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Objective. The concentration of exhaled NO and CO is considered as a candidate marker of respiratory inflammatory disease. This report discusses the exhaled NO and CO in the auxiliary diagnosis and evaluation of allergic rhinitis (AR). Methods. 60 AR patients from October 2017 to March 2019, compared with 30 healthy controls. The severity of AR disease was distinguished by symptom score. Both groups were tested for exhaled nitric oxide through the nose or mouth and exhale carbon monoxide through the mouth. AR patients received glucocorticoid nasal spray for 1 month and were tested again for nNO, eNO, eCO, and symptom score. Results. Before treatment, all the nNO, eNO, and eCO of the AR group were higher than the control group. There were differences in the severe and moderate subgroup: severe > moderate > mild. eCO was not significantly different between the mild and control groups. The nNO, eNO, and eCO levels were positively correlated with symptom score. After treatment, nNO decreased significantly in the three subgroups; eNO and eCO in the severe AR group decreased significantly. Drawing the ROC curve, the area under curve (AUC) of nNO is 0.978. The AUC of eNO and eCO was 0.786 and 0.577, respectively. Conclusion. The nNO, eNO, and eCO in the AR group are higher than healthy people, which positively correlated with the severity of AR symptoms. The detection of nNO, eNO, and eCO can monitor the changes of AR. The detection of nNO level as an indicator of AR auxiliary diagnosis has high accuracy. [ABSTRACT FROM AUTHOR]

Graft modified flocculants have recently received increasing attention in the field of water treatment as they have the combinative advantages of synthetic and natural polymeric flocculants. In this work, surface-active monomer benzyl(methacryloyloxyethyl)dimethylammonium chloride (BMDAC) was selected to graft on dextran (DX) with high molecular weight (10.3 × 10 6  g/mol) produced through enzyme-catalyzed process in order to remove dissolved dyes from wastewater. The flocculant (DAB) was fabricated by ultrasound initiated polymerization technique, and the structure characterization of FTIR, 1 H/ 12 C NMR, XRD and XPS spectrum confirmed the successful grafting. Then the Congo red (CR) removal efficiency by DAB was optimized based on the flocculation conditions, including wastewater initial pH, flocculant dosage and initial dye concentration. The effect of suspended solids on the removal of dyes was evaluated in kaolin-CR simulated wastewater. The results indicated that the optimal removal efficiency of CR was 68.1% and 88.2% in single CR and kaolin-CR flocculation system, respectively. The improvement of removal efficiency was attributed to the fact that partial CR molecules were adsorbed onto kaolin particles before flocculation, and were synergistically flocculated accompanied by kaolin particles. Finally, the flocculation mechanism was discussed by a detailed investigation of the zeta potentials, FTIR and XPS spectra of flocs, which can provide important reference for optimizing the flocculation conditions and designing novel high-performance flocculants. [ABSTRACT FROM AUTHOR]

Weak interaction between flocculants and oil is a main bottleneck in the treatment of oil-containing wastewater. To solve this problem, a novel flocculant PAB with cationic micro-block structure and hydrophobic groups of benzene rings was synthesized by ultrasound initiated polymerization technique and applied to remove turbidity and oil from water. To avoid unnecessary addition of reagents in traditional template and micellar copolymerization, surface-active monomer benzyl(methacryloyloxyethyl)dimethylammonium chloride (BMDAC) with self-assembly ability in aqueous solution was employed to synthesize flocculants. The critical association concentration of BMDAC measured by conductivity and surface tension methods was 0.014 mol·L −1 . The results of reactivity ratio, statistical analysis of sequence-length distribution and 1 H NMR provided evidence for the synthesis of copolymer with cationic micro-block. In addition, the apparent viscosity measurement indicated that PAB had an obvious hydrophobic association property. Finally, flocculation tests demonstrated that flocculation performance was greatly improved by adding PAB and the removal rate of oil and turbidity both reached the maximum (87.5% and 92%) at dosage of 40 mg·L −1 and pH of 7.0. Flocculation mechanism investigation demonstrated that the cooperation of charge neutralization, adsorption bridging, and hydrophobic association effect played an important role. The formed flocs by PAB was large, compact, difficult to break, and easy to regrow because of the enhanced interaction between flocculants and oil. In summary, this study can provide important reference in the design of organic flocculants in oily wastewater treatment applications. [ABSTRACT FROM AUTHOR]

Volumes of oily wastewater are inevitably generated by every walk of life. The removal of oil particles from oil-contaminated wastewater which is characterized as huge amounts, intricate composition, and great threats to human health and the ecological environment is a research hotspot in water treatment fields. Due to high treatment costs and undesirable treatment efficiencies, oily wastewater treatment remains a topical and urgent issue. At present, coagulation/flocculation as an indispensable oily wastewater treatment technology receives much attention because it is very well established, economical, practical and relatively efficient. The influencing factors of oil wastewater treatment by coagulation/flocculation have also been summarized in-depth, like dosage, pH, etc. In consideration of its complex composition and treatment difficulty, this paper will also compare the treatment effects of different coagulants/flocculants used alone and combined effects in oily wastewater treatment: inorganic coagulants, organic synthetic polymeric flocculants, natural flocculants and modified polymeric flocculants. Additionally, in this review, the mechanisms of removing oily substance by coagulation/flocculation are emphasized. Given strict emission standards and the refractory nature of oily wastewater, the combination process with coagulation/flocculation, such as electrocoagulation, coagulation-membrane filtration hybrid process, and coagulation/flocculation-flotation can present better application potential and are discussed in this review. To provide a proper choice in practical application, the operating cost of coagulation and several conventional technologies are also compared. Finally, the existing challenges in the treatment of oily wastewater by coagulation are analyzed, and the feasible research direction is proposed. Unlabelled Image • Few articles focus on the technology of coagulation/flocculation in oily wastewater. • The mechanisms, challenges and research direction of oily wastewater treatment by coagulation/flocculation are discussed. • Coagulation/flocculation presents an excellent removal efficiency on oily wastewater. • Combined technologies for oil removal can meet strict effluent guidelines. [ABSTRACT FROM AUTHOR]

