Dry deposition fluxes and inhalation risks of toxic elements in total suspended particles in the Bohai Rim region: Long-term trends and potential sources.

Long-term changes in dry deposition fluxes (DDF) and health risks for toxic elements (TE) in total suspended particles (TSP) in the Bohai Rim region are important for assessing control effects of pollution sources. Thus, we investigated the trends in DDF and concentrations for TSP and TE and health risks of TE in eight cities in the region from 2011-2020. TSP concentration and DDF showed general downward trends. Compared to the before Clear Air Action Plan (BCAAP, 2011-2012) period, concentration and DDF of TE over the Clear Air Action Plan (CAAP, 2013-2017) period substantially decreased, with the highest decrease rates in Zn, Cd, and Cr. During the study period, non-carcinogenic (HI) and total carcinogenic (TCR) risks for children and adults were 0.09 and 0.04, and 1.54 × 10-5 and 2.65 × 10-5, respectively, with Cr6+ and As being dominant contributors. Compared to the BCAAP period, HI and TCR over the CAAP period decreased by 36.8 % and 32.4 %, respectively. However, their risks increased over the Blue Sky Protection Campaign (BSPC, 2018-2020) period. Potential source contribution function suggested substantial changes in potential risk areas over different control periods, with the BSPC primarily being on land and the Yellow Sea.

Optimizing Paclitaxel Oral Absorption and Bioavailability: TPGS Co-Coating via Supercritical Anti-Solvent Fluidized Bed Technology.

Supercritical anti-solvent fluidized bed (SAS-FB) coating technology has the advantages of reducing particle size, preventing high surface energy particle aggregation, improving the dissolution performance and bioavailability of insoluble drugs. The poor solubility of Biopharmaceutics Classification System (BCS) class IV drugs poses challenges in achieving optimal bioavailability. Numerous anti-cancer drugs including paclitaxel (PTX) belong to the BCS class IV, hindering their therapeutic efficacy. To address this concern, our study explored SAS-FB technology to coat PTX with D-α-tocopherol polyethylene glycol 1000 succinate (TPGS) onto lactose. Under our optimized conditions, we achieved a PTX coating efficiency of 96.8%. Further characterization confirmed the crystalline state of PTX in the lactose surface coating by scanning electron microscopy and X-ray powder diffraction. Dissolution studies indicated that SAS-FB processed samples release over 95% of the drug within 1 min. Moreover, cell transmembrane transport assays demonstrated that SAS-FB processed PTX samples co-coated with TPGS had an enhanced PTX internalization into cells and a higher permeability coefficient compared to those without TPGS. Finally, compared to unprocessed PTX, SAS-FB (TPGS) and SAS-FB processed samples showed a 2.66- and 1.49-fold increase in oral bioavailability in vivo, respectively. Our study highlights the efficacy of SAS-FB co-coating for PTX and TPGS as a promising strategy to overcome bioavailability challenges inherent in BCS class IV drugs. Our approach holds broader implications for enhancing the performance of similarly classified medications.

Intramolecular generation of endogenous Cu(III) for selectively self-catalytic degradation of Cu(II)-EDTA from wastewater by UV/peroxymonosulfate.

HO•/SO4•--based advanced oxidation processes for the decomplexation of heavy metal-organic complexes usually encounter poor efficiency in real scenarios. Herein, we reported an interesting self-catalyzed degradation of Cu(II)-EDTA with high selectivity in UV/peroxymonosulfate (PMS). Chemical probing experiments and competitive kinetic analysis quantitatively revealed the crucial role of in situ formed Cu(III). The Cu(III) species not only oxidized Cu(II)-EDTA rapidly at ∼3 × 107 M-1 s-1, but also exhibited 2-3 orders of magnitude higher steady-state concentration than HO•/SO4•-, leading to highly efficient and selective degradation of Cu(II)-EDTA even in complex matrices. The ternary Cu(II)-OOSO3- complexes derived from Cu(II)-EDTA decomposition could generate Cu(III) in situ via the Cu(II)-Cu(I)-Cu(III)-Cu(II) cycle involving intramolecular electron transfer. This method was also applicable to various Cu(II) complexes in real electroplating wastewater, demonstrating higher energy efficiency than commonly studied UV-based AOPs. This study provids a proof of concept for efficient decomplexation through activating complexed heavy metals into endogenous reactive species.

