In situ activation of peroxymonosulfate with bioelectricity for sulfamethoxazole sustainable removal.

Conventional electrochemical activation of peroxymonosulfate (PMS) is not very cost-effective and practical by the excessive input of energy. The electricity generated by photosynthetic microalgae fuel cells (MFCs) is utilized to activate PMS, which would achieve the combination of green bioelectricity and advanced oxidation processes for sustainable pollutants degradation. In this study, a novel dual-chamber of MFCs was constructed by using microalgae as anode electron donor and PMS as cathode electron acceptor, which was operating under both close-circuit and open-circuit conditions. Under close-circuit condition, 1-12 mM PMS in cathode was successfully in situ activated, where 32.00%-99.83% of SMX was removed within 24 h, which was about 1.21-1.78 times of that in the open-circuit of MFCs. Meanwhile, a significant increase in bioelectricity generation in MFCs was observed after the accumulation of microalgae biomass (4.65-5.37 mg/L), which was attributed to the efficient electron separation and transfer. Furthermore, the electrochemical analysis demonstrated that SMX or its products were functioned as electronic shuttles, facilitating the electrochemical reaction and altering the electrical capacitance. The quenching experiments and voltage output results reflected that complex active radical (SO4⋅-, ⋅OH, and 1O2) were involved in SMX removal. Seven degradation products of SMX were detected and S-N bond cleavage was the main degradation pathway. Predicted toxicity values calculated by ECOSAR program showed that all the products were less toxic or nontoxic. Finally, the density functional theory (DFT) calculations revealed that the O and N atoms on SMX were more susceptible to electrophilic reactions, which were more vulnerable to be attacked by reactive species. This study provided new insights into the activation of PMS by bioelectricity for SMX degradation, proposing the mechanisms for PMS activation and degradation sites of SMX.

Spatiotemporal distribution, sources apportionment and ecological risks of PAHs: a study in the Wuhan section of the Yangtze River.

This study investigated the sources, contamination and ecological risks of polycyclic aromatic hydrocarbons (PAHs) based on their spatiotemporal distribution in aquatic environment in the Wuhan section of the Yangtze River (WYR). The fugacity ratio evaluation indicated that sediment was secondary release sources of two- and three-ring PAHs and sinks of four- and five-ring PAHs. The total concentrations of PAHs (Σ16PAHs) ranged from 2.51 to 102.5 ng/L in water with the dominant contribution of 47.8% by two-ring PAHs. Σ16PAHs in sediments varied from 5.90 to 2926 ng/g with the contribution of 35.4% by four-ring PAHs. The higher levels of PAHs occurred around developed industrial areas during the wet season, which was related to local industrial emissions and influenced by rainfall/runoff. Annual flux of Σ16PAHs was estimated of 28.77 t. The PMF model analysis revealed that petroleum and industrial emissions were the dominant sources in water accounting for 58.5% of the total pollution, although traffic emission was the main source for sediment accounting for 44.6%. Risk assessments showed that PAHs in water were at low risks, whereas about 44% of the sediments were identified as medium risks. Therefore, energy structure adjustment and further implement of regulation and monitoring are necessary to reduce PAH emissions.

Synergistic heat/UV activated persulfate for the treatment of nanofiltration concentrated leachate.

Nanofiltration concentration leachate is a high concentration organic wastewater with low biodegradability and high toxicity. To explore the feasibility of a combined Heat/UV activated persulfate process on nanofiltration concentrated leachate, the effects of persulfate concentration, initial solution pH before reaction, UV-lamp power and reaction temperature on the removal of organic pollutant were systematically investigated. Results indicated that the maximum rate of chemical oxygen demand (COD), ammonia-nitrogen (NH3-N) and absorbance of organic matter under UV light at 254 nm (UV254) removal from the leachate were 65.4%, 51.4% and 98.1%, respectively, at a persulfate concentration of 18 g L-1, initial solution pH before reaction of 9.0, UV-lamp power of 60 W and temperature of 80 °C. The results of three-dimensional fluorescence and UV254 showed that the removal rates of humic substances contained in the nanofiltration concentrated leachate were over 98%. In addition, the results of free radical scavenging showed that hydroxyl radicals were dominant under alkaline conditions. The results of this study demonstrated that coupling heat and ultraviolet activated persulfate oxidation is a promising technique for the treatment of nanofiltration concentrated leachate.

Iron/zinc and phosphoric acid modified sludge biochar as an efficient adsorbent for fluoroquinolones antibiotics removal.

Iron/zinc (Fe/Zn), phosphoric acid (H3PO4) or in combination (Fe/Zn + H3PO4) modified sludge biochar (SBC) were prepared and tested in this study to adsorb fluoroquinolones antibiotics including ciprofloxacin (CIP), norfloxacin (NOR) and ofloxacin (OFL) from water. Fe/Zn + H3PO4-SBC had an increased surface area (SBET), total pore volume (Vtot), mesoporous volume (Vmes), pore diameter (Dp) and oxygen-containing functional groups. It exhibited superior adsorption performance for CIP, NOR and OFL with the maximum adsorption amount of 83.7, 39.3, 25.4 mg g-1, respectively. Pseudo-second kinetic and Freundlich isotherm model presented the better fitting. The results of models and characterization analysis in combination indicated that physisorption and chemisorption, including pore filling, hydrogen bonding, π-π interaction, electrostatic interaction and functional groups complexation on a heterogeneous surface were the dominant process and mechanism. Liquid film diffusion was the main rate-limiting step. The adsorption process of CIP, NOR and OFL onto Fe/Zn + H3PO4-SBC were a spontaneous endothermic process. This study demonstrated that Fe/Zn + H3PO4 modified SBC exhibited high adsorption capacity, which was a promising adsorbent for fluoroquinolones as well as for other antibiotics effective removal from waters.

Spatiotemporal variation, fluxes and risk evaluation of neonicotinoid insecticides within the midsection of Yangtze River, China: An exploration as ecological protection threshold.

Neonicotinoid insecticides (NNIs) have attracted global concern due to its extensive use in agricultural activities and their potential risks to the animal and human health, however, there is limited knowledge on the regional traits and ecological risks of NNIs in the aquatic environments. We herein investigated the occurrence of NNIs within the midsection of Yangtze River in China, offering the inaugural comprehensive report on NNIs within this region. In this study, eleven NNIs were analyzed in 108 river water and sediment samples from three seasons (normal, dry and wet season). We detected a minimum of seven NNIs in the water and four NNIs in the sediment, with total concentrations ranging from 12.33 to 100.5 ng/L in water and 0.08-5.68 ng/g in sediment. The levels of NNIs in both river water and sediment were primarily influenced by the extent of agricultural activities. The estimated annual load of NNIs within the midsection of Yangtze River totaled 40.27 tons, April was a critical contamination period. Relative potency factor (RPF) analysis of the human exposure risk revealed that infants faced the greatest exposure risk, with an estimated daily intake of 11.27 ng kg-1∙bw∙d-1. We established the acute and chronic thresholds for aquatic organisms by employing the Species Sensitive Distribution (SSD) method (acute: 384.1 ng/L; chronic: 168.9 ng/L). Based on the findings from this study, 33% of the river water samples exceeded the chronic ecological risks thresholds, indicating the urgent need for intervention programs to guarantee the safety of the river for aquatic life in the Yangtze River Basin.

Facile synthesis of ball-milling and oxalic acid co-modified sludge biochar to efficiently activate peroxymonosulfate for sulfamethoxazole degradation: 1O2 and surface-bound radicals.

A novel approach of ball milling and oxalic acid was employed to modify sludge-based biochar (BOSBC) to boost its activation performance for peroxymonosulfate (PMS) towards efficient degradation of sulfamethoxazole (SMX). 98.6% of SMX was eliminated by PMS/BOSBC system within 60 min. Furthermore, PMS/BOSBC system was capable of maintaining high removal rates for SMX (>88.8%) in a wide pH range from 3 to 9, and displayed a high tolerance to background electrolytes including inorganic ions and humic acid (HA). Quenching experiments, electron paramagnetic resonance (EPR) analysis, in-situ Raman characterization and PMS decomposition experiments confirmed that the non-radicals of 1O2 and surface-bound radicals were the main contributors to SMX degradation by PMS/BOSBC system. The results of ecotoxicity assessment illustrated that all transformed products (TPs) generated in PMS/BOSBC system were less toxic than that of SMX. After five reuse cycles, PMS/BOSBC system still maintained a high removal rate for SMX (77.8%). Additionally, PMS/BOSBC system exhibited excellent degradation performance for SMX in various real waters (Yangtze River water (76.5%), lake water (74.1%), tap water (86.5%), and drinking water (98.1%)). Overall, this study provided novel insights on non-metal modification for sludge-based biochar and non-radical mechanism, and offered a feasible approach for municipal sludge disposal.

One-pot preparation of layered double oxides-engineered biochar for the sustained removal of tetracycline in water.

Tetracycline (TC) and sugarcane bagasse had both exerted enormous strain on environmental security. In this work, new composite adsorbent designed by impregnating bio-waste bagasse with magnesium-aluminum layered double oxides (BC-MA) was innovatively brought forward for TC removal. Benefiting from the abundant adsorption sites supplied by developed pores structure (0.308 cm3·g-1), enlarged surface area (256.8 m2·g-1) and reinforced functional groups, the maximum adsorption amount of BC-MA for TC reached 250.6 mg g-1. Moreover, BC-MA displayed desirable adsorption capacity in diverse water environments coupled with excellent sustainable regeneration ability. The absorption process of TC by BC-MA was spontaneous and endothermic, and the pivotal rate-limiting stage pertained to intraparticle diffusion. The mechanisms proposed here mainly concerned π-π interactions, pore filling, complexation and hydrogen bonding. These findings suggested that the synthesis of modified biochar from bagasse would offer new opportunities for simultaneous waste resource reuse and water pollution control.

Ball milling and acetic acid co-modified sludge biochar enhanced by electrochemistry to activate peroxymonosulfate for sustainable degradation of environmental concentration neonicotinoids.

Neonicotinoids pose potential serious risks to human health even at environmental concentration and their removal from water is considered as a great challenge. A novel ball milling and acetic acid co-modified sludge biochar (BASBC) was the first time synthesized, which performed superior physicochemical characteristics including larger surface area, more defect structures and functional groups (e.g., CO and -OH). Electrochemistry was introduced to enhance BASBC for peroxymonosulfate (PMS) activation (E/BASBC/PMS) to degrade environmental concentration neonicotinoids (e.g., imidacloprid (IMI)). The degradation efficiency of IMI was 95.2% within 60 min (C0 (PMS)= 1 mM, E= 25 V, m (BASBC)= 10 mg). Solution pH and anionic species/concentrations were critical affecting factors. The scavenging and electron paramagnetic resonance experiments suggested that •OH and 1O2 were the dominant reactive oxygen species contributing to IMI degradation. Three degradation pathways were proposed and pathway Ⅲ was the main one. 86.1% of IMI were mineralized into non-toxic CO2 and H2O, and others were converted into less toxic intermediates. Also, E/BASBC/PMS system achieved the sustainable degradation of IMI in the cycle experiments. Additionally, it exhibited excellent degradation performance for other three typical neonicotinoids (96.6% of thiacloprid (THI), 96.5% of thiamethoxam (THX) and 82.6% of clothianidin (CLO)) with high mineralization efficiencies (87.8% of THI, 90.5% of THX and 75.4% of CLO).

Removal of cadmium in aqueous solutions using a ball milling-assisted one-pot pyrolyzed iron-biochar composite derived from cotton husk.

