Bimetallic carbon nanotube encapsulated Fe-Ni catalysts from fast pyrolysis of waste plastics and their oxygen reduction properties

Carbon-based bimetallic electrocatalysts were obtained by catalytic pyrolysis of waste plastics with Fe-Ni-based catalysts and were used as efficient oxygen reduction reaction (ORR) catalysts in this study. The prepared iron-nickel alloy nanoparticles encapsulated in oxidized carbon nanotubes (FeNi-OCNTs) are solid products with a unique structure. Moreover, the chemical composition and structural features of FeNi-OCNTs were determined. The iron-nickel alloy nanoparticles were wrapped in carbon layers, and the carbon nanotubes had an outer diameter of 20–50 nm and micron-scale lengths. FeNi-OCNT with a Fe/Ni ratio of 1:2 (FeNi-OCNT12) exhibited remarkable electrochemical performance as an ORR catalyst with a positive onset potential of 1.01 V (vs. RHE) and a half-wave potential of 0.87 V (vs. RHE), which were comparable to those of a commercial 20% Pt/C catalyst. Furthermore, FeNi-OCNT12 exhibited promising long‐term stability and higher tolerance to methanol than the commercial 20% Pt/C catalyst in an alkaline medium. These properties were attributable to the protective OCNT coating of the iron-nickel alloy nanoparticles

Contrasting plant–microbe interrelations on soil Di-(2-ethylhexyl) phthalate and pyrene degradation by three dicotyledonous plant species

Plants and associated microbial communities can actively participate in the biodegradation of organic pollution. Potexperiments were conducted to explore the plant–microbe interrelations on Di-(2-ethylhexyl) phthalate (DEHP) and pyrene degradation in a soil culture system. Three dicotyledonous plant species, Ceylon spinach (Gynuracusimbua (D. Don) S. Moore), sunflower (Helianthus annuus L.), and Shuidong mustard (Brassica juncea (L.) Coss.var. foliosa Bailey), were cultivated for 45 days in DEHP and pyrene co-contaminated soils using three initial content levels: 0 (T0), 20 (T20) and 50 mg kg−1 (T50) with no plants (NP) as control. The results demonstrated that Shuidong mustard biomass and sunflower biomass had significantly positive correlations with the removal rate of DEHP (P < .05), respectively, while Ceylon spinach biomass has no significant correlation with the removal rate of DEHP. Shuidong mustard–actinomycetes and Ceylon spinach–actinomycetes accelerated the removal rate of pyrene, and sunflower–gram-positive bacteria could also enhance the removal rate of pyrene. Our results suggest that a better understanding of plant–microbe interrelations could be exploited to enhance the phytoremediation of organic co-contaminated soils

Responses of soil microbial community and enzymes during plant-assisted biodegradation of di-(2-ethylhexyl) phthalate and pyrene

A pot experiment was conducted to explore the plant-assisted degradation efficiency of di-(2-ethylhexyl) phthalate (DEHP) and pyrene. Three plant species: Ceylon spinach, sunflower, and leaf mustard were cultivated in co-contaminated soils under three contamination levels: control (T0), 20 mg kg−1 (T20), and 50 mg kg−1 (T50). The results showed that a higher DEHP and pyrene degradation efficiency was observed evidently in planted cases, increasing from 42 to 53–59% (T0), 61 to 65–76% (T20) and 52 to 68–78% (T50) for DEHP, and from 22 to 30–49% (T0), 58 to 62–72% (T20), and 54 to 57–70% (T50) for pyrene. Under T20 contamination level, soil phospholipid fatty-acid analysis depicted the increased microbial biomass in rhizosphere, especially the arbuscular mycorrhizal fungus that is effective for the degradation of organic pollutants. The study also revealed that the activities of dehydrogenase, acid phosphomonoesterase, urease, and phenol oxidase negatively correlated with pollutant concentration. In general, the removal rate of DEHP and pyrene was highest in the soil planted with leaf mustard for each contamination level considered. For soils at T20 level, sunflower and leaf mustard appeared as interesting phytoremediation plants due to the improved removal rates of organic pollutants and the soil microbial activity