyrolysis temperature affect the crystal phase of Ni x P. • Ni x P-ErB-Vis photocatalytic system is constructed for SMX removal. • Ni x P with mixed phases of Ni 12 P 5 and Ni 2 P shows better photocatalytic activity. • H 2 O 2 , •O 2 − and •OH generated from photocatalytic process dominate SMX degradation. [ABSTRACT FROM AUTHOR]

• An efficient photochemical system was constructed by light/jarosite/Oxalic acid. • In-situ produced reaction oxygen species were responsible for CAP degradation. • Jarosite showed excellent stability and reusability in photocatalysis system. • CAP degradation intermediates show little antibacterial activity. Rational selection of affordable catalyst and effective degradation process are significant for antibiotic-containing wastewater treatment. Herein, a photochemical catalytic system comprising of bio-synthesized jarosite and oxalic acid (Ox) was investigated for degradation of antibiotic chloramphenicol (CAP) under light irradiation. Benefiting from abundant reactive species including H 2 O 2 , OH, O 2 − produced in photochemical process, a 97.5 % removal efficiency of CAP was obtained within 40 min. Consecutive testing cycles indicated jarosite had excellent stability and reusability in photocatalytic system. Radical chain reaction induced by photosensitive Fe(III)-Ox complexes under light irradiation was suggested to be the main mechanism for CAP degradation. A few degradation intermediates were identified to propose the possible degradation pathways of CAP. Further investigation showed that the antibacterial activities of CAP solution towards Escherichia. coli ATCC 8739 and Staphylococcus. aureus ATCC 6538 were largely reduced after treatment by photochemical process. Typical operation parameters of light/jarosite/Ox system were also investigated. CAP degradation performance in actual water demonstrated the feasibility of light/jarosite/Ox process. Overall, the developed light/jarosite/Ox system possesses great potential for antibiotic-containing wastewater treatment. [ABSTRACT FROM AUTHOR]

Advanced oxidation processes (AOPs) based on peroxymonosulfate (PMS) activation have attracted increasing attention in recent years for organic pollutants removal. Herein, we put forward a facile method to form cobalt phosphide/carbon composite for PMS activation. Combining impregnation approach with pyrolysis treatment enabled the formation of Co 2 P/biochar composites using baker's yeast and Co2+ as precursors. The as-synthesized products exhibited excellent catalytic activity for sulfamethoxazole (SMX) degradation over the pH range 3.0–9.0 b y activating PMS. For example, 100% of SMX (20 mg L−1) removal was achieved in 20 min with catalyst dosage of 0.4 g L−1 and PMS loading of 0.4 g L−1. Near zero Co2+ leaching was observed during catalytic reaction, which remarkably lowered the toxic risk of transition metal ion in water. Meanwhile, the reusability of catalyst could be attained by thermal treatment. SMX degradation intermediates were identified by liquid chromatography-mass spectrometry (LC-MS), which facilitated the proposal of possible SMX degradation pathways. Ecological Structure Activity Relationships (ECOSAR) analysis indicated that SMX degradation intermediates may not pose ecological toxicity to the environment. Further investigation verified that Co 2 P/biochar composites could set off PMS activation not only for the degradation of SMX but also for other sulfonamides. In this study, we not only developed a facile method of utilizing environmental-benign biomass for transition metal phosphide/carbon composite formation, but also achieved highly efficient antibiotic elimination by PMS-based AOP. Image 1 • A facile impregnation-pyrolysis method is established to form Co 2 P/biochar composite. • Baker's yeast provides P and C element for Co 2 P/biochar formation. • Co 2 P/biochar performs well for PMS activation to degrade sulfonamide antibiotics. • Co2+ leaching in catalytic reaction is low. • Ecotoxicity of SMX and degradation intermediates is predicated by ECOSAR system. [ABSTRACT FROM AUTHOR]

Advanced oxidation processes based on carbon catalysis is a promising strategy possessing great potential for environmental pollution degradation. Herein, nitrogen-doped biochar nanosheets (NCS-x) were synthesized using a nitrogen-rich biomass (Candida utilis) as sole precursor. The involvement of environmental-friendly molten salt (NaCl and KCl) in pyrolysis process not only facilitated the exfoliation of biochar, but also favored the retention of N element in biochar. When applying as catalyst for peroxymonosulfate activation, the as-obtained NCS-6 exhibited outstanding performance in catalytic degradation of bisphenol A (BPA). A 100% removal efficiency was observed in 6 min with fast reaction kinetic (k = 1.36 min−1). Based on quenching test and in-situ electron paramagnetic resonance analysis, both radical pathway and non-radical pathway were suggested to be involved in BPA degradation, while singlet oxygen was identified as the dominant reactive oxygen species. Furthermore, the ecotoxicity evaluation using Chlorella vulgaris as ecological indicator indicated that BPA solution after degradation was less toxic than the original solution. It is expected that this green and facile strategy holds great promise for value-added conversion of nitrogen-rich biomass to highly efficient biochar nanosheets for environment remediation. Image 1 • N-doped biochar nanosheets were synthesized using nitrogen-rich biomass. • Molten salt system promoted the retention of N and transformation of graphite N. • NCS-6/PMS exhibited fast reaction kinetic (k = 1.36 min−1) for BPA degradation. • Low ecotoxicity of BPA solution after degradation toward microalgae growth. [ABSTRACT FROM AUTHOR]