Effect of chemical extractants on the biosorptive properties of pine cone powder: Influence on lead(II) removal mechanism

AbstractThis study examines the changes in surface properties and lead(II) adsorption mechanism of pine cone powder modified using varying ratios of toluene–ethanol mixtures.Increasing the ratio of toluene in the extractant mixture increased formation of esters and iodine capacity of the material, but reduced carboxylate ions and surface charge. Values of surface charge and iodine capacity showed no relationship with the bulk densities. Maximum lead(II) adsorption was observed for the 2:1 toluene–ethanol modified sample. Lead(II) ions adsorption was inversely related to surface charge and directly related to iodine capacity.Ion-exchange was the dominating mechanism followed by chemisorption. Physical adsorption was higher in the sample modified with the 2:1 mixture which also had the least surface negative charge. Shifts in peaks of FTIR spectra indicate that unbounded –OH and acidic groups were responsible for lead(II) bonding and the contribution of these groups were different for each sample

Effect of biosynthesized silver nanoparticles on bacterial biofilm changes in S. aureus and E. coli.

One approach for solving the problem of antibiotic resistance and bacterial persistence in biofilms is treatment with metals, including silver in the form of silver nanoparticles (AgNPs). Green synthesis is an environmentally friendly method to synthesize nanoparticles with a broad spectrum of unique properties that depend on the plant extracts used. AgNPs with antibacterial and antibiofilm effects were obtained using green synthesis from plant extracts of Lagerstroemia indica (AgNPs_LI), Alstonia scholaris (AgNPs_AS), and Aglaonema multifolium (AgNPs_AM). Nanoparticles were characterized by transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX) analysis. The ability to quench free radicals and total phenolic content in solution were also evaluated. The antibacterial activity of AgNPs was studied by growth curves as well as using a diffusion test on agar medium plates to determine minimal inhibitory concentrations (MICs). The effect of AgNPs on bacterial biofilms was evaluated by crystal violet (CV) staining. Average minimum inhibitory concentrations of AgNPs_LI, AgNPs_AS, AgNPs_AM were 15 ± 5, 20 + 5, 20 + 5 μg/mL and 20 ± 5, 15 + 5, 15 + 5 μg/mL against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria, respectively. The E. coli strain formed biofilms in the presence of AgNPs, a less dense biofilm than the S. aureus strain. The highest inhibitory and destructive effect on biofilms was exhibited by AgNPs prepared using an extract from L. indica

The effects of teacher-librarianship training at the colleges of education in the former Transkei on school libraries.

Masters Degree. University of KwