Evolution of humic substances and the forms of heavy metals during co-composting of rice straw and sediment with the aid of Fenton-like process.

The Fenton-like process was established by Fe3O4 nanomaterials (NMs) and Phanerochaete chrysosporium or oxalate, and applied to the co-composting of rice straw and sediment to study its effect on the formation of humic substance and the bioavailability of Cd, Cu, and Pb. Results shown that the application of Fenton-like process significantly promoted the passivation of Cd and Cu, while not shown obvious enhancement for Pb. The decrease of exchangeable fraction Cd (EXC-Cd) and the humic acid (HA) content in pile B with Fe3O4 NMs and oxalate were highest, which were 22.35% and 20.3 g/kg, respectively. Redundancy analyses (RDA) manifested that the Fenton-like process enhanced the influence of humus substance on the bioavailability of Cd, Cu, and Pb. Excitation-emission matrix (EEM) fluorescence spectra analysis suggested that Fenton-like process could obviously enhance the generation of humic substance. This research provides a new perspective and way for composting to remediate heavy metals pollution.

Deciphering the Fenton-reaction-aid lignocellulose degradation pattern by Phanerochaete chrysosporium with ferroferric oxide nanomaterials: Enzyme secretion, straw humification and structural alteration.

Nowadays, Nano-biotechnology is emerging to be one of the most promising tools in environmental remediation. In this study, the degradation efficiency of lignocellulose by white-rot fungi was improved by addition of Fe3O4 nanomaterials (NMs) in solid-state fermentation. The highly-ordered cellulose crystalline was demonstrated to be broken down through infrared spectroscopy (FT-IR) and crystallinity index analysis. The decay of fluorescence intensity presented a lower degree of aromatic polycondensation and less conjugated chromophores in lignocellulose. Mechanistic analysis showed that NMs participated in the Fenton reaction and affected lignocellulose biodegradation process by regulating enzyme secretion. Specifically, the time variation curves of hydroxyl radicals and Fe2+ were discussed to illustrate the degradation pattern. The NMs remained stable after the fermentation and were possible to be recycled for the next cycle. All the results support that the synergism of Fe3O4 NMs and white-rot fungi would be a promising research direction in lignocellulose treatment.

Comparative study of nano and bulk Fe3O4 induced oxidative stress in Wistar rats.

CONTEXT: Magnetic nanomaterials (Fe3O4 NMs) have become novel tools with multiple biological and medical applications because of their biocompatibility. However, adverse health effects of these NMs are of great interest to learn. OBJECTIVE: This study was designed to assess the size and dose-dependent effects of Fe3O4 NMs and its bulk on oxidative stress biomarkers after post-subacute treatment in female Wistar rats. METHODS: Rats were daily administered with 30, 300 and 1000 mg/kg b.w. doses for 28 d of Fe3O4 NMs and its bulk for biodistribution and histopathological studies. RESULTS: Fe3O4 NMs treatment caused significant increase in lipid peroxidation levels of treated rats. It was also observed that the NM treatment elicited significant changes in enzyme activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase  and glutathione-S-transferase in treated rat organs with major reduction in glutathione content. Metal content analysis revealed that tissue deposition of NM in the organs was higher when compared to bulk and caused histological changes in liver. CONCLUSION: This study demonstrated that for same dose, NM showed higher bioaccumulation, oxidative stress and tissue damage than its bulk. The difference in toxic effect of Fe3O4 nano and bulk could be related to their altered physicochemical properties.

A novel ECL biosensor for the detection of concanavalin A based on glucose functionalized NiCo2S4 nanoparticles-grown on carboxylic graphene as quenching probe.

An electrochemiluminescence (ECL) biosensor was developed for detection of Concanavalin A (Con A). Chitosan/Ru(bpy)32+/silica/Fe3O4 nanomaterials (CRuSi-Fe3O4) were synthesized through W/O microemulsion route. The added Fe3O4 nanoparticles can simplify the prepared process and enhance the conductivity of nanomaterials which can increase the ECL intensity of luminophor CRuSi-Fe3O4. In addition, the layered structure of CRuSi-Fe3O4 can immobilize lots of Con A using glutaraldehyde as the coupling agent which can improve the sensitivity of the biosensor. Then the quenching probe glucose functionalized NiCo2S4 nanoparticles-grown on carboxylic graphene (NiCo2S4-COOH-rGO@Glu) was anchored on the modified-electrode via the specific carbohydrate-Con A interaction. Here, NiCo2S4 was used to quench the ECL of CRuSi-Fe3O4, graphene was used to grow NiCo2S4 nanoparticles as carrier materials and glucose was served as the recognition element for bounding Con A. Therefore, a desirable quenching ECL signal was measured with S2O82- as the coreactant of CRuSi-Fe3O4. Under the optimization of determination conditions, a linear response range for Con A from 0.5pgmL-1 to 100ngmL-1 was obtained, and the detection limit was calculated to be 0.18pgmL-1 (S/N=3).