A novel iron-biochar composite adsorbent was produced via ball milling-assisted one-pot pyrolyzed BM-nZVI-BC 800. Characterization proved that nano zero valent iron was successfully embedded in the newly produced biochar, and the nZVI payload was higher than that of traditional one-pot pyrolyzed methods. BM-nZVI-BC 800 provided a high adsorption performance of cadmium reaching 96.40 mg·g-1 during batch testing. Alkaline conditions were beneficial for cadmium removal of BM-nZVI-BC 800. The pseudo-second-order kinetic model and Langmuir isotherm fitted better, demonstrating that the Cd adsorption on the BM-nZVI-BC 800 was a chemical and surface process. The intraparticle diffusion controlled the adsorption of BM-nZVI-BC 800. The physisorption dominated by high specific surface area and mesoporous structure was the primary mechanism in the removal of cadmium, though electrostatic attraction and complexation also played a secondary role in cadmium adsorption. Compared to adsorbents prepared by more traditional methods, the efficiencies of the ball milling-assisted one-pot pyrolyzed method appears superior.

Annual flux estimation and source apportionment of PCBs and PBDEs in the middle reach of Yangtze River, China.

This work is the first time to investigate the annual flux, spatiotemporal changes and sources of PCBs and PBDEs in water and sediment from the middle reach of Yangtze River (Wuhan, China), which was particularly based on the monthly monitoring data in a one-year-round study. The concentrations of PCBs and PBDEs in water were

Efficient degradation of sulfamethoxazole in various waters with peroxymonosulfate activated by magnetic-modified sludge biochar: Surface-bound radical mechanism.

First time, this study synthesized a magnetic-modified sludge biochar (MSBC) as an activator of peroxymonosulfate (PMS) to eliminate sulfamethoxazole (SMX). The removal efficiency of SMX reached 96.1% at t = 60 min by PMS/MSBC system. The larger surface area and magnetic Fe3O4 of MSBC surface enhanced its activation performance for PMS. The PMS decomposition, premixing and reactive oxygen species (ROS) identification experiments combined with Raman spectra analysis demonstrated that the degradation process was dominated by surface-bound radicals. The transformed products (TPs) of SMX and the main degradation pathways were identified and proposed. The ecotoxicity of all TPs was lower than that of SMX. The magnetic performance was beneficial for its reuse and the removal efficiency of SMX was 83.3% even after five reuse cycles. Solution pH, HCO3- and CO32- were the critical environmental factors affecting the degradation process. MSBC exhibited environmental safety for its low heavy metal leaching. PMS/MSBC system also performed excellent removal performance for SMX in real waters including drinking water (88.1%), lake water (84.3%), Yangtze River water (83.0%) and sewage effluent (70.2%). This study developed an efficient PMS activator for SMX degradation in various waters and provided a workable way to reuse and recycle municipal sludge.

Estimating Sources, Fluxes, and Ecological Risks of Antibiotics in the Wuhan Section of the Yangtze River, China: A Year-Long Investigation.

To our knowledge, ours is the first study to investigate the annual fluxes, environmental fate, and ecological risks of five categories of antibiotics from the Wuhan section of the Yangtze River (China). All the 24 antibiotics we tested for were detected in water, with total concentrations of 17.11-867.2 ng/L (mean: 63.69 ng/L), and 19 antibiotics were detected in sediment, at 0.02-287.7 ng/g (mean: 16.54 ng/g). Sulfonamides, amphenicols, and macrolides were the three most prominent antibiotic classes in water, and fluoroquinolones were the most prominent in sediment. Farming activities (animal husbandry and aquaculture) are proposed as the largest contributors to antibiotic pollution in the Wuhan section of the Yangtze River according to the Unmix model, followed by municipal wastewater and mixed sources. Higher pollution levels were observed downstream (combined discharge of these sources). Monthly monitoring data (12 months) were used to estimate antibiotic annual fluxes, with 101.5 t (uncertainty: 5.6%) in the Wuhan section of the Yangtze River. Risk assessments showed that erythromycin, clarithromycin, and azithromycin posed medium and high ecological risks and were found in 9%-35% and 1.8%-3.7% of all water samples, respectively; enrofloxacin, clarithromycin, azithromycin, florfenicol, and thiamphenicol posed medium resistance risks in 1.9%-16.7% of waters in the Wuhan section of the Yangtze River. Our results have filled data gaps on antibiotic sources, annual fluxes, and resistance risk in the Wuhan section of the Yangtze River and demonstrated the importance of further management of antibiotic use in the studied areas. Environ Toxicol Chem 2023;42:605-619. © 2022 SETAC.

