Water pollution caused by an abusive discharge of dye-containing wastewater leads to serious ecological risks. Conventional wastewater treatment methods have shortcomings of incomplete degradation, long-time treatment and secondary pollution. For the first time, a rotational hydrodynamic cavitation reactor (RHCR) equipped with a conical rotor has been designed to enhance the ozonation process for effective degradation of pollutants. The effects of rotational speed, discharge voltage, gas flow rate, liquid flow rate and initial pH on methylene blue (MB) degradation were deeply investigated. The optimised conditions were initial pH = 9, rotational speed = 1800 rpm, discharge voltage = 9.3 kV, gas flow rate = 60 mL/min and liquid flow rate = 80 mL/min. With the integration of ozonation and cavitation in RHCR, the MB degradation efficiency reached 95.2%, which was 15.6% higher than that of the individual ozonation method. The degradation process was proven to track the first-order kinetic model, with the reaction rate and synergy index were 0.232 min-1 and 1.78, respectively. Through the quenching experiments, it can be confirmed that the contribution proportion of hydroxyl radical during degradation was increased by 8.7% due to the enhancement of cavitation. A required energy consumption of 74.7 kWh/order/m3 and a total expense of 8.7 $/m3 were calculated. The energy consumption of the RHCR was approximately 80% lower than that of the recently reported degradation system combining ozonation and cavitation, with total expense reduced by 52%. The findings of this work provide a new water treatment method and offered theoretical references for the design of RHCR.

Electrocatalytic coupled biofilter (EBF) technology organically integrates the characteristics of electrochemistry and microbial redox, providing ideas for effectively improving biological treatment performance. In this study, an EBF system was developed for enhanced degradation of cyclohexanone in contaminated water. Experimental results show that the system can effectively remove cyclohexanone in contaminated water. Under the optimal parameters, the removal rates of cyclohexanone, TP, NH4+-N and TN were 97.61 ± 1.31%, 76.31 ± 1.67%, 94.14 ± 2.13% and 95.87 ± 1.01% respectively. Degradation kinetics studies found that electrolysis, adsorption, and biodegradation pathways play a major role in the degradation of cyclohexanone. Microbial community analysis indicates that voltage can affect the structure of the microbial community, with the dominant genera shifting from Acidovorax (0 V) to Brevundimonas (0.7 V). Additionally, Acidovorax, Cupriavidus, Ralstonia, and Hydrogenophaga have high abundance in the biofilm and can effectively metabolize cyclohexanone and its intermediates, facilitating the removal of cyclohexanone. In summary, this research can guide the development and construction of highly stable EBF systems and is expected to be used for advanced treatment of industrial wastewater containing cyclohexanone.

Chlorinated volatile organic compounds (Cl-VOCs) have dramatically biotoxicity and environmental persistence due to the presence of chlorine atoms, seriously jeopardizing ecological security and human health. Dichloromethane (DCM) as a model pollutant, is widely applied in solvents, extractants and cleaning agents in the pharmaceutical, chemical and food industries. In this study, highly biocompatible and conductive carbon cloth-titanium nitride-polyaniline (CC-TiN-PANI) bioelectrodes were obtained for DCM degradation in microbial electrolysis cell (MEC). The good adhesion of TiN and PANI on the electrode surface was demonstrated. The degradation kinetics were fitted by the Haldane model, compared to the CC bioelectrode (0.8 h-1), the proportion of maximum degradation rates to half-saturation concentration (Vmax/Km) of CC-TiN (1.4 h-1) and CC-TiN-PANI (2.2 h-1) bioelectrodes were enhanced by 1.8 and 2.8 times, respectively. Microbial community structure analysis illuminated that the dominant genera on the biofilm were Alicycliphilus and Hyphomicrobium, and the abundance was enhanced significantly with the modification of TiN and PANI. The dechlorination of DCM to formaldehyde could be catalyzed by DCM dehalogenase (DcmA) or by haloalkane dehalogenase (DhlA). And further oxidized to formate: 1) direct catalyzed by formaldehyde dehydrogenase (FdhA); 2) conjugated with glutathione by S-(hydroxymethyl)-glutathione synthase (Gfa), S-(hydroxymethyl)-glutathione dehydrogenase (FrmA) and S-formyl-glutathione hydrolase (FrmB); 3) conjugation with tetrahydrofolate (H4F) and/or tetrahydromethanopterin.