It remains a challenge to remove anionic dyes under alkaline conditions. In this study, we studied the pH independent adsorption of anionic dyes on a surface-active cationic monomer, benzyl(methacryloyloxyethyl)dimethylammonium chloride (BMDAC), which was used to decorate a self-floating adsorbent, BDSA. To compare the pH adaptability, a traditional cationic monomer, methacrylatoethyl trimethyl ammonium chloride (MTAC), which is similar to BMDAC in terms of its structure but does not contain aromatic groups, was used instead of BMDAC to prepare another adsorbent, MDSA. Through comparison of characterization and adsorption experiments, we found that BDSA could maintain a high dye-removal efficiency under different pH conditions. The AG25 removal rate was above 90% in the pH range of 2–10. In addition, BDSA showed outstanding recovery and reutilization performance; its adsorption capacity remained above 80% after five cycles of use. The π-π stacking between the benzyl group in BDSA and the aromatic ring in the dye molecule was found to enhance the adsorption interaction, which was confirmed by theoretical calculations. With its excellent adsorption capacity for anionic dyes, high pH adaptability, easy separation ability and good reusability, BDSA is an ideal candidate for dye wastewater treatment. Image 1 • This article contains the preparation and characterization of self-floating adsorbent. • The adsorption performance of MDSA and BDSA was compared by adsorption experiments. • BDSA's high pH adaptability is due to a unique adsorption mechanism. • The mechanism of stable adsorption under a wide range of pH was elucidated by instrumental analysis and theoretical calculation. • This paper evaluates the reutilization performance of the novel adsorbent BDSA. [ABSTRACT FROM AUTHOR]

Objective: To compare the efficacy of gentamicin and steroids in patients with Meniere's disease (MD). Methods: The study protocol was structured in accordance with the Population, Intervention, Comparison and Outcome (PICO) framework. We used "Endnote" (Thomson ResearchSoft; Stanford, Connecticut, the United States) to retrieve database documents. A systematic literature search of Web of Science and PubMed Database through May 2020 was conducted using specific search terms. Inclusion criteria, exclusion criteria, vertigo improvement, and exact hearing changes were defined. Review Manager 5.3 (Cochrane) was used for data analysis. Results: A total of 80 articles were searched from Web of Science and 23 articles were searched from PubMed database. After further reviewing the specific points of the inclusion criteria and exclusion criteria, 9 papers were finally selected. Intratympanic gentamicin (ITG) was superior to intratympanic steroid (ITS) in reducing the number of vertigo attacks (odds ratio (OR) 3.08, 95% confidence intervals (CI) [2.05–3.65]), probability (P) < 0.01). As for hearing improvement, we did the analysis twice. With all the studies included, the odds of hearing improvement (by "x") was 0.31 among patients receiving gentamicin compared to those treated by steroids (OR 0.31, 95% CI [0.16–0.61]). But after removing one study with outlying results from the analysis, this effect disappeared. Hearing loss of ITG and ITS was not statistically significant (P = 0.29). Conclusions: ITG is superior to ITS in reducing the number of vertigo attacks in the treatment of MD (P < 0.01); the impact on hearing is more heterogeneous in the studies. Overall, there was no clear difference between ITG and ITS on hearing improvement and on hearing loss. [ABSTRACT FROM AUTHOR]

[Display omitted] • Exploring the defluorination performance by different crystalline MnO 2. • Lanthanum-modified MnO 2 with four crystal forms for defluorination were prepared. • Lanthanum loading significantly enhanced the fluoride ions adsorption. • The quantity of surface hydroxyl groups strongly influenced the defluoridation. • Ion exchange was the main process for fluoride ions adsorption. MnO 2 has a large potential for defluoridation, however, the influences of its crystal forms on the performance and mechanism of defluoridation are unknown. The research systematically investigated the defluoridation performance and mechanism of a total of eight materials with different crystal forms of MnO 2 (α, β, γ, δ) before and after lanthanum modification, separately. It was indicated that the largest Langmuir adsorption of α-MnO 2 and La-γ-MnO 2 for fluoride achieved 5.04 mg/g and 42.39 mg/g, correspondingly. The surface hydroxyl group and lanthanum loading of the material proved to be the major contributors to defluoridation. For the adsorption performance of eight materials on fluoride, pH was a significant influencing factor, with the highest adsorption performance at pH 5 ∼ 6. The eight materials showed consistent selectivity for fluoride adsorption in the existence of different anions, with the order of influence on the removal efficiency: CO 3 2–> NO 3 –> SO 4 2–> Cl–. The studies of FTIR, XPS, and variation of solution pH further illustrated that the adsorption mechanism of the eight materials on fluoride was the ion-exchange interaction and the complexation reaction. In addition, the effect of crystal forms on the adsorption of fluoride ions was further elaborated by DFT analysis. Finally, this study provided an in-depth discussion of the parameters of the dynamic process as well as the nature of the penetration curves by applying the Thomas, Clark, and BDST models. [ABSTRACT FROM AUTHOR]

