Rhizosphere microbiome of plants used in phytoremediation of mine tailing dams.

Rhizospheric microbial communities improve the effectiveness of hyperaccumulators in the phytoremediation of heavy metals. However, limited access to tailing dams and inadequate assessment of plants' phytoremediation potential limit the characterization of native accumulators, hindering the effectiveness of local remediation efforts. This study evaluates the heavy metal sequestration potentials of Pennisetum purpureum, Leucaena leucocephala, and Pteris vittata and their associated rhizospheric microbial communities at the Marlu and Pompora tailing dams in Ghana. The results indicate shoot hyperaccumulation of Cd (334.5 ± 6.3 mg/kg) and Fe (10,647.0 ± 12.6 mg/kg) in P. purpureum and L. leucocephala, respectively. Analysis of rhizospheric bacterial communities revealed the impact of heavy metal contamination on bacterial community composition, associating Fe and Cd hyperaccumulation with Bacillus, Arthrobacter, and Sphingomonas species. This study reports the hyperaccumulation potentials of L. leucocephala and P. purpureum enhanced by associated rhizosphere bacterial communities, suggesting their potential application as an environmentally friendly remediation process of heavy metals contaminated lands.

The novelty of this study is the report of the heavy metal accumulation potentials of the fast-growing herbaceous plants Leucaena leucocephala and Pennisetum purpureum at abandoned gold mine tailing dams in Ghana. Substantial amounts of Cd (334.5 mg/kg) and Fe (10,647.0 mg/kg) were accumulated in P. purpureum and L. leucocephala shoots, indicating their hyperaccumulation potentials. The concentration of heavy metal levels in the rhizosphere influenced the bacterial community structure, with the abundance of Bacillus, Arthrobacter, and Sphingomonas linked to hyperaccumulation. The outcome of this study supports the utilization of L. leucocephala and P. purpureum in the phytoremediation of lands contaminated with heavy metals.

Studies on structure property relations of efficient decal substrates for industrial grade membrane electrode assembly development in pemfc.

Electrode fabrication and membrane electrode assembly (MEA) processes are critical steps in polymer electrolyte membrane fuel cell (PEMFC) technology. The properties of decal substrate material are important in decal coating technique for efficient transfer of catalyst layer. In the present study, MEAs are fabricated in decal method using 6 different decal substrates among which polypropylene (PP) is found ideal. Morphological, thermal, spectroscopic and sessile drop measurements are conducted for 6 decal substrates to evaluate the thermal and physicochemical properties. Studies indicate PP is thermally stable at hot-press conditions, having optimal hydrophobicity that hinders the coagulation of catalyst ink slurry cast. The pristine PP film has been identified to showcase 100% transfer yield onto the Nafion membrane without contamination and delamination of catalyst layer from membrane. The PP based MEAs are evaluated underconstant current mode in a hydrogen-oxygen fuel cell test fixture. The performance is found to be of 0.6 V at a constant current density of 1.2 A.cm-2. Besides, the cost of PP-film is only 7.5% of Kapton-film, and hence the current research work enables the high throughput electrode fabrication process for PEMFC commercialization.