Silica gel matrix immobilized Chlorophyta hydrodictyon africanum for the removal of methylene blue from aqueous solutions: Equilibrium and kinetic studies

Chlorophyta hydrodictyon africanum was immobilized on a silica gel matrix to improve its mechanical properties. The algae-silica gel adsorbent was used for batch sorption studies of a cationic dye, methylene blue (MB). Optimum adsorption was obtained with a dosage of 0.8 g bio sorbent. Results from sorption studies show that 124.11 mg·g-1 of MB could be adsorbed at an optimum pH of 8 and immobilization of 300 mg per gram silica. Maximum immobilization was 400 mg biomass per gram silica. Sorption capacity increased with an increase in initial dye concentration and reached equilibrium within 30 min. Three models were used to  simulate kinetic data and the pseudo–second order model gave a better fit with R2 greater than 0.98 in all cases. Equilibrium studies revealed that the adsorption of MB followed Freundlich isotherm (R2=1.00).Key words: Adsorbent, algae, Langmuir model, Freundlich isotherm

Credit Information Sharing and Loan Default in Developing Countries: The Moderating Effect of Banking Market Concentration and National Governance Quality

Departing from the existing literature, which associates credit information sharing with improved access to credit in advanced economies, we examine whether credit information sharing can also reduce loan default rate for banks domiciled in developing countries. Using a large dataset covering 879 unique banks from 87 developing countries from every continent, over a nine-year period (i.e., over 6,300 observations), we uncover three new findings. First, we find that credit information sharing reduces loan default rate. Second, we show that the relationship between credit information sharing and loan default rate is conditional on banking market concentration. Third, our findings suggest that governance quality at the country level does not have a strong moderating role on the effect of credit information sharing on loan default rate

Chemical profiling of antifungal Dicerocaryum senecioides and Diospyros mespiliformis extracts using TLC-p-iodonitrotetrazolium violet assay and GC–MS/MS

Abstract Background Despite the availability of conventional medication for fungal skin diseases, dermatophytic infections are now a major crisis in the whole world due to multidrug resistance. In an effort to search for complementary and alternative remedies, this study evaluated the chemical composition of Dicerocaryum senecioides and Diospyros mespiliformis leaf and fruit extracts, respectively, exhibiting significant in vitro antifungal activity. Ethyl acetate extracts of each plant were screened for antifungal activity against three fungi species: Candida albicans, Trichophyton rubrum and Epidermophyton floccosum using disc diffusion and poisoned food assays. Gas chromatography–tandem mass spectrometry (GC–MS/MS) was used to evaluate the chemical composition after isolation of active bands by thin-layer chromatography-p-iodonitrotetrazolium chloride assay. Results The composite crude ethyl acetate extracts of D. mespiliformis and D. senecioides (1:1) exhibited concentration-dependent antifungal potencies. C. albicans was susceptible to the crude extracts up to a minimum concentration of 6.25%. E. floccosum and T. rubrum were more susceptible up to a minimum extract concentrations of 1%. GC–MS/MS analysis of the isolated active TLC bands revealed bioactive compounds including flavonoids (quercetin, luteolin), together with their O-glycosylated counter parts and the C-monoglycosylated flavonoids (vitexin, orientin, isovitexin and isoorientin), terpenoids, esters and other phenolic acids. Some of the compounds were common to both plants. Conclusion The findings of this study show that D. senecioides and D. mespiliformis extracts consist of important bioactive compounds to warrant their use in complementary and alternative poly-herbal formulations against fungal infections

Removal of lead (II) and copper (II) ions from aqueous solution by baobab (Adononsia digitata) fruit shells biomass

High concentration of heavy metals in the environment can be detrimental to a variety of living species. The purpose of this research was to explore the use of baobab (Adsononsia digitata) fruit shells in the removal of lead(II) and copper(II) ions from aqueous solutions. Batch experiments were conducted to determine the effect of varying adsorption parameters on the removal of aqueous lead and copper ions. The adsorption of Pb(II) was found to be maximum at pH 5.5 using adsorbent dose of 0.7 g. The adsorption of Cu(II) was found to be optimum at pH 6 using adsorbent dosage of 0.9 g. The adsorption data conformed to Langmuir, Freundlich and Temkin isotherms. However the Temkin isotherm showed the best fitting model with highest R2 values for both lead and copper (0.9977 and 0.9967) respectively. Baobab fruit shells can be used as a cost effective adsorbent for the removal of lead(II) and copper(II) ions from aqueous solutions in the treatment of industrial effluent