Currently, the hidden risk of microplastics in the coagulation process has attracted much attention. However, previous studies aimed at improving the removal efficiency of microplastics and ignored the importance of interactions between microplastics and natural organic matter (NOM). This study investigated how polystyrene micro/nano particles impact the release of NOM during the aging of flocs formed by aluminum-based coagulants Al 13 and AlCl 3. The results elucidated that nano-particles with small particle sizes and agglomerative states are more likely to interact with coagulants. After 7 years of floc aging, the DOC content of the nano system decreased by more than 40%, while the micron system did not change significantly. During coagulation, the benzene rings in polystyrene particles form complexes with electrophilic aluminum ions through π-bonding, creating new Al-O bonds. NOM tends to adsorb at micro/nano plastic interfaces due to hydrophobic interactions and conformational entropy. In the aging process, the structure of PS-Al 13 or PS-AlCl 3 flocs and the functional groups on the surface of micro/nano plastics control the absorption and release of organic matter through hydrophobic, van der Waals forces, hydration, and polymer bridging. In the system with the addition of nano plastics, several DBPs such as TCAA, DCAA, TBM, DBCM and nitrosamines were reduced by more than 50%. The reaction order of different morphological structures and surface functional groups of microplastics to Al 13 and AlCl 3 systems is aromatic C-H > C-OH > C-O > NH 2 > aromatic C C > aliphatic C-H and C-O>H-C O> NH 2 >C-OH> aliphatic C-H. The results provided a new sight to explore the effect of micro/nano plastics on the release of NOM during flocs aging. [Display omitted] • Polystyrene plastic particles complex with Al-based coagulants through Al-O bond. • Nano-plastic particles with small sizes are more likely to interact with coagulants. • Micro-nano plastics would affect the reactivity order of functional groups of NOM. • Flocs formed with plastic would adsorb and release NOM in the aging process. • The involvement of Micro-nano plastics may increase the formation of DBPs. [ABSTRACT FROM AUTHOR]

[Display omitted] • The adsorption-degradation of low-concentration diclofenac sodium was achieved. • Adsorption by MPDA-CS promoted degradation rate and realized energy-efficient. • Regeneration of the adsorbent was accomplished simultaneously with the degradation. • Stability and magnetic separation of MPDA-CS facilitated its practical application. Given the widespread occurrence of low-concentration diclofenac sodium (DCFS) in the aquatic milieu, the development of an efficient and economical purification method is essential. Magnetic polydopamine-chitosan modified adsorbent (MPDA-CS) was successfully prepared by coating polydopamine-chitosan onto Fe 3 O 4 nanoparticles in this study. The favorable adsorption performance towards DCFS was well demonstrated by regulating the solution to various pH values and initial concentrations of DCFS. Furthermore, the convincing fitting of pseudo-second-order model and intraparticle diffusion model suggested that the dominance of chemical processes and intraparticle diffusion. The specific adsorption mechanism was presumed to be the interaction between MPDA-CS and DCFS molecules, including electrostatic attraction, hydrogen bonding and aromatic stacking. Through regulating standing time in acidic solution, the integrated homogeneous and heterogeneous photo-Fenton system was employed to degrade adsorbed DCFS through dissolved and surfaced Fe(II)/Fe(III) of MPDA-CS, which achieved the waste utilization of dissolved iron ions with excellent degradation efficiency of 96.38% in 40 min. The adsorption-degradation efficiency of DCFS decreased slightly by 2.2% during the initial three cycles. This work presents an energy-efficient method for removing low-concentration DCFS by drawing on the strengths of adsorption and degradation. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Fe 2 @BC 900℃ -PMS process achieves outstanding degradation rate for CBZ. • Nonradical oxidation acts as dominate role for CBZ degradation. • 1O 2 , electron transfer and Fe(IV) are determined in the Fe 2 @BC 900℃ -PMS process. • The degradation pathways of CBZ are proposed by DFT and LC-MASS. • The toxicity of intermediates is evaluated by ECOSAR. In this study, the synthesis of Fe@BC (biochar) was successfully achieved using a one-step calcination process. The catalyst exhibited notable pore structures, a considerable specific surface area, and surface functional groups. Heterogeneous catalytic experiments further demonstrated that the CBZ degradation was significantly improved in the Fe 2 @BC 900℃ -PMS process, in comparison to alternative catalytic processes. The quenching, ESR analyses, and electrochemical tests (CV, LSV, OCP, and EIS) provided evidence that the CBZ degradation occurred via nonradical pathways involving the participation of 1O 2 , electron transfer, and Fe (IV). Furthermore, the potential mechanisms of PMS activation in the Fe 2 @BC 900℃ -PMS process were systematically elucidated. DFT, LC-MASS tests and ECOSAR suggested that CBZ can be transformed into smaller, less toxic molecules during the treatment. Moreover, the cyclic experiments revealed that the Fe 2 @BC 900℃ -PMS process maintained a consistent oxidation capacity for CBZ even after undergoing ten cycles. Based on the above findings, it can be concluded that the Fe 2 @BC 900℃ -PMS process could effectively degrade organic pollutants in water. [ABSTRACT FROM AUTHOR]

The metal organic frameworks (MOFs) are considered as the effective adsorbents for phosphate removal, while their ultrafine powders limit their practical application. In this study, we fabricate two chitosan (CS) gel beads added with different cerium-based MOFs and coated with PDA for phosphate adsorption. The MOFs doped in beads are CM1 and CM2, in which the Ce(III)/Ce(IV) ratio is 0.36 and 1.46, indicating CM2 is Ce(III) dominated and more suitable for phosphate removal. However, during the process of preparing gel beads, the mixture of chitosan and CM1/CM2 are added drop-by-drop to NaOH solution, leading to the decrease of Ce(III) contents in both of the two beads on account of oxidization. On this basis, in order to improve the phosphate uptake performance and enhance the mechanical strength, polydopamine (PDA) is applied to be coated on the outside. The adsorption capacities of CS-CM1 and CS-CM2 are no more than 20 mg/g higher than that of pure CS, which is also quite equal with the phosphate uptake of CS@PDA (63 mg/g). Due to the reduction of PDA, the content of Ce(III) increasing evidently in the two adsorbents. The maximum phosphate adsorption capacities are 146.8 mg/g and 114.8 mg/g for CS-CM1@PDA and CS-CM2@PDA, respectively. CS-CM2@PDA exhibits the largest treatment volume of ∼1166 BV in the fix-bed column study, much higher than that of CS-CM1@PDA (976 BV). The main reason is that Ce(III) could form binding with phosphate through ligand exchange and precipitation. Those inner-sphere interactions are much stronger than the electrostatic attraction between Ce(IV) and phosphate. Thus, due to this strong affinity, CS-CM2@PDA possessing a higher content of Ce(III) can capture phosphate more easier at low concentration. In summary, owing to reduction of PDA, the Cerium-based MOFs are successfully introduced in CS to realize excellent phosphate removal and exhibit a great prospect in application. [Display omitted] • The chitosan gel beads added with cerium-based MOFs and coated with PDA are fabricated. • The Ce(III) valence state is converted to Ce(IV) during the preparation of gel beads. • PDA coating reduces Ce(IV) and improves mechanical strength. • CS-CM1@PDA and CS-CM2@PDA exhibit high adsorption capacities. • CS-CM2@PDA can treat up to 1166 bed volumes of phosphate in column study. [ABSTRACT FROM AUTHOR]

Wastewater containing highly toxic and non-biodegradable heavy metals and organic dyes poses a serious threat to ecological environment and human health. Adsorption has been regarded as a promising technology to purify this kind of wastewater. Therefore, it is of great importance to develop efficient adsorbents. Herein, a magnetically recyclable adsorbent Fe 3 O 4 -CS/PDAC was facilely fabricated by coating poly(acryloyloxyethyltrimethyl ammonium chloride)-modified chitosan on the surface of Fe 3 O 4 nanoparticles. The morphology, physical-chemical and magnetic properties of as-prepared Fe 3 O 4 -CS/PDAC was fully characterized by various techniques. Its adsorption behaviors towards heavy metal Cr(VI) and organic dye sunset yellow (SY) were systematically investigated. Evidently, Fe 3 O 4 -CS/PDAC exhibited adsorption capacities of 163.93 and 769.23 mg/g for Cr(VI) and SY respectively, much higher than other reported adsorbents. Besides, batch experiment results showed that adsorption capacities decreased slightly with pH increasing from 2.0 to 10.0. Furthermore, Fe 3 O 4 -CS/PDAC could be easily separated and effectively regenerated after adsorption. The superior adsorption performance of Fe 3 O 4 -CS/PDAC could be attributed to the electrostatic interaction and ion exchange between target pollutants and the grafted cationic polymer. Owing to its high adsorption capacity over a wide pH range, rapid separation, easy regeneration and good reusability, Fe 3 O 4 -CS/PDAC has great potential for practical application in water treatment. Unlabelled Image • Novel cationic polymer modified magnetic chitosan beads (Fe 3 O 4 -CS/PDAC) were synthesized. • Fe 3 O 4 -CS/PDAC exhibits a high adsorption capacity towards Cr(VI) and sunset yellow over a wide pH range (2.0-10.0). • Superior adsorption performance is attributed to high density of quaternary ammonium groups on the grafted polymer chains. • Electrostatic interaction and ion exchange are involved in the adsorption process. [ABSTRACT FROM AUTHOR]

As one of the core technologies employed in the field of sludge conditioning, flocculation has the ability to improve the sludge dewatering performance and reduce its volume and amount, which can accordingly result in lower costs in sludge transportation as well as subsequent disposal. Therefore, the development of new and high-efficiency flocculants is a hot topic in this field. The template copolymer (TPAD) of acryloyloxyethyl trimethyl ammonium chloride (DAC) and acrylamide (AM) was successfully synthesized through ultrasonic-template copolymerization using sodium-polyacrylate (NaPAA) as a template. The analysis of FTIR, 1H (13C) NMR, TG/DSC and SEM revealed that TPAD had a conspicuously significant cationic segmental structure. In addition, the results obtained from the analysis on the association constant (K M) and the kinetics of the template reaction indicated that the ultrasonic-template was a free radical initiated polymerization and the polymerization mechanism was I Zip-up (ZIP), and which once again confirmed the formation of the cationic fragment structure. This novel cationic fragment structure in TPAD greatly enhanced the ability of charge neutralization, electric patching, adsorption and bridging, thus improving the active sludge conditioning and dewatering performance (FCMC: 72.9%, SRF: 4.0 × 1012 m·kg−1, d 50 : 228.604 μm, D f : 2.02 at 400 r/min). The floc breakage and regeneration experiments showed that the cationic fragment structure in TPAD could make great contribution to the formation of large and dense floc structures, and these flocs were able to regenerate rapidly after breakage. Finally, it was also known that these large and compact floc structures were beneficial to the creation of more channels and voids, thereby decreasing sludge resistance (SRF) and improving sludge dewatering performance. Unlabelled Image • A cationic polyacrylamide (CPAM) with the cationic segment structure was successfully synthesized through ultrasonic-initiated template copolymerization method. • The copolymerization was demonstrated to follow (Ι) Zip template polymerization mechanism and free radical termination reaction through the analyses of association constant (M K) and polymerization kinetics. • All of the instrumental analysis results indicated the formation of the cationic segments in CPAM. • The cationic segments in CPAM could extremely enhance the ability of electrostatic patching and charge neutralization. • The cationic segment structure was more favorable for the regeneration of the broken flocs to form large and compact flocs which could withstand higher pressures. • The ultrasonic-initiated template copolymer showed an excellent performance in sludge flocculation. [ABSTRACT FROM AUTHOR]

