Search

[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]

[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]

[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]

• 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]