Synergistic activation of peroxydisulfate by photothermal and FeS2-loaded air-laid cloth in a shallow continuous flow reactor

Synergistic activation of persulfate by photothermal and solid catalysts is an effective method for degrading organic pollutants. However, the batch reaction mode not only fails to fully utilize photothermal, but also makes it hard to separate the solid catalysts from the reaction solution. In this work, a shallow continuous flow way of effluent was set up for synergistic activation of peroxydisulfate (PDS) by photothermal and FeS2-loaded air-laid cloth (FeS2-ALC). The degradation efficiency of carbamazepine (CBZ) was significantly enhanced with a pseudo-first-order kinetic constant of 0.0359 min-1, which is 180, 40 and 10 times higher than that of the photothermal/ALC, photothermal/FeS2-ALC and photothermal/PDS processes, respectively. The enhanced efficiency was partly due to the absorption of sunlight by FeS2-ALC to heat up the reaction solution which in turn can use photothermal to activate PDS, and partly due to the activation of the PDS by Fe2+ from FeS2-ALC and the promotion of Fe3+/Fe2+ cycling via S2-. Parameters such as reaction conditions, hydraulic conditions and water quality parameters affecting degradation efficiency were investigated. A possible degradation pathway was proposed and the toxicities of byproducts were tested. Finally, cycling experiments and outdoor experiments demonstrated that the photothermal/FeS2-ALC/PDS process has potential for practical wastewater treatment.

FeS2 nanoparticles decorated carbonized Luffa cylindrica as biofilm substrates for fabricating high performance biosensors

A high-performance microbial biosensor was fabricated with a reasonably designed biofilm substrate, where the aerogel of carbonized Luffa cylindrica (LC) was used as the scaffold for loading biofilm and FeS₂ nanoparticles (FeS₂NPs) were employed to modify this aerogel (FeS₂NPs/Gel_LC). The fabricated FeS₂NPs/Gel_LC exhibited a spring-like structure similar with that of the raw LC, which facilitated the linkage of the scaffold and promoted its mechanical strength, and further prolonged the service period of the as-prepared biosensor from few days to two months. Meanwhile, the introduced FeS₂NPs improved the microbial electron transfer of the biofilm and causing an increase in the sensor's signals from 155.0 ± 2.6 to 352.0 ± 17.1 nA and a decrease in the detection limit from 0.95 to 0.38 mg O L^-1 (S/N = 3) for the detection of glucose-glutamic acid (GGA). More important, the FeS₂NPs had been demonstrated to have the capability for modulating a persistent shift of the microbial community with organic pollutant biodegradability. Compared with the Gel_LC, the FeS₂NPs/Gel_LC exhibited a promising performance for measuring the synthetic sewage and real water samples in BOD assay and an increasing inhibition-ratio for detecting 3,5-dichlorophenol (DCP) in toxicity assay. Based on the vast resource and renewability of LC, this work pave a new avenue for developing high-performance microbial biosensors that are expected to be the engineering production.

Elucidating "screw dislocation"-driven film formation of sodium thiosulphate with complex hierarchical molecular assembly

Sodium thiosulphate (Na₂S₂O₃) films were synthesized on carbon steel substrates through solution deposition, and a film formation growth mechanism is delineated in detail herein. Dislocation-driven film formation took place at the lower concentration of Na₂S₂O₃ (0.1 M) studied, where screw dislocation loops were identified. Interestingly, we observed the co-existence of screw dislocation spiral loops and hierarchically-ordered molecular assembly in the film, and showed the importance of hierarchical morphology in the origin of screw dislocation. The screw dislocation loops were, however, distorted at the higher studied concentration of Na₂S₂O₃ (0.5 M), and no hierarchical structures were formed. The mechanisms of film formation are discussed in detail and provide new insights into our understanding regarding morphology of the hierarchical molecular assembly, screw dislocation loop formation, and the role of chemical elements for their development. The main crystalline and amorphous phases in the surface films were identified as pyrite/mackinawite and magnetite. As sodium thiosulphate is widely used for energy, corrosion inhibition, nanoparticle synthesis and catalysis applications, the knowledge generated in this study is applicable to the fields of corrosion, materials science, materials chemistry and metallurgy.

P, Kumar M, Thakur A, Bala R, Kumar A. Electrochemical aspects of photocatalysis: Au@FeS2 nanocomposite for removal of industrial pollutant

A wide range of endeavors have been dedicated to building up an impetus in the field of catalysis to enhance the removal of toxic contaminants from water.

The seed stimulant effect of nano iron pyrite is compromised by nano cerium oxide: regulation by the trace ionic species generated in the aqueous suspension of iron pyrite

A brief seed pretreatment of 12 hours, in an aqueous suspension of synthesized nano iron pyrite (FeS₂), significantly increases the yield of spinach and other crops.