Multiple roles of UV/KMnO4 in cyanobacteria containing water treatment: Cell inactivation & removal, and microcystin degradation.

Cyanobacterial blooms present great challenges to drinking water treatment and human health. The novel combination of potassium permanganate (KMnO4) and ultraviolet (UV) radiation is engaged as a promising advanced oxidation process in water purification. This study investigated the treatment of a typical cyanobacteria, Microcystis aeruginosa by UV/KMnO4. Cell inactivation was significantly improved by UV/KMnO4 treatment, compared to UV alone or KMnO4 alone, and cells were completely inactivated within 35 min by UV/KMnO4 in natural water. Moreover, effective degradation of associated microcystins was simultaneously achieved at UV fluence rate of 0.88 mW cm-2 and KMnO4 dosages of 3-5 mg L-1. The significant synergistic effect is possibly attributable to the highly oxidative species produced during UV photolysis of KMnO4. In addition, the cell removal efficiency via self-settling reached 87.9 % after UV/KMnO4 treatment, without additional coagulants. The fast in situ generated manganese dioxide was responsible for the enhancement of M. aeruginosa cell removal. This study firstly reports multiple roles of UV/KMnO4 process in cyanobacterial cell inactivation and removal, as well as simultaneous microcystin degradation under practical conditions.

MOF-derived CeO2/Co3O4-Fe2O3@CC nanocomposites as highly sensitive electrochemical sensor for bisphenol A detection.

A novel CeO2/Co3O4-Fe2O3@CC electrode derived from CeCo-MOFs was developed for detecting the endocrine disruptor bisphenol A (BPA). Firstly, bimetallic CeCo-MOFs were prepared by hydrothermal method, and obtained material was calcined to form metal oxides after doping Fe element. The results suggested that hydrophilic carbon cloth (CC) modified with CeO2/Co3O4-Fe2O3 had good conductivity and high electrocatalytic activity. By the analyses of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), the introduction of Fe increased the current response and conductivity of the sensor, greatly increasing the effective active area of the electrode. Significantly, electrochemical test proves that the prepared CeO2/Co3O4-Fe2O3@CC had excellent electrochemical response to BPA with a low detection limit of 8.7 nM, an excellent sensitivity of 20.489 µA/µM·cm2, a linear range of 0.5-30 µM, and strong selectivity. In addition, the CeO2/Co3O4-Fe2O3@CC sensor had a high recovery rate for the detection of BPA in real tap water, lake water, soil eluent, seawater, and PET bottle samples, which showed its potential in practical applications. To sum up, the CeO2/Co3O4-Fe2O3@CC sensor prepared in this work had excellent sensing performance, good stability and selectivity for BPA, which can be well used for the detection of BPA.

Generation mechanism of singlet oxygen from the interaction of peroxymonosulfate and chloride in aqueous systems.

Peroxymonosulfate (PMS, HSO5-) is a widely-used disinfectant and oxidant in environmental remediation. It was deemed that PMS reacted with chloride (Cl-) to form free chlorine during water purification. Here, we demonstrated that singlet oxygen (1O2) was efficiently generated from PMS and Cl- interaction. Mechanism of 1O2 formation was uniquely verified by the reaction of HSO5- and chlorine molecule (Cl2) and the oxygen atoms in 1O2 deriving from the peroxide group of HSO5- were revealed. Density functional theory calculations determined that the reaction of HSO5- and Cl2 was thermodynamically favorable and exergonic at 37.8 kcal/mol. Quite intriguingly, 1O2 was generated at a higher yield (1.5 × 105 M - 1 s - 1) than in the well-known reaction of H2O2 with Cl2 (35 M - 1 s - 1). Besides chlorine, 1O2 formed in PMS-Cl- interaction dominated the degradation of micropollutants, also it substantially enhanced the damage of deoxynucleoside in DNA, which were beneficial to micropollutant oxidation and pathogen disinfection. The contribution of 1O2 for carbamazepine degradation was enhanced at higher Cl- level and lower pH, and reached 96.3% at pH 4.1 and 5 min. Natural organic matter (NOM) was a sink for chlorine, thereby impeding 1O2 formation to retard carbamazepine degradation. 1O2 also played important roles (48.3 - 63.5%) on the abatement of deoxyguanosine and deoxythymidine at pH 4.1 and 10 min in PMS/Cl-. On the other hand, this discovery also alerted the harm of 1O2 for human health as it can be formed during the interaction of residual PMS in drinking water/swimming pools and the high-level Cl- in human bodies.

Efficient removal of Cr(VI) at alkaline pHs by sulfite/iodide/UV: Mechanism and modeling.

Efficient removal of toxic hexavalent chromium (Cr(VI)) under alkaline conditions is still a challenge due to the relatively low reactivity of CrO42-. This study proposed a new sulfite/iodide/UV process to remove Cr(VI). The removal of Cr(VI) followed pseudo-zero-order kinetics at alkaline pHs, and was enhanced by sulfite and iodide with synergy. Compared with sulfite/UV, iodide in sulfite/iodide/UV showed about 40 times higher concentration-normalized enhancement for Cr(VI) removal, and reduced the requirement of sulfite ([S(IV)]0/[Cr(VI)]0 of about 2.1:1) by more than 90%. The Cr(VI) removal was accelerated by decreasing pH and by increasing temperature, and was slightly influenced by dissolved oxygen, carbonate, and humic acid. The process was still effective in real surface water and industrial wastewater. Mechanism and pathways of Cr(VI) removal were revealed by quenching experiments, competition kinetic analysis, product identification and quantification, and mass and electron balance. Both eaq- and SO3•- were responsible for Cr(VI) removal, making contributions of about 75% and 25%, respectively. When eaq- mainly reacted with Cr(VI), SO3•- participated in reduction of Cr(V) and Cr(IV) intermediates, with Cr(III), S2O62-, and SO42- as the final products. A model was developed to predict removal kinetics of Cr(VI), and well interpreted the roles of S(IV) and iodide in the process. This study sheds light on mechanism of Cr(VI) removal at alkaline pHs by kinetic modeling, and thus advances the applicability of this promising process for water decontamination.

A newly-designed free-standing NiCo2O4 nanosheet array as effective mediator to activate peroxymonosulfate for rapid degradation of emerging organic pollutant with high concentration.

Nowadays effective treatment of high concentration organic wastewater is still a formidable task facing human beings. Herein, for the first time, a well-defined ZIF-67-derived NiCo2O4 nanosheet array was successfully prepared by a feasible method. In comparison with ordinary NiCo2O4 nanosphere, the formation of nanosheet structure could offer more opportunities to exposure internal active sites of NiCo2O4, thereby resulting in smaller interface resistance and higher charge transfer efficiency. As expected, ZIF-67-derived NiCo2O4 nanosheet array displayed great performance in peroxymonosulfate (PMS) activation. More importantly, recyclable redox couples of Co3+/Co2+ and Ni3+/Ni2+ endowed the stable catalytic activity of NiCo2O4 nanosheet. Interestingly, developed NiCo2O4-1/PMS oxidation system could achieve the effective degradation of antibiotics with high concentration in a short time. Both radical and nonradical pathways were involved into PMS activation, wherein SO4-, OH, O2- and 1O2 were major reactive oxygen species. The formation paths of reactive oxygen species and effects of inorganic anions were also investigated. Electrochemical analyses revealed that NiCo2O4-1 with nanosheet structure mediated the electron transfer between PMS and tetracycline (TC), which played a vital role in TC degradation. Furthermore, developed NiCo2O4-1/PMS oxidation system displayed great removal ability towards TC in actual water samples, and degradation products were low toxicity or no toxicity. In short, current work not only developed an effective oxidation system for completing the rapid degradation of antibiotic with high concentration, but also shared some novel insights into the activation mechanism of SR-AOPs.

