Removal of copper from acid wastewater of bioleaching by adsorption onto ramie residue and uptake by Trichoderma viride

Bioremediation and tolerance of zinc ions using Fusarium solani

Evaluating the mechanism of tolerance and biotransformation Zn(II) ions by Fusarium solani based on the different physiological was the objective of this work. The physical properties of synthesized ZnONPs was determined by UV-spectroscopy, transmission electron microscope, and X-ray powder diffraction. The structural and anatomical changes of F. solani in response to Zn(II) was examined by TEM and SEM. From the HPLC profile, oxalic acid by F. solani was strongly increased by about 10.5 folds in response to 200 mg/l Zn(II) comparing to control cultures. The highest biosorption potential were reported at pH 4.0 (alkali-treated biomass) and 5.0 (native biomass), at 600 mg/l Zn(II) concentration, incubation temperature 30 °C, and contact time 40 min (alkali-treated biomass) and 6 h (native biomass). From the FT-IR spectroscopy, the main functional groups implemented on this remediation were C-S stretching, C=O C=N, C-H bending, C-N stretching and N-H bending. From the EDX spectra, fungal cellular sulfur and phosphorus compounds were the mainly compartments involved on ZN(II) binding.

Potential of Trichoderma koningii to eliminate alachlor in the presence of copper ions

The filamentous fungus Trichoderma koningii is capable of fast and effective eliminate alachlor (90% after 72 h when added separately and 80-60% in the presence of 1-5 mM of copper). After 168 h over 99% elimination of alachlor resulted in detoxification and was connected with the mitigation of reactive oxygen species (ROS) production. Using MS/MS techniques, seven dechlorinated and hydroxylated metabolites were identified. Cytochrome P450 and laccase participate in biotransformation of the herbicide by this non-ligninolytic fungus. Laccase activity is stimulated both by copper and the mixture of copper and alachlor, which seems to be important for combined pollutants. T. koningii is characterized by high tolerance to copper (up to 7.5 mM). The metal content in mycelia reached 0.9-7.76 mg in 1 g of dry biomass. Our results suggest that T. koningii strain seems to be a promising tool for bioremediation of agricultural areas co-contaminated with copper-based fungicides and chloroacetanilide herbicides.

Assessment of Ni accumulation capability by fungi for a possible approach to remove metals from soils and waters

Abandoned industrial sites and mines may constitute possible hazards for surrounding environment due to the presence of toxic compounds that may contaminate soils and waters. The possibility to remove metal contaminants, specifically nickel (Ni), by means of fungi was presented exploiting a set of fungal strains isolated from a Ligurian dismissed mine. The achieved results demonstrate the high Ni(II) tolerance, up to 500 mg Ni l^-1, and removal capability of a Trichoderma harzianum strain. This latter hyperaccumulates up to 11,000 mg Ni kg^-1, suggesting its possible use in a bioremediation protocol able to provide a sustainable reclamation of broad contaminated areas.

Investigation of the adsorption-reduction mechanisms of hexavalent chromium by ramie biochars of different pyrolytic temperatures

To investigate the relationship between Cr(VI) adsorption mechanisms and physio-chemical properties of biochar, ramie residues were oxygen-limited pyrolyzed under temperature varying from 300 to 600°C. Batch adsorption experiments indicated that higher pyrolysis temperature limits Cr(VI) sorption in terms of capacity and affinity due to a higher aromatic structure and fewer polar functional groups in biochar. Both electrostatic (physical) and ionic (chemical) interactions were involved in the Cr(VI) removal. For low-temperature biochar, the simple physical adsorption was limited and the significant improvement in Cr(VI) sorption was attributed to abundant carboxyl and hydroxyl groups. The adsorption-reduction mechanisms could be concluded that Cr(VI) ions were electrostatically attracted by the positively charged biochar surface and reduced to Cr(III), and then the converted Cr(III) was retained or discharged into the solution. The study demonstrates ramie residues can be converted into biochar as a low-cost and effective sorbent for Cr(VI) removal.

Microfungi in highly copper-contaminated soils from an abandoned Fe-Cu sulphide mine: growth responses, tolerance and bioaccumulation

Copper is one of the most dangerous soil contaminants. Soils affected by high copper concentrations show low biodiversity and, above all, inadequate environmental quality. Microorganisms such as fungi can play a key role in metal-polluted ecosystems via colonization and decontamination. The study is devoted to characterize the microfungal community in highly Cu-contaminated bare soil from derelict Fe-Cu sulphide mines and to isolate microfungal strains able to tolerate and accumulate Cu. 11 Different taxa to be isolated has been isolated during two sampling campaigns (in Autumn and in Spring). Among these, Clonostachys rosea, Trichoderma harzianum, and Aspergillus alliaceus were tested at increasing Cu(II) concentrations and showed a Cu(II)-tolerance capability ranging from 100 to 400 mg L(-1). Moreover, the strains of T. harzianum and C. rosea presented a high Cu(II)-bioaccumulation capability, 19628 and 22,222 mg kg(-1), respectively. These microfungi may be fruitfully exploited in mycoremediation protocols.

Biosorption of antimony(V) onto Fe(III)-treated aerobic granules

Iron precipitate was produced with 0.1M FeCl3 and bound with the amino or hydroxyl groups of the granules surface, accompanied with removal of Ca, Mg, K and Na from the biomass matrix. The Fe(III)-treated granules exhibited much higher adsorption capacity of antimony(V) than the untreated granules, peaked at pH 3.4 at a maximum capacity of 22.6 mg g(-1) of dry mass. The intraparticle diffusion and film diffusion resistances controlled the Sb(V) adsorption onto the Fe(III)-treated granules. Fe(III) treatment is a cost-effective and easy-to-implement process to modify the surface of aerobic granules to enhance their adsorption capacity to Sb(V).