Fe-Al bimetallic oxides functionalized-biochar via ball milling for enhanced adsorption of tetracycline in water.

The clusters formed by modified materials on its surface makes the application of functionalized biochars in adsorption face a great challenge. Here, a facile ball milling technology was innovatively proposed to tailor Fe-Al oxides-laden bagasse biochar to fabricate a novel adsorbent (BMFA-BC). Benefited from the increased exposure of Fe-Al oxides and, more importantly, enhanced functional groups by ball milling, the adsorption capacity of BMFA-BC for aqueous tetracycline reached up to 116.6 mg g-1 at 298 K. And the adsorption performance was temperature-dependent. Characterization analysis, batch sorption (thermodynamics, kinetics, isotherms, chemical factors) as well as data modeling illustrated that this superior adsorption ability could be attributed to π-π conjugation, H-bonding, complexation as well as pore filling. BMFA-BC displayed good adsorption capacity in multiple aqueous environments. The excellent regeneration ability, magnetic susceptibility ensured its viability for sustainable pollutants removal. These superiorities revealed that BMFA-BC was a suitable sorbent for antibiotics elimination.

Molten-salts assisted preparation of iron-nitrogen-carbon catalyst for efficient degradation of acetaminophen by periodate activation.

Highly efficient and stable heterogeneous catalysts were desired to activate periodate (PI) for sustainable pollution control. Herein, iron-nitrogen-carbon catalyst was synthesized using a facile molten-salts mediated pyrolysis strategy (denoted as FeNC-MS) and employed to activate PI for the degradation of acetaminophen (ACE). Compared with iron-nitrogen-carbon catalyst prepared by direct pyrolysis method (marked as FeNC), FeNC-MS exhibited superior catalytic activity due to its large specific surface area (1600 m2 g-1) and the abundance of FeNx sites. The batch experiments revealed that FeNC/PI process achieved 37 % ACE removal within 20 min, while ACE removal in FeNC-MS/PI process was 98 % under the identical conditions. Integrated with electron paramagnetic resonance tests, quenching experiments, chemical probe identification, and electrochemical experiments, we demonstrated that FeNC-MS-PI complexes-mediated electron transfer was the predominant mechanism for the oxidation of ACE. Further analysis disclosed that FeNx sites in FeNC-MS were the main active sites for the activation of PI. Additionally, FeNC-MS/PI process exhibited significant resistance to humic acid and background electrolyte, and avoided the secondary pollution imposed by Fe leaching. The possible degradation pathways of ACE were proposed. The germination experiments of lettuce seeds showed that the ecotoxicity of ACE solution was significantly reduced after treatment with FeNC-MS/PI process. Overall, this study provided a facile strategy for the synthesis of efficient iron-nitrogen-carbon catalysts and gained fundamental insight into the mechanism of PI activation by iron-nitrogen-carbon catalysts for pollutants degradation.

Insights on ball milling enhanced iron magnesium layered double oxides bagasse biochar composite for ciprofloxacin adsorptive removal from water.

Both ciprofloxacin (CIP) and sugarcane bagasse have brought enormous pressure on environmental safety. Here, an innovative technique combining Fe-Mg-layered double oxides and ball milling was presented for the first time to convert bagasse-waste into a new biochar adsorbent (BM-LDOs-BC) for aqueous CIP removal. The maximum theoretical adsorption capacity of BM-LDOs-BC reached up to 213.1 mg g-1 due to abundant adsorption sites provided by well-developed pores characteristics and enhanced functional groups. The results of characterization, data fitting and environmental parameter revealed that pore filling, electrostatic interactions, H-bonding, complexation and π-π conjugation were the key mechanisms for CIP adsorptive removal. BM-LDOs-BC exhibited satisfactory environmental safety and outstanding adsorption capacity under various environmental situations (pH, inorganic salts, humic acid). Moreover, BM-LDOs-BC possessed excellent reusability. These superiorities illustrated that BM-LDOs-BC was a promising adsorbent and created a new avenue for rational placement of biowaste and high-efficiency synthesis of biochar for antibiotic removal.