Fabrication of 3D self-supported MoS2-Co-P/nickel foam electrode for adsorption-electrochemical removal of Cr(â ¥).

Electrochemistry is considered to be one of the most efficient and environment-friendly methods for removing highly toxic Cr (Ⅵ). In this study, a 3D self-supported MoS2-Co-P/nickel foam (NF) electrode was prepared via a calcination-hydrothermal process to remove the Cr (Ⅵ) in aqueous medium. Scanning electron microscope (SEM) analysis indicated that the pine-needle-like Co2P nanoneedle and flower-like MoS2 nanosheets were successfully loaded on the three-dimensional (3D) framework of NF, which provided abundant active sites. The electrode modified by Co, P and MoS2 exhibited high removal efficiency of Cr (Ⅵ) (96.9%) at pH 3.0, current of 0.128 mA and voltage of 2.5 V. Co, P and MoS2 have the synergistic promotion on the catalytic performance of electrodes, and the reduction efficiency of Cr (Ⅵ) was greatly improved by 127.5 times relative to pure NF. The enhanced removal of Cr (Ⅵ) was related to the coupling effect of adsorption and electrocatalytic reduction. The mechanism study indicated that electron (e-) is the active species of Cr (Ⅵ) reduction. The Cr (Ⅵ) removal rate was maintained at 90 ± 1% after five successive cycle experiments, demonstrating good stability and potential industrial applications of MoS2-Co-P/NF.

Thiourea Dioxide Coupled with Trace Cu(II): An Effective Process for the Reductive Degradation of Diatrizoate.

Diatrizoate, a refractory ionic iodinated X-ray contrast media (ICM) compound, cannot be efficiently degraded in a complex wastewater matrix even by advanced oxidation processes. We report in this research that a homogeneous process, thiourea dioxide (TDO) coupled with trace Cu(II) (several micromoles, ubiquitous in some wastewater), is effective for reductive deiodination and degradation of diatrizoate at neutral pH values. Specifically, the molar ratio of iodide released to TDO consumed reached 2 under ideal experimental conditions. TDO eventually decomposed into urea and sulfite/sulfate. Based on the results of diatrizoate degradation, TDO decomposition, and Cu(I) generation and consumption during the TDO-Cu(II) reaction, we confirmed that Cu(I) is responsible for diatrizoate degradation. However, free Cu(I) alone did not work. It was proposed that Cu(I) complexes are actual reactive species toward diatrizoate. Inorganic anions and effluent organic matter negatively influence diatrizoate degradation, but by increasing the TDO dosage, as well as extending the reaction time, its degradation efficiency can still be guaranteed for real hospital wastewater. This reduction reaction could be potentially useful for in situ deiodination and degradation of diatrizoate in hospital wastewater before discharge into municipal sewage networks.

Insights into the effects of bromide at fresh water levels on the radical chemistry in the UV/peroxydisulfate process.

Bromide (Br-) is a typical scavenger to sulfate radical (SO4•-) and hydroxyl radical (HO•), which simultaneously forms secondary reactive bromine species (RBS) such as Br• and Br2•-. This study investigated the effects of Br- at fresh water levels (~µM) on the radical chemistry in the UV/peroxydisulfate (UV/PDS) process by combining the degradation kinetics of probe compounds (nitrobenzene, metronidazole, and benzoate) with kinetic model. Br- at 1 - 50 µM promoted the conversion from SO4•- to HO• and RBS in the UV/PDS process. At pH 7, the concentration of SO4•- monotonically decreased by 31.5 - 94.8% at 1 - 50 µM Br-, while that of HO• showed an increasing and then decreasing pattern, with a maximum increase by 171.7% at 5 µM Br-. The concentrations of Br• and Br2•- (10-12 - 10-10 M) were 2 - 3 orders of magnitude higher than SO4•- and HO•. Alkaline condition promoted the conversion from SO4•- to HO•, and drove the transformation from RBS to HO•, resulting in much lower concentrations of RBS at pH 10. Br- at 1 µM and 5 µM decreased the pseudo-first-order reaction rates (k's) of 15 pharmaceuticals and personal care products (PPCPs) by 15.2 - 73.9%, but increased k's of naproxen and ibuprofen by 13.7 - 57.3% at pH 7. The co-existence of 10 - 1000 µM Cl- with 5 µM Br- further promoted the conversion from SO4•- to HO• compared to Br- alone. Bicarbonate consumed SO4•- and HO• but slightly affected RBS, while natural organic matter (NOM) exerted scavenging effects on HO• and RBS more significantly than SO4•-. This study demonstrated that Br- at fresh water levels significantly altered the radical chemistry of the UV/PDS process, especially for promoting the formation of HO•.

The impact of automatic video auditing with real-time feedback on the quality and quantity of handwash events in a hospital setting.

BACKGROUND: Poor quality handwashing contributes to the spread of nosocomial infections. We investigate the impact of automatic video auditing (AVA) with feedback on the quality and quantity of handwashing in a hospital setting. METHODS: AVA systems were mounted over all handwash sinks in a surgical unit. Phase 1 established baseline handwashing quality and quantity. Phase 2 examined the impact of real-time performance feedback, and phase 3 examined the incremental impact of weekly team performance reports. Phase 4 remeasured the baseline without feedback. RESULTS: A total of 3,606 handwash events were audited. During phase 2 and 3, compliance with the World Health Organization technique improved from 15.7%-46% (P < .0001), and the average number of handwash events per patient per day increased from 0.91-2.25 (P < .0001). Performance returned to baseline in phase 4. CONCLUSIONS: AVA with real-time feedback significantly improved the quality and quantity of handwashing. The combination of AVA with electronic monitoring will allow simultaneous auditing of hand hygiene quantity and quality. The impact of cognitive offloading onto the technology may have contributed to the return to baseline at the end of the study, and suggests further research is required in this area.

A pilot study of blood supply of the coracoid process and the coracoid bone graft after Latarjet osteotomy.

Latarjet osteotomy is still one of the most reliable and commonly used surgeries in treating recurrent anterior shoulder dislocation. The coracoid process (CP) is the main structure of this surgery. However, the blood supply of CP is not fully understood, and the extent of destruction of blood supply of coracoid bone graft after Latarjet osteotomy procedure is still controversial. Five embalmed cadaveric upper limbs specimens were employed for macro observation of the blood supply of CP. The conjoint tendon (CT) and CP interface were dissected for histology. Sixteen fresh frozen shoulder specimens were used for perfusion and micro CT scanning. Eight specimens were used to present the whole vessel structure of CP. The other eight underwent Latarjet osteotomy procedure. The coracoid bone grafts in both groups were scanned to clarify the remnant blood supply. It was found that the CP was nourished by supra-scapular artery (SSA), thoracic-acromial artery and branch from second portion of the axillary artery (AA). After Latarjet osteotomy procedure, no artery from CT was detected to penetrate the CP at its attachment. Only in one specimen the blood vessel that originated from the CT penetrated the bone graft at the inferior side. Therefore, most of the blood supply was destroyed although there is a subtle possibility that the vessels derived from the CT nourished the inferior side of the CP. In a nutshell, CP is a structure with rich blood supply. The traditional Latarjet osteotomy procedure would inevitably cut off the blood supply of the coracoid bone graft.

