Copper remediation by Eichhornia spp. and sulphate-reducing bacteria

Eichhornia spp. biomass was collected from Chandola Lake, Ahmedabad, Gujarat, India. Point of zero charge of the biomass was pH 7.3. Flask study showed pH 5 and 2–3 h contact time as optimum conditions for copper sorption with 67.25% copper removal. At the end of 24 h of contact time, copper removal reached to 85.0%, from 100 ppm copper containing solution. Copper loading capacity of the biomass ranged between 9.9 and 28.5 mg g^?1 of biomass. To understand the interaction among pH, temperature, presence of nickel and zinc in the system, 2⁴ factorial experiment was performed. Under the experimental conditions pH and interactions between pH–nickel, temperature–pH and temperature–pH–nickel–zinc were found to be significant with 60–74.7% copper removal. Langmuir isotherm was better fit as compared to Freundlich isotherm and pseudo-second order equation gave R² of 0.999 for biosorption kinetic of Eichhornia biomass. Reactor study showed 90% overall copper removal from 24 L of copper containing waste studied and sulphate-reducing bacteria played a significant role. SEMquant element analysis showed increase from 41.66% to 53.93%, 1.02–19.73% and 0.0–12.39% of chloride, aluminium and copper respectively in the loaded biomass as compare to unexposed biomass.     

Decouple and compare the role of abiotic factors and developed iron and sulphur oxidizers for enhanced extraction of metals from television printed circuit boards

Chemical leaching agents were compared for metal extractions from selected e-waste. Effect of iron, sulphur oxidizers and the formulated consortium were investigated for metals extraction from television printed circuit boards. The consortium showed maximum metal leaching efficiency. The bioleaching profile was studied as a function of pH, redox potential, acid consumed and the amount of Cu, Zn and Ni extracted. At 10 g/L of e-waste, 90%, 93% and 87% of Cu, Zn and Ni were extracted within 96 h. Ethylene diamine tetra acetic and pyrite were found beneficial. Two-step process resulted in more metal extraction even at 100 g/L pulp density.     

Acrylate-based transdermal therapeutic system of nitrendipine

The objective of the present research investigation was to fabricate an acrylate-based transdermal therapeutic system (TTS) of nitrendipine, which could deliver drug at maximum input rate so as to deliver drug in minimum patch size. Transdermal patches were fabricated using synthesized acrylate pressure-sensitive adhesives (PSAs): PSA1, PSA2, and commercially available PSA3 and PSA4 using d-limonene as permeation enhancer. Effect of concentration of d-limonene on permeation kinetics of nitrendipine in PSAs was studied. Fabricated TTS in mentioned PSAs were evaluated for in-vitro release and permeation kinetics through guinea-pig skin. Cumulative release of drug in PSA1, PSA2, PSA3, and PSA4 was observed to be 45%, 40%, 25%, and 25%, respectively, upto 24 hr. Flux of drug through guinea-pig skin calculated at 48 hr in PSA1, PSA2, PSA3, and PSA4, with and without d-limonene, was observed to be 0.346 ± 0.10, 0.435 ± 0.17, 0.410 ± 0.17, and 0.162 ± 0.06, and 0.625 ± 0.19, 1.161 ± 0.46, 0.506 ± 0.17, and 0.520 ± 0.18 (µg/cm²/hr), respectively. The TTS in PSA2 showed comparatively high flux and could deliver drug at high input rate through transdermal route. PSA2 was found to have good rate-controlling property and could be successfully employed in transdermal delivery of nitrendipine.