Due to the complexity of contaminants, the effectiveness of traditional flocculants toward water purification is insufficient. To break the limitation, a novel polymer flocculant [chitosan grafted poly (acrylamide-itaconic acid), CS-g-P(AM-IA)] was synthesized via ultraviolet-initiated graft copolymerization reaction. Characterization results revealed that the graft copolymers were successfully synthesized and with rougher surface structure. The solubility of CS-g-P(AM-IA) and chitosan grafted polyacrylamide (CS-g-PAM) were greatly improved and they can dissolve in the wide pH range of 2.0–12.0. CaCl 2 was used as a source of cation bridge to enhance the flocculation of kaolin particles, and its optimum dosage was 150 mg·L −1 . At dosage of 30 mg·L −1 and pH of 5.0, the turbidity removal efficiency of CS-g-P(AM-IA) reached the maximum of 93.8%, whereas those of CS-g-PAM and CS were 96.7% and 76.9%, respectively. The patchwise adsorption of ionic groups embedded in the molecular chain on Ca 2+ -clay complexes took effect to generate flocs with larger particle size. Besides, the decolorization ability of cationic dyes by CS-g-P(AM-IA) was greatly enhanced due to the role of abundant carboxyl groups. In the crystal violet (CV) adsorption experiment, the maximum CV dye removal efficiency for CS-g-P(AM-IA) reached the maximum of 81.6% at dosage of 0.7 mg·mL −1 and pH of 9.0, while those for CS-g-PAM and CS were 51.7% and 36.5%, respectively. [ABSTRACT FROM AUTHOR]

At present, the potential mechanism of manganese oxide (MnO 2) activation of PI and the key active sites of PI activation are still unclear and controversial. To this end, three different crystal forms of MnO 2 were prepared in this study and used to activate PI to degrade pollutants. The results showed that different crystal types of MnO 2 showed different catalytic abilities, and the order was γ-MnO 2 > α-MnO 2 > β-MnO 2. Through quenching experiments, EPR tests, Raman experiments and in situ electrochemical experiments, it has been confirmed that electron transfer-mediated non-free radical process is the main mechanism of pollutant degradation, in which the active substance is the highly active metastable intermediate complex (MnO 2 /PI*). Hydroxyl radical (HO•), superoxide radical (O 2 •−), singlet oxygen (1O 2) and iodine radical (IO 3 •) did not participate in pollutant degradation. The quantitative structure-activity relationship analysis confirmed that the catalytic performance of MnO 2 was highly positively correlated with the surface Mn(IV) content, which indicated that the surface Mn(IV) site was the main active site. Overall, this study will be of great help to the design and application of manganese dioxide activation for periodate degradation of pollutants. [Display omitted] • α-MnO 2 , β-MnO 2 and γ-MnO 2 could all effectively activate PI. • The α-MnO 2 /PI, β-MnO 2 /PI and γ-MnO 2 /PI systems were non-radical processes dominated by electron transfer. • The high activity of metastable intermediate complex (MnO 2 /PI*) was the main factor for organic pollutants removal. • The catalytic activities of MnO 2 were positively correlated with the content of Mn (IV) on the catalyst surface. [ABSTRACT FROM AUTHOR]

A multifunctional carboxylate-rich magnetic chitosan flocculant (Mag@PIA-g-CS) was prepared through surface graft copolymerization on magnetite particles. The effect of monomer molar ratio, initiator and pre-neutralized degree on polymerization rate was determined. Various analytical methods were applied to characterize Mag@PIA-g-CS, exhibiting the successful grafting of polymers, good magnetic feature and core-shell structure. The kinetic process of Ni(II) and malachite green (MG) flocculation by Mag@PIA-g-CS reached equilibrium within <60 min with the optimal uptake rate of 98.3% and 87.4%, and exhibited satisfactory removal effect in wide pH range (4.0–8.0 for Ni(II), 5.0–10.0 for MG). Mag@PIA-g-CS exhibited superior flocculation performance over chitosan magnetic flocculant (Mag@CS). The pH-dependent behavior, rapid responsiveness and sensitivity to ionic strength in batch flocculation tests indicated the distinct effect of ionic groups. Moreover, sweeping action of linear molecular chains facilitated further flocculation. Mag@PIA-g-CS showed high stability in extreme environments, and can be easily regenerated and separated. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mn/Cu co-doped activated carbon particle electrodes were applied in the E-PMS-MCAC process for efficient norfloxacin degradation. • Generation mechanisms of radical and non-radical involved in the E-PMS-MCAC process were explored. • Electron transfer between Mn and Cu improved the activation efficiency of PMS. • Norfloxacin degradation pathways and the toxicity of intermediates in the E-PMS-MCAC process were investigated. In this study, Mn/Cu co-doped activated carbon (MCAC) particle electrodes were applied in the three-dimensional (3D) electrical activation of peroxymonosulfate process (E-PMS-MCAC) for norfloxacin (NOF) degradation. Several comparative experiments demonstrated a significant synergy between catalytic and electric activation of PMS in the E-PMS-MCAC process, which could obtain 90.81 % of NOF removal within 60 min. Quenching experiments and EPR analyses revealed that S O 4 · - , •OH, 1O 2 , and reactive Mn(III) were all involved in the E-PMS-MCAC process, while •OH was dominant reactive species for NOF degradation. The different generation ways of reactive species were also explored. Besides, multiple degradation pathways of NOF were proposed, and the toxicity of intermediates was assessed as well. The characterizations of SEM, XRD, and XPS indicated that the cathodic reduction reaction could facilitate electron transfer to Mn(IV), Mn(III), and Cu(c), triggering the sustainable Mn(I)/Mn(III)/Mn(IV) or Cu(I)/Cu(II) redox cycle. It was noted that the addition of Cl - enhanced the NOF removal, while the presence of HCO 3 - , NO 3 - , and H 2 PO 4 - inhabited it. Finally, the removal efficiencies of other contaminations including p-nitrophenol (PNP), carbamazepine (CBZ), sulfamethoxazole (SMX), and tetracycline hydrochloride (TCH) were also investigated in the E-PMS-MCAC process. All above results suggested that the E-PMS-MCAC process was a high-efficiency and sustainable technology for organic wastewater treatment. [ABSTRACT FROM AUTHOR]

Modified natural polymer flocculants has been the focus of research in environmental engineering field. Natural large molecular compound, chitosan (CTS) with many functional amino and hydroxyl groups can be easily modified to enhance its original functions. This work presents an environmentally friendly chitosan-based cationic polyacrylamide flocculants (CTS-g-PAMA) with enhanced function of sterilization and flocculation. CTS-g-PAMA was synthesized through Ultraviolet (UV)-initiated copolymerization. Structure characterization of FTIR, 1 H NMR, XRD and UV spectrum confirmed the successful grafting of AM and MAPTAC. Scanning electron microscopy (SEM) analysis results showed that CTS-g-PAMA exhibited a porous structure with a prodigious surface area. CTS-g-PAMA was then applied to treat a series of simulated waste water containing kaolin or Escherichia coli . Flocculation tests indicated that CTS-g-PAMA not only showed excellent flocculation effect but also showed high sterilization capability. A series of ONP concentration measurement tests through UV spectra analysis and 3D EEM analysis of suspension before and after flocculation were conducted to study sterilization mechanism, and results revealed the sterilization effect of CTS-g-PAMA was essentially bactericidal, not just antibacterial. [ABSTRACT FROM AUTHOR]

Extracellular organic matter (EOM) is ubiquitous in the algae-polluted water and has a significant impact on the human health and drinking water treatment. We investigate the different characteristics of dissolved extracellular organic matter (dEOM) and bound extracellular organic matter (bEOM) recovered from the various growth period of Microcystis aeruginosa and the interactions of them and polyaluminum chloride (PACl). The roles of the different EOM in the algae-polluted water treatment are also discussed. The functional groups of aromatic, O H, N H, C N and N O in bEOM possessing the stronger interaction with hydroxyl aluminum compared with dEOM is responsible for bEOM and algae removal. Some low molecular weight (MW) organic components and protein-like substances in bEOM are most easily removed. And dEOM weakly reacts with PACl or inhibits coagulation, especially dEOM with the high MW organic components. The main coagulation mechanisms of bEOM are the generation of insoluble Al-bEOM through complexation, the bridge of AlO 4 Al 12 (OH) 24 (H 2 O) 12 7+ (Al 13 ), the adsorption of Al(OH) 3(am) and the entrapment of flocs. The adsorption of Al 13 and Al(OH) 3(am) mainly contribute to dEOM removal. It is also recommended to treat the algae with dEOM and bEOM at the initial stage. [ABSTRACT FROM AUTHOR]

Flocculation as the core technology of sludge pretreatment can improve the dewatering performance of sludge that enables to reduce the cost of sludge transportation and the subsequent disposal costs. Therefore, synthesis of high-efficiency and economic flocculant is remarkably desired in this field. This study presents a cationic polyacrylamide (CPAM) flocculant with microblock structure synthesized through ultraviolet (UV)-initiated template copolymerization by using acrylamide (AM) and methacrylamido propyl trimethyl ammonium chloride (MAPTAC) as monomers, sodium polyacrylate (PAAS) as template, and 2,2'-azobis [2-(2-imidazolin-2-yl) propane] dihydrochloride (VA-044) as photoinitiator. The microblock structure of the CPAM was observed through nuclear magnetic resonance ( 1 H NMR and 13 C NMR) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM) analyses. Furthermore, thermogravimetric/differential scanning calorimetry (TG/DSC) analysis was used to evaluate its thermal decomposition property. The copolymerization mechanism was investigated through the determination of the binding constant M K and study on polymerization kinetics. Results showed that the copolymerization was conducted in accordance with the I (ZIP) template polymerization mechanism, and revealed the coexistence of bimolecular termination free-radical reaction and mono-radical termination in the polymerization process. Results of sludge dewatering tests indicated the superior flocculation performance of microblock flocculant than random distributed CPAM. The residual turbidity, filter cake moisture content, and specific resistance to filtration reached 9.37 NTU, 68.01%, and 6.24 (10 12 m kg −1 ), respectively, at 40 mg L −1 of template poly(AM-MAPTAC) and pH 6.0. Furthermore, all flocculant except commercial CPAM showed a wide scope of pH application. [ABSTRACT FROM AUTHOR]

[Display omitted] • A type of Fe-based graphite catalyst (Fe-0.6@N-GC) was obtained and characterized. • It shows superior SIZ adsorption capacity due to great S BET and pyridinic N sites. • Fe-0.6@N-GC/PMS system shows satisfactory catalytic performance. • Stable encapsulation of metallic Fe greatly reduce the iron leaching. • Nonradical pathways with promising cycling performance were proposed. In this work, Fe-based graphite catalyst (Fe-0.6@N-GC) was successfully synthesized to degrade sulfisoxazole (SIZ) via peroxymonosulfate (PMS) activation. Fe-0.6@N-GC has large specific surface area and abundant pyridinic N sites, leading to superior SIZ adsorption. Complete degradation of SIZ (5 mg/L) can be achieved within 20 min in the Fe-0.6@N-GC/PMS system. Electrochemical analysis, electron paramagnetic resonance, scavenging and probe experiments illustrated that SIZ can be efficiently degraded via mediated electron transfer pathway from SIZ to PMS, as well as the partial contribution of singlet oxygen (1O 2). Meanwhile, stable encapsulation of scattered Fe sites on N-doped porous carbon greatly reduced the iron leaching (≤0.023 mg/L). High selectivity for different pollutants degradation and tolerance of coexisting ions were performed which is beneficial to practical application. Finally, the possible degradation pathways were also proposed by analyzing intermediates. Overall, this study provides a new understanding of nonradical pathways in organic pollutants oxidation by catalysis of iron-based catalysts. [ABSTRACT FROM AUTHOR]

PO43- and SiO32- are often used as modifier to improve stability and aggregating ability of the iron-base coagulants, however, there are few reports about their detailed comparison between the coagulation performance and mechanisms. In this study, three coagulants—polyferric phosphoric sulfate (PFPS), polysilicon ferric sulfate (PFSS), and polyferric sulfate (PFS) were synthesized; their structure and morphology were characterized by Fourier transformed infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) and Scanning electron microscope (SEM). Alkali titration and Ferron species analysis were employed to investigate the hydrolysis performance and species distribution. Jar test was conducted to measure their coagulation behaviors at different dosage, pH, and temperatures in which the flocs properties were measured. The results showed that a number of new compounds were formed due to the presence of PO43- and SiO32-. Moreover, PFPS and PFSS had similar level in Fea as well as Feb. Among them, PFPS produced more multi-core iron atoms polymer and content of Feb, and the formed flocs were larger and denser. It exhibited superior coagulation performance in terms of turbidity reduction, UV254 removal and residual ferric concentration. Jar test and floc breakage/regrowth experiments indicated other than charge neutrality, the dominated mechanism involved in PFSS was the adsorption between polysilicic acid and solution particle, while PFPS was sweeping, entrapment/adsorption resulting from larger polymer colloid of Fe-P chemistry bond. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new carbon-based bimetallic material, Fe 1 Co 2 @C, was fabricated via calcining cationic resin exchanged with Fe and Co cations. • Fe 1 Co 2 @C exhibited more superior PMS activation performance than monometallic materials (Fe@C and Co@C) to degrade atrazine. • SO 4 •− and •OH were jointly the predominant radical species responsible for ATZ degradation, especially •OH. • −(C − SO 3) x − Co(II) and the synergy between Fe and Co on the Fe 1 Co 2 @C both accelerate redox cycles of Co(II)/Co(III) and Fe(II)/Fe(III). • Atrazine was degraded through dealkylation, dichlorination, hydroxylation, and deamination-hydroxylation processes. Aiming at realizing heavy metal recycling and resource utilization, a carbon-based bimetallic material (Fe 1 Co 2 @C) was fabricated via calcining cationic resin exchanged with Fe and Co cations. It exhibited superior peroxymonosulfate (PMS) activation performance to degrade atrazine (ATZ) compared with the monometallic materials (Fe@C and Co@C). Fe 1 Co 2 @C/PMS performed high degradation of 5 mg/L ATZ with the reaction rate constant (k obs) of 0.0869 min−1 within 30 min of reaction time. The effects of catalyst loading, PMS dosage, initial pH, and the presence of inorganic ions (NO 3 −, SO 4 2− Cl−, and HCO 3 −) and natural organic matters (NOMs) were also investigated in this work. According to the radical quenching experiments and electron paramagnetic resonance (EPR), hydroxyl radical (• OH) and sulfate radical (SO 4 •−) were identified to be the primary reactive oxygen species (ROS) responsible for the ATZ degradation, especially • OH. What's more, reaction mechanism of Fe 1 Co 2 @C was demonstrated that −(C− SO 3) x − Co(II) and the synergy between Fe and Co on the surface could both promote the heterogeneous redox cycles of Co(II)/Co(III) and Fe(II)/Fe(III) to activate PMS. Based on the detection results of intermediates by LC-MS, possible degradation pathways of ATZ included dealkylation, dichlorination, hydroxylation, and deamination-hydroxylation processes were proposed. This research not only provides new insights of PMS activation by carbon-based bimetallic catalyst for water treatment, but also proposes a new way for reusing the waste saturated cation resin waste with heavy metal. [ABSTRACT FROM AUTHOR]

[Display omitted] • Self-floating cyclodextrin-modified polymer was prepared. • The adsorption performance of TFCD and FTFCD was compared. • FTFCD simplified the recycling process by wrapping a hollow glass microsphere. • Porous structure and hydrophobic cavity favor the dye adsorption. • Polymers exhibited excellent selectivity toward cationic dyes. The separation and recycling processes of current cyclodextrin (CD)-based adsorbents are complicated. Thus, a novel composite based on a large surface area, porous, and self-floating tetrafluoroterephthalonitrile (TFN)-crosslinked CD polymer (FTFCD), was fabricated, characterized and applied to treat cationic dye pollutants. The characterization showed a porosity, good thermal stability, a stable crystal structure, and abundant functional groups on the prepared FTFCD, which had demonstrated great improvement on its adsorption capacity towards attention grabbing pollutants. The removal efficiency of the adsorbents for malachite green (MG) remained above 95% at pH 1 ∼ 10. In addition, the adsorbents were found to rapidly reach equilibrium governed by the pseudo-second-order kinetic model, and the maximum adsorption capacity of FTFCD was 1390.263 mg/g, as corroborated by the Langmuir isotherm model. While the phenolate groups of FTFCD found to electrostatically interacts with the MG strong cationic quaternary amine group, hydrogen-bonding was responsible for the hydroxyl group of FTFCD and the quaternary amine group binding. Meanwhile, the triangular cone configuration of MG makes it easy to be entrapped and absorbed in the hydrophobic cavity. Besides, after regeneration of exhausted FTFCD for five successive cycles, the MG removal efficiency still reached more than 80%. Thus, FTFCD could be applied as a potential alternative adsorbent for cationic dye removal owing to its excellent adsorption performance, convenient recycling, wide pH application, and environmental friendliness. [ABSTRACT FROM AUTHOR]