Degradation of metronidazole by UV/chlorine treatment: Efficiency, mechanism, pathways and DBPs formation.

Metronidazole (MET) is a widely used antibiotic but is recalcitrant in aquatic environment. This study investigated elimination of MET by UV/chlorine process systematically. The degradation of MET in the process well fitted pseudo first-order kinetics. Decreasing pH from 9 to 5 raised the rate constant from 0.0199 min-1 to 0.1485 min-1, possibly ascribed to change in species distribution and apparent quantum yields of radicals. Scavenging experiments indicated that both HO and Cl contributed to the degradation of MET, and that HO was the dominant species in the pH range studied. The second-order rate constant between Cl and MET was determined to be (5.64 ±â€¯0.1) × 109 M-1 s-1. Three products were identified by UPLC-Q-TOF MS and degradation pathway was thus proposed. Significant amounts of chlorinated disinfection by-products (DBPs) were produced and 1,1,1-TCP was the dominant (83.6%-92.3%) in the UV/chlorine process. The kinetic model developed fitted well with experimental results, and was used to examine the effects of typical water parameters, such as chorine dosage, pH, inorganic anions, NOM and real water matrix. Furthermore, removal efficiency of MET by the UV/chlorine process were assessed in terms of electrical energy per order (EE/O). The efficiency was about 0.43 kWh m-3 order-1, 0.54 kWh m-3 order-1, 0.57 kWh m-3 order-1, respectively, for the removal of MET in ultrapure water (UPW) and two types of real water samples, indicating that UV/chorine was a practical method for authentic drinking water treatment practices.

Overlooked Role of Peroxides as Free Radical Precursors in Advanced Oxidation Processes.

Research efforts on advanced oxidation processes (AOPs) have long been focused on the fundamental chemistry of activation processes and free radical reactions. Little attention has been paid to the chemistry of the precursor oxidants. Herein, we found that the precursor oxidants could lead to quite different outcomes. A counterintuitive result was observed in the photoreduction of bromate/iodate: the combination of H2O2 and UV enhanced the reduction of bromate/iodate, whereas the addition of persulfate to the UV system led to an inhibitory effect. Thermodynamic and kinetic evidence suggests that the reduction of bromate in UV/H2O2 was attributable to the direct reaction between HOBr and H2O2. Both experimental determination and kinetic simulation demonstrate that the reaction between HOBr and H2O2 dominated over the •OH-mediated reactions. These results suggest that H2O2 possesses some particular redox properties that distinguish it from other peroxides. The prototypical UV/H2O2 process is not always an AOP: it can also be an enhanced reduction process for chemicals with intermediates that are reducible by H2O2. Considering the increasing interest in persulfate-based AOPs, the results of this study identify some novel advantages of the classical H2O2-based AOPs.

Autocatalytic Decomplexation of Cu(II)-EDTA and Simultaneous Removal of Aqueous Cu(II) by UV/Chlorine.

Traditional processes usually cannot enable efficient water decontamination from toxic heavy metals complexed with organic ligands. Herein, we first reported the removal of Cu(II)-EDTA by a UV/chlorine process, where the Cu(II)-EDTA degradation obeyed autocatalytic two-stage kinetics, and Cu(II) was simultaneously removed as CuO precipitate. The scavenging experiments and EPR analysis indicated that Cl• accounted for the Cu(II)-EDTA degradation at diffusion-controlled rate (∼1010 M-1 s-1). Mechanism study with mass spectrometry evidence of 11 key intermediates revealed that the Cu(II)-EDTA degradation by UV/chlorine was an autocatalytic successive decarboxylation process mediated by the Cu(II)/Cu(I) redox cycle. Under UV irradiation, Cu(I) was generated during the photolysis of the Cl•-attacked complexed Cu(II) via ligand-to-metal charge transfer (LMCT). Both free and organic ligand-complexed Cu(I) could form binary/ternary complexes with ClO-, which were oxidized back to Cu(II) via metal-to-ligand charge transfer (MLCT) with simultaneous production of Cl•, resulting in the autocatalytic effect on Cu(II)-EDTA removal. Effects of chlorine dosage and pH were examined, and the technological practicability was validated with authentic electroplating wastewater and other Cu(II)-organic complexes. This study shed light on a new mechanism of decomplexation by Cl• and broadened the applicability of the promising UV/chlorine process in water treatment.

