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Considering the high cost and complicated recycling process of spent lithium-ion batteries (SLIBs), transforming SLIBs into environment functional materials may be a wise approach. Herein, lithium cobaltite (LCO) cathode powders recovered from SLIBs were used to activate peroxymonosulfate (PMS) for removing carbamazepine (CBZ). The recovered LCO enables a 98.2% removal efficiency of CBZ (2.5 mg/L) within 10 min, which was effective at a broader pH range (pH = 5.0-11.0). The influence of key factors (initial pH, PMS, and catalyst dosage) and coexisting substances (SO42-, H2PO4-, NO3-, Cl-, HCO3-, and HA) on CBZ degradation were examined in detail. The primary radical species during the degradation of CBZ were proved to be 1O2, SO4-, and.OH that generated from PMS activation initiated by the valence change of Co in recovered LCO. The recovered LCO displayed excellent reusability with about 80.0% removal of CBZ after six cycles. Homogeneous activation of PMS mainly contributed to CBZ degradation in the first run, but the recovered LCO catalyst dominated the heterogeneous activation of PMS for the degradation of CBZ in the second to sixth run. Finally, the CBZ degradation pathways were presented based on the identified intermediates. This research has offered a new strategy of "treating wastes with wastes" to maximize the recycling of electronic wastes to remove emerging pollutants.

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Herein, a heterogeneous photo-Fenton and photo-catalytic system was constructed using oxide pyrite (FeS2/Fe2O3) mineral and organic acids including tartaric acid (TA), ascorbic acid (AA), and citric acid (CA). In the proposed system, FeS2/Fe2O3 can be successfully activated through irradiation to generate photogenerated carriers, which generated H2O2in-situ through the reduction reactions between e- and O2. The addition of organic acids enhanced the dissolution of iron from FeS2/Fe2O3. Based on the iron and in-situ generated H2O2, •OH was produced through a photo-Fenton reaction. Furthermore, h+, e-, and •O2-, which were generated through the photo-catalytic activation of FeS2/Fe2O3, also played a certain role in the degradation of carbamazepine (CBZ). Therefore, the synergistic photo-Fenton and photo-catalytic reaction improved the degradation of CBZ, with the degradation efficiencies of 86%, 62%, and 68% in FeS2/Fe2O3/TA, FeS2/Fe2O3/AA, and FeS2/Fe2O3/CA systems, respectively. This investigation provides an innovative strategy for the removal of organic pollutants using natural minerals.

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Pyrite is widely used in Fenton reaction for degradation of pollutants and exhibits great potential for environmental remediation, however, its efficiency is greatly compromised by extra H2O2 and pH adjustment. Herein, a pyrite based green solar photo-Fenton system for carbamazepine (CBZ) treatment is constructed, involving the use of simulated sunlight and natural organic acids with in situ-generated H2O2 and without extra pH adjustment. The addition of organic acids including tartaric acid (TA), citric acid (CA), and ascorbic acid (AA) can form complex with iron in pyrite, which promotes the Fe(II) dissolution. Upon irradiation, pyrite could be excited to produce photoelectrons, which would reduce oxygen to produce H2O2 through a two-step route assisted by organic acids. The simulated sunlight and organic acids promoted the in-situ production of H2O2 and Fe(II) species, sustaining an efficient Fenton reaction. This produced massive hydroxyl radical (OH), as demonstrated by the active species capture experiment. Compared with no degradation of CBZ under pure pyrite, the degradation efficiency of CBZ reached to 70%, 60%, and 53% in pyrite/TA, pyrite/CA, pyrite/AA within 30 min under simulated solar light irradiation, respectively. This work reports the first use of natural pyrite, a typical Fe-mineral semiconductor, to produce OH for CBZ degradation through natural additive assisted Fenton reaction excluding the adding extra H2O2 and pH adjustment.

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Fridericia bulbosa (Rosa, 1887) was proposed as a new test species to assess soil ecotoxicity. The acute toxicity of mercury (Hg) and bromoxynil (BX) on the mortality of Fridericia bulbosa (F. bulbosa) in OECD soil was investigated. The results suggested there were statistically significant differences (p<0.05) between controls and treatments except lower concentration of exposure to single pollutant. BX was more toxic to F. bulbosa than Hg. The 14 d LC(50) values for F. bulbosa exposed to Hg and BX were 3.87 and 2.41 mg kg(-1), respectively. The effects of mixtures with single pollutants on earthworms were observed differently. Toxicity of Hg on earthworms was significantly influenced by the concentration of BX. BX was the main contributive factor of the combined toxic effects. It can be proved that F. bulbosa is a suitable bio-indicator to measure the acute toxicity of mixed pollutants in soil and the mortality of earthworms may be considered as a valuable and sensitive biomarker to diagnose adverse effect of Hg or BX in soil environment.

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Chemicals in the environment often exist as mixtures and at low doses, whose ecotoxicological diagnosis and risk assessment are hard to be done with the help of the research results on the ecotoxicity of high-level exposure of single chemicals. This paper reviewed the research advances in ecotoxicology and risk assessment of low-dose chemical mixture contamination, with the focus on the molecular toxicological methods and the risk assessment approaches and schemes of simple and complex mixtures. Comments were given on the development directions of low-dose chemical mixture research, including the necessity of searching for sensitive endpoints, involving the approaches of other disciplines, increasing data accumulation, and setting up a comprehensive and identical risk assessment system.

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