Pesticide residues and microplastics (MPs) in agricultural soils are two major concerns for soil health and food safety. The degradation of chlorpyrifos (CPF), an organophosphorus pesticide, releases phosphates. This process may be affected by the presence of MPs in the soil. The combination of CPF and MPs presence in the soil may thus produce interaction effects that alter the soil phosphorus (P) balance. This study explores the degradation pathways of CPF (6 mg kg-1, 12 mg kg-1 of CPF addition) in soils with different levels of polylactic acid MPs (PLA-MPs) (0.0 %, 0.1 %, 0.5 %, 1.0 % w/w), and analyzes soil P fractions and phosphatase enzyme activities to investigate soil P bioavailability under different treatments. Results show that the degradation of CPF fits to a first-order decay model, with half-lives (DT50) ranging from 11.0 to 14.8 d depending on PLA-MPs treatment. The concentration of its metabolite 3, 5, 6-trichloropyridine 2-phenol (TCP) reached a peak of 0.93-1.67 mg kg-1 within 7-14 days. Similarly, the degradation of CPF led to a significant transient increase in P bioavailability within 3-7 days (p < 0.05), with a peak range of 22.55-26.01 mg kg-1 for Olsen-P content and a peak range of 4.63-6.76 % for the proportions of available P fractions (H2O-P+NaHCO3-P+NaOH-P), before returning to prior levels (Olsen-P: 11.28-19.52 mg kg-1; available soil P fractions: 4.15-5.61 %). CPF degradation (6 mg kg-1) was significantly inhibited in soil with 1.0 % PLA-MPs addition. The effects of MPs and CPF on soil P fractions occur at different time frames, implying that their modes of action and interactions with soil microbes differ.

This study investigated degradation behaviors of a nonsteroidal anti-inflammatory drug Nabumetone (NMT) and its major metabolite 6-methoxy-2-naphthylacetic acid (MNA) in the coupling process of ultraviolet and monochloramine (UV/NH2Cl). The second-order rate constants of the contaminants reacting with reactive radicals (HO•, Cl•, Cl2•⁻, and CO3•⁻) were determined by laser flash photolysis experiments. HO• and Cl• contributed predominantly with 52.3% and 21.7% for NMT degradation and 60.8% and 22.3% for MNA degradation. The presence of chlorides retarded the degradation of NMT, while promoted the destruction of MNA, which was ascribed to the photosensitization effects of MNA under UV irradiation. Density functional theory (DFT) calculations revealed that radical adduct formation (RAF) was dominant pathway for both HO• and Cl• reacting with the contaminants, and hydrogen atom transfer (HAT) preferred to occur on side chains of NMT and MNA. NMT reacted with NO2• through single electron transfer (SET) with the second-order rate constant calculated to be 5.35 × 107 (mol/L)-1 sec-1, and the contribution of NO2• was predicted to be 13.0% of the total rate constant of NMT in pure water, which indicated that NO2• played a non-negligible role in the degradation of NMT. The acute toxicity and developmental toxicity of NMT were enhanced after UV/NH2Cl treatment, while those of MNA were alleviated. The transformation products of both NMT and MNA exhibited higher mutagenicity than their parent compounds. This study provides a deep understanding of the mechanism of radical degradation of NMT and MNA in the treatment of UV/NH2Cl.

Macrophytes are crucial in maintaining the equilibrium of aquatic ecosystems. However, the pattern of macrophyte-derived caffeic acid (CA) release under heavy metal stress is yet to be fully understood. More importantly, due to its functional groups, CA may be a precursor to the formation of disinfection by-products, posing threats to water ecology and even safety of human drinking water. This study analyzed the responses of CA released by Vallisneria natans (V. natans) and Pistia stratiotes (P. Stratiotes) when exposed to Cu2+ and Mn2+ stress. Additionally, the CA levels in two constructed wetland ponds were detected and the degradation kinetics of CA during chlorination were investigated. Results indicated that CA occurred in two constructed wetland ponds with the concentrations of 44.727 μg/L (planted with V. natans) and 61.607 μg/L (planted with P. Stratiotes). Notably, heavy metal stress could significantly affect CA release from V. natans and P. Stratiotes. In general, under Cu2+ stress, V. natans secreted far more CA than under Mn2+ stress, the level could reach up to 435.303 μg/L. However, compared to V. natans, P. Stratiotes was less affected by Cu2+ and Mn2+ stress, releasing a maximum CA content of 55.582 μg/L under 5 mg/L Mn2+ stress. Aquatic macrophytes secreted more CA in response to heavy metal stresses and protected macrophytes from harmful heavy metals. CA degradation followed the pseudo first-order kinetics model, and the chlorination of CA conformed to a second-order reaction. The reaction rate significantly accelerated as NaClO, pH, temperature and Br- concentration increased. A new pathway for CA degradation and a new DBP 2, 2, 3, 3-tetrachloropropanal were observed. These findings pointed at a new direction into the adverse effect of CA, potentially paving the way for new strategies to solve drinking water safety problems.