Efficient removal of Imidacloprid and nutrients by algae-bacteria biofilm reactor (ABBR) in municipal wastewater: Performance, mechanisms and the importance of illumination.

Neonicotinoids, such as Imidacloprid (IMI), are frequently detected in water and wastewater, posing a threat on both the environment and the health of living things. In this work, a novel algae-bacteria biofilm reactor (ABBR) was constructed to remove IMI and conventional nutrients from municipal wastewater, aiming to explore the removal effect and advantage of ABBR. Results showed that ABBR achieved 74.9% removal of IMI under 80 µmol m-2·s-1 light, higher than photobioreactor (PBR) without biofilm (61.2%) or ABBR under 40 µmol m-2·s-1 light (48.4%) after 16 days of operation. Moreover, it also showed that ABBR allowed a marked improvement on the removal of total dissolved nitrogen (TDN), total dissolved phosphorus (TDP) and soluble chemical oxygen demand (sCOD). ABBR showed different IMI removal efficiencies and bacterial communities under different light conditions, indicating that light played an important role in driving ABBR. The merits of ABBR are including (i) ABBR showed rapid pollutant removal in a short time, (ii) in ABBR, stable consortiums were formed and chlorophyll content in effluent was very low, (iii) compared with PBR, degradation products in ABBR showed lower biological toxicity. Our study highlights the benefits of ABBR on IMI removing from municipal wastewater and provides an effective and environment-friendly engineering application potential of IMI removal.

Understanding the nonradical activation of peroxymonosulfate by different crystallographic MnO2: The pivotal role of MnIII content on the surface.

Manganese oxide-activated persulfate plays a critical role in water purification and in situ chemical oxidation processes, but the underlying mechanism needs to be further revealed. Herein, the detailed mechanism of MnO2 with various crystallographic structures (α-, ß-, γ-, and δ-MnO2) towards peroxymonosulfate (PMS) activation was investigated. PMS activated by tunnel structured α-, ß-, and γ-MnO2 showed higher acetaminophen (ACE) removal than layer structured δ-MnO2 with the removal efficiency following an order of α-MnO2 (85%) ≈ Î³-MnO2 (84%) > ß-MnO2 (65%) > Î´-MnO2 (31%). Integrated with chemical quenching experiments, electron paramagnetic resonance, Raman spectra, X-ray photoelectron spectroscopy, and Langmuir-Hinshelwood model on kinetic data, both surface-bound PMS complexes and direct oxidation by surface manganese species (Mn(Ⅳ, Ⅲ)(s)) were disclosed as the dominant oxidation mechanism for ACE degradation in α-, ß-, and γ-MnO2/PMS, which were rarely observed in previous reports. Moreover, the catalytic activity of α-, ß-, and γ-MnO2 was positively correlated to the MnIII(s) content on the catalyst surface. Higher content of MnIII(s) would stimulate the generation of more oxygen vacancies, which was conducive to the adsorption of PMS and the formation of reactive complexes. Overall, this study might provide deeper insight into the nonradical activation mechanism of PMS over different crystallographic MnO2.

Efficient adsorptive removal of fluoroquinolone antibiotics from water by alkali and bimetallic salts co-hydrothermally modified sludge biochar.

Fluoroquinolones are one of most commonly used antibiotics for preventing and treating bacterial infections and their unsatisfactory removal by conventional wastewater treatment technology have aroused widespread attention. A novel adsorbent of KMSBC was the first time synthesized and tested to adsorb three typical fluoroquinolone antibiotics of CIP, NOR and OFL from water. The characterization analysis showed that KMSBC possessed the superior porous structure, abundant functional groups and greater graphitic degree. Together with kinetics, isotherms, thermodynamics and critical factors (e.g., biochar dose, reaction time/temperature, fluoroquinolone antibiotics concentration, pH, co-existing ionic strength and HA concentration) analysis suggested that pore filling, π-π conjugation, H-bonding and electrostatic interaction were the key mechanisms for fluoroquinolone antibiotics adsorption by KMSBC. KMSBC exhibited the optimum adsorption performance at pH = 5 despite the adsorbates. The maximum adsorption capacity of KMSBC for CIP, NOR and OFL were 49.9, 55.7 and 47.4 mg/g at 25 °C, respectively. Also, KMSBC exhibited the good magnetic sensitivity and stability with the leaching concentrations of Fe were far below than environmental limit (GB5749-2006) at various pH (from 3 to 12), ionic strength and HA concentrations. Additionally, KMSBC performed a stable sustainable adsorption performance in recycles by NaOH regeneration. Thus, KMSBC had the potential to be a promising adsorbent for fluoroquinolone antibiotics removal with favorable adsorption capacity, environmental security and easy regeneration performance.

Novel insights into the mechanism of periodate activation by heterogeneous ultrasonic-enhanced sludge biochar: Relevance for efficient degradation of levofloxacin.

In this study, a novel heterogeneous ultrasonic (US)-enhanced sludge biochar (SBC) activated periodate (PI) system was established and explored for the rapid removal of levofloxacin in the aqueous environment. This study focused on the mechanisms of US-enhanced SBC co-activation of PI for levofloxacin degradation. The results indicated that US and SBC exhibited a remarkable synergistic reinforcing activation effect on PI compared to single PI activation systems. The SBC/US/PI system achieved approximately 95% of levofloxacin removal, 51.5% of TOC removal, and 22% of dechlorination rate within 60 min with virtually no heavy metals released into the water matrix. In addition, the acute ecotoxicity of the solutions treated with the SBC/US/PI system was substantially reduced. The presence of IO3•, •OH, 1O2 and O2•- were identified in the SBC/US/PI system using quenching experiments and EPR technology while •OH and 1O2 were the predominant reactive species. Mechanistic studies have suggested that the cavitation effect of ultrasonic improved the dispersion and mass transfer efficiency of SBC and accelerated the desorption process of SBC. Possible pathways of levofloxacin degradation were proposed. This study provides a novel and promising strategy for the efficient removal of emerging contaminants such as antibiotics from the water matrix.

An efficient, green and sustainable potassium hydroxide activated magnetic corn cob biochar for imidacloprid removal.

The extensive use of imidacloprid (IMI) has led to its being frequently detected in natural water, also caused the potential damage to the ecosystem. Development of efficient, green and sustainable technique is demanded to eliminate this problem. A novel biochar (KMCBC) derived from agriculture waste of corn cob was first time co-modified by potassium hydroxide (KOH), ferric chloride (FeCl3) and zinc chloride (ZnCl2), which showed the greater adsorption amount (410 mg g-1 at 298 K) for imidacloprid (IMI). Pseudo-second-order kinetic and Langmuir isotherm models fitted well with the experimental data, together with the physicochemical characterization analysis, demonstrating that the adsorption process of IMI by KMCBC might be mainly controlled by micropore filling, π-π electron donor-acceptor and functional groups interactions (H-bonding and complexation). Additionally, the thermodynamics parameters suggested that IMI adsorption in this study was a spontaneous, endothermic and randomly increasing process. Besides, KMCBC owned the easy separation performance and promising environmental safety, also exhibited a high selective adsorption capacity regardless of solution pH (its optimum adsorption performance for IMI was obtained at pH = 5), inorganic ions strength and humic acid (HA) concentrations. The regenerated KMCBC (synergistic ultrasound/ethanol) could sustainably and efficiently adsorb IMI in the reuse cycles. Therefore, this study provided an efficient, green and sustainable adsorbent of KMCBC for IMI removal.