Comparison of the UV/chlorine and UV/H2O2 processes in the degradation of PPCPs in simulated drinking water and wastewater: Kinetics, radical mechanism and energy requirements.

The degradation of pharmaceuticals and personal care products (PPCPs) by the UV/H2O2 and UV/chlorine processes was compared at practical concentrations in simulated drinking water and wastewater. In pure water, the UV/chlorine process performed better than the UV/H2O2 process for the degradation of 16 PPCPs among the investigated 28 PPCPs under neutral conditions. Interestingly, the UV/chlorine approach was superior to the UV/H2O2 approach for the removal of all PPCPs in simulated drinking water and wastewater at the same molar oxidant dosage. The radical sink by oxidants and/or H2O was 2-3 orders of magnitude higher in UV/chlorine than UV/H2O2 in pure water. Thus, the UV/chlorine process was less affected by the water and wastewater matrices than UV/H2O2. In UV/chlorine, the concentration of ClO• was calculated to be ∼3 orders of magnitude greater than that of HO• in pure water, and the reactivities of ClO• with some PPCPs were as high as > 108 M-1 s-1. ClO• was mainly scavenged by the effluent organic matter (EfOM) with a rate constant of 1.8 × 104 (mg L-1)-1 s-1 in wastewater. Meanwhile, secondary radicals such as Br•, Br2•-, ClBr•- and CO3•- further contributed to PPCP degradation by the UV/chlorine process in wastewater, whose concentrations were at least 2 orders of magnitude higher than that in UV/H2O2. Compared with the UV/H2O2 process, the UV/chlorine process saved 3.5-93.5% and 19.1%-98.1% electrical energy per order (EE/O) for PPCP degradation in simulated drinking water and wastewater, respectively.

Kinetics and mechanisms of the degradation of PPCPs by zero-valent iron (Fe°) activated peroxydisulfate (PDS) system in groundwater.

The abatement of pharmaceuticals and personal care products (PPCPs), including carbamazepine (CBZ), acetaminophen (ACP) and sulfamethoxazole (SMX), by zero-valent iron (Fe°) activated peroxydisulfate (PDS) system (Fe°/PDS) in pure water and groundwater was investigated. The removal rates of CBZ, ACP and SMX were 85.4%, 100% and 73.1%, respectively, within 10 min by Fe°/PDS in pure water. SO4•-, •OH and O2•- were identified in the Fe°/PDS system, and O2•- was indicated to play an important role in the ACP degradation. The degradation of PPCPs increased with increasing dosages of Fe° and PDS or with decreasing pH and initial PPCP concentrations. Interestingly, the degradation of PPCPs by Fe°/PDS was significantly enhanced in groundwater compared with that in pure water, which was partially attributed to SO42- and Cl-. The first-order constants of CBZ, ACP and SMX increased from 0.021, 0.242 and 0.013 min-1 to 0.239, 2.536 and 0.259 min-1, and to 0.172, 1.516 and 0.197 min-1, respectively, with increasing the concentrations of SO42- and Cl- to 100 mg/L and 10 mg/L, respectively. This study firstly reports the unexpected enhancement of groundwater matrix on the degradation of micropollutants by Fe°/PDS, demonstrating that Fe°/PDS can be an efficient technology for groundwater remediation.