The effects of the cationic surfactant (cationic cetyl trimethyl ammonium bromide, CTAB) on the improvement of the sludge dewaterability using the cationic flocculant (cationic polyacrylamide, CPAM) were analyzed. Residual turbidity of supernatant, dry solid (DS) content, extracellular polymeric substances (EPS), specific resistance to filtration (SRF), zeta potential, floc size, and settling rate were investigated, respectively. The result showed that the CTAB positively affected the sludge conditioning and dewatering. Compared to not using surfactant, the DS and the settling rate increased by 8%–21.2% and 9.2%–15.1%, respectively, at 40 mg·L−1 CPAM, 10×10−3 mg·L−1 CTAB, and pH 3. The residual turbidities of the supernatant and SRF were reduced by 14.6%–31.1% and 6.9%–7.8% compared with turbidities and SRF without surfactant. Furthermore, the release of sludge EPS, the increases in size of the sludge flocs, and the sludge settling rate were found to be the main reasons for the CTAB improvement of sludge dewatering performance. [ABSTRACT FROM AUTHOR]

• Bis-PDI-T@TiO 2 was firstly prepared by a bisolvent phase transfer method. • Carbamazepine was completely removed within 30 min. • SO 4 •−, •OH, O 2 •−, and h+ are responsible for carbamazepine degradation. • Carbamazepine degradation pathway was proposed. Due to the low concentrations of pharmaceuticals and personal care products (PPCPs), traditional water treatment processes are difficult to degrade them effectively. 2,5-bis (tributylstannyl) thiophene-perylene diimide-T@TiO 2 (Bis-PDI-T@TiO 2) composite photocatalyst is firstly prepared by the bisolvent phase transfer method and has a good ability to activate persulfate (PS) under visible light. 5 ppm Carbamazepine (CBZ) (a typical PPCPs) can be completely degraded by 1.0 g/L prepared photocatalyst and 1.0 mM PS within 30 min in the 0.1 wt% Bis-PDI-T@TiO 2 (PT 0.1) system under visible light. Four species of reactive oxidizing species were identified for CBZ degradation, including sulfate radical (SO 4 •−), hydroxyl radical (•OH), superoxide radical (O 2 •−), and positive hole (h+), and all contributed to CBZ degradation. Furthermore, the PT 0.1 photocatalyst exhibits the high stability and recyclability. This study also proposed the reaction mechanism of the Vis/PS/Bis-PDI-T@TiO 2 system and constructed a route of carbamazepine degradation in the coupled system. [ABSTRACT FROM AUTHOR]

An easily separation composite, magnetic chitosan@bismuth tungstate coated by silver (MCTS-Ag/Bi 2 WO 6), was successfully synthesized by the simple hydrothermal method. Moreover, the MCTS-Ag/Bi 2 WO 6 demonstrated excellent adsorption/photocatalytic removal of Cu(II) in aqueous solution. Adsorption played a leading role in the synergistic reaction. The catalysts were characterized by fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and scanning electron microscope (SEM). The effects on adsorption of Cu(II) were investigated, which included illumination, pH, and initial concentration. The experimental results showed that the theoretical maximum adsorption capacity of Cu(II) (181.8 mg/g) was achieved under simulated solar light irradiation with the optimal pH value of 6.0, indicating that illumination could enhance the adsorption of Cu(II) by MCTS-Ag/Bi 2 WO 6. Meanwhile, the composite exhibited desirable adsorption ability of Cu(II) after 5 cycles. The copper ion adsorption fitted well with pseudo-second-order kinetic model and its isotherm followed Freundlich model. Image 1 • A magnetic composites were synthesized by a simple hydrothermal method, and showed easier separation from water. • In MCTS, the active group –COOH and –OH could complex with Cu(Ⅱ), which could effectively remove Cu(Ⅱ). • The absorbent, MCTS, and the photocatalyst, Ag/Bi 2 WO 6 , were combined to improve the adsorption capacity. • MCTS-Ag/Bi 2 WO 6 showed high theoretical adsorption capacity of 181.8 mg/g. [ABSTRACT FROM AUTHOR]

Spinal cord injury (SCI) represents a relatively common type of motor system trauma. While the SCI patient will experience varying degrees of paraplegia and quadriplegia, which severely affects their quality of life, a heavy burden is also placed on the family and society as a whole. The exact pathogenic mechanisms underlying this condition remain unknown and no specific treatments are currently available. Findings from recent studies have shown that mesenchymal stem cells (MSCs), derived from extracellular vesicles (EVs) can reduce apoptosis, inflammation and promote angiogenesis after SCI. However, the mechanisms through which EVs exert these effects have yet to be identified, indicating the necessity for further investigation. In the present study, we report that treatment with MSCs-EVs significantly improved functional recovery and attenuated lesion size and apoptosis in a rat model of SCI. These MSCs-EVs were found to be directed to the spinal injury site and mainly incorporated into neurons within the lesioned site of the spinal cord. Tandem Mass Tags quantitative proteomics was applied to compare protein changes after SCI and MSCs-EVs treatment. A total of 883 differential proteins were identified, many of which being associated with apoptosis and inflammation. Subsequently, miRNA contents of MSCs-EVs were determined using qRT-PCR, with the result that miR-21-5p was one of the most highly expressed miRNA in these MSCs-EVs. Moreover, inhibition of miR-21-5p in MSCs-EVs significantly reversed the beneficial effects of MSCs-EVs on motor function and apoptosis, an effect which was associated with modulating FasL expression. The data suggest that modulation of the MSCs-EVs miR-21-5p/FasL gene axis may serve as a promising strategy for clinical treatment of SCI and other neurological diseases. [ABSTRACT FROM AUTHOR]