Thermal stability and antioxidant ability of γ-oryzanol in oil have been widely studied. However, further research is needed to explore its thermal degradation products and degradation pathways. The thermal degradation products of γ-oryzanol in stripped soybean oil were identified and quantified by employing high-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS) during heating at 180 °C. The results revealed that γ-oryzanol undergoes ester bond cleavage to form trans-ferulic acid and free sterols, and trans-ferulic acid generated intermediate compound 4-vinylguaiacol, which ultimately generated vanillin. Analysis of kinetic and thermodynamic parameters revealed the thermal stability ranking of the four components of γ-oryzanol as follows: CampFA > CAFA > 24MCAFA > SitoFA. Furthermore, γ-oryzanol exhibited superior antioxidant activity at lower temperatures. The results of this study provide a theoretical basis for a better understanding of the thermal stability and antioxidant properties of γ-oryzanol in oil under thermal oxidation conditions.

As reported, the persistent toxic and harmful pollutant bisphenol A (BPA) from industrial emissions has been consistently found in aquatic environments inhabited by humans. Periodate (PI)-based advanced oxidation processes (AOPs) have been employed to degrade BPA, although activating PI proves more challenging compared to other oxidants. A novel nano iron metal catalyst, sulfided nanoscale iron-nickel bimetallic nanoparticle supported on biocarbon (S-(nFe0-Ni)/BC) was synthesized and utilized to activate PI for the removal of BPA. The morphology, structure, and composition of S-(nFe0-Ni)/BC were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy-energy dispersive spectrometer (SEM-EDS), and fourier-transform infrared spectrum (FTIR). The catalyst demonstrates an excellent ability to activate PI, achieving a BPA removal efficacy of 86.4%, accompanied by a 33% reduction in total organic carbon (TOC) in the {S-(nFe0-Ni)/BC}/PI system. BPA degradation exhibited a significant change at the 5-min mark. In the first stage (0-5 min), nonlinear dynamic fitting research, combined with scavenging experiments, unveiled the competitive degradation of pollutants primarily driven by iodate radical ( IO 3 · ), singlet oxygen 1 O 2 , and hydroxyl radical ( · OH ). The competitive dynamics aligned with the ExpAssoc model. The contribution rates of different active species during the second stage (5-120 min) were calculated. The contributions of main species to BPA removal follow the order of IO 3 · > 1 O 2 > · OH throughout the entire process. The influence of various parameters, such as the dosage of S-(nFe0-Ni)/BC, initial PI concentration, BPA concentration, pH, temperature, and the presence of coexisting anions, was also examined. Finally, a plausible reaction mechanism in the system is proposed, suggesting that the {S-(nFe0-Ni)/BC}/PI system involves a heterogeneous synergistic reaction occurring primarily on the surface of S-(nFe0-Ni)/BC. Therefore, this study proposes a promising approach for PI-based AOPs to degrade organic pollutants, aiming to mitigate the irreversible harm caused by such pollutants to organisms and the environment.

A green approach of Desmodesmus sp. to Achromobacter pulmonis (1:1) coculture ratios was optimized to improve the removal efficiency of dibutyl phthalate (DBP) from simulated wastewater. High DBP resistance bacterial strains and microalgae was optimized from plastic contaminated water and acclimation process respectively. The influence of various factors on DBP removal performance was comprehensively investigated. Highest DBP removal 93 % was recorded, when the ratios algae-bacteria 1:1, with sodium acetate, pH-6, shaking speed-120 rpm and lighting periods L:D-12:12. Enough nutrient (TN/TP/TOC) availability and higher protein-108 mg/L and sugar-40 mg/L were observed in presences of 50 mg/L DBP. The degradation and sorption were calculated 81,12; 27,39 & 43,12 % in algae-bacteria, only algae and only bacteria system respectively. The degradation kinetics t1/2 3.74,22.15,12.86 days were evaluated, confirming that algae-bacteria effectively degrade the DBP. This outcome leading to promote a green sustainable approach to remove the emerging contamination from wastewater.

This study investigated degradation kinetics of five selected organic micropollutants (OMPs) present in poultry litter (namely: sulfadiazine, tetracycline, and doxycycline hyclate (antibiotics); estrone and 17-β-estradiol (hormones)) during hydrothermal carbonization (HTC) treatment as the temperature stepwise increased to 250 °C. All five pure OMPs were completely degraded before 250 °C was reached during the HTC process. Nevertheless, presence of poultry litter slowed down the degradation of OMPs. Through elemental mass balance calculation, it is noted that after 15 min (temperature less than 137 °C), 69-82% of organic carbon and 50-66% of organic nitrogen initially consisting part of the target antibiotics were fully mineralized. Both HTC filtrates and hydrochars obtained from poultry litter inhibited Escherichia coli and Bacillus subtilis growth. A combination of high salinity, high nutrients, dissolved organic carbon, and other ions in the filtrate as well as the adsorption of OMPs on hydrochars were probably the reason for the high toxicity.