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This study reports useful application of biodegradable polymeric materials functionalized with silver nanoparticle (AgNPs) biosynthesized from cocoa pods as effective adsorbent for dye wastewater purification. Corn starch and hen feather were functionalized with AgNPs for adsorption of rhodamine B (Rh-B). All adsorbents were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray diffraction. Decreased intensities of peaks, superior rougher cavities and smaller grain diameter of functionalized biomaterials affirmed the functionalization. Effects of pH, contact time, initial Rh-B concentrations and temperature were investigated and found to be significantly important. Four isotherm models were used to describe the adsorption process with Freundlich being the most suitable for all adsorbents indicating Rh-B adsorbed on heterogeneous multilayer surfaces of adsorbents. AgNPs modification greatly enhanced maximum monolayer adsorption capacities (q max) of feather (4.27-56.53 mg g −1) and starch (1.176-48.60 mg g −1) by 30-and 40-fold respectively. Kinetic rates of adsorption for starch best fitted Elovich, pseudo first order for feather whereas pseudo second order best suitable for starch-AgNPs and feather-AgNPs. Energies (3.89-7.68 kJ mol −1) of adsorption suggest that adsorption of Rh-B onto the adsorbents was by physiosorption. The negative values of ∆H° and ∆G° imply that adsorption processes were exothermic and spontaneous. Results in this study show that surface functionalization of starch and feather improved their adsorptive performances and will find valuable applications in dye remediation due to their biodegradability and cost-effectiveness.

Zinc oxide nanoparticles (ZnONPs) from plant origin were postulated to regulate complex hormonal control through the hypothalamus– pituitary–testicular axis and somatic cells due to their unique small size and effective drug delivery to target tissues. This study therefore investigates the biogenic synthesis of zinc oxide nanoparticles (ZnO NPs) from Moringa oleifera leaves on key endocrine hormones (LH, FSH and testosterone), MDA level, antioxidant enzymes (SOD and CAT), acetylcholineesterase (AChE) activity and reactive nitrogen species (NO • ) level in rotenone induced male rat. The animals were divided into six groups (n = 8). Group I was orally given olive oil as vehicle; Group II received 60 mg/kg of rotenone (RTNE) only; Group III (RTNE + ZnONPs) received 60 mg/kg RTNE + 10 mg/kg ZnONPs; Group IV (RTNE + ZnCAP) received 60 mg/kg RTNE + 50 mg/kg zinc capsule; Group V (ZnONPs only) received 10 mg/kg ZnONPs only. Group VI received 50 mg/kg ZnCAP only. The experiment lasted 10 days. TEM and XRD images revealed ZnO NPs. Moreover, the presence of organic molecules in bio-reduction reactions from the FTIR spectrum showed the stabilization of the nanoparticles. Also, animals induced with rotenone exhibited impairment in the leydig cells by depleting LH, FSH, and testosterone levels with reduced AChE activity and significant (p < 0.05) alteration in cerebral enzymatic antioxidants. There was also brain increase in NO • production: marker of pro-inflammation. Nanotherapeutically, ZnONPs regulated hypothalamus–pituitary–testicular axis via modulation of cerebral NO • , FSH, LH, testosterone and AChE activity with induction of anti-oxidative enzymes.

Cadmium telluride (CdTe) is a direct band gap semiconductor for direct light-to-electricity conversion. The films are promising photovoltaic materials for CdS/CdTe solar cells because of its energy band gap of 1.5 eV and higher absorption co-efficient (>104cm-1). This work presents the characterization of 1 μm CdTe films for photovoltaic applications. The films were deposited on cleaned glass substrates using thermal evaporation. The effect of annealing temperatures (as deposited, 400°C and 500°C) on morphological, structural and optical characteristics of CdTe films was investigated for an hour and characterized with Scanning Electron Microscope (SEM), Powder X-ray diffraction (PXRD) and UV-Visible spectrophotometer. The results revealed that the reflectance characteristics of CdTe films depend on the wavelength of electromagnetic spectra. The maximum percentage optical transmittance of CdTe films for as-grown, 400°C and 500oC films were 59%, 60% and 58% respectively at 800 nm wavelength. The absorbance decreases with increasing in wavelength and was found to be 1.65, 1.25 and 0.85 % for the as-grown, 400°C and 500oC films respectively. The absorption coefficient exhibits higher values in the shorter wavelength and decreases as the wavelength and temperatures increases and the band gap becomes wider. The SEM analyses showed that the films were homogenous and free from crystal defects. The results revealed that 1 μm CdTe film may be used as absorber layer in CdS/CdTe thin film solar cells. Keywords: CdTe, Glass substrate, Thermal evaporation, Annealing temperature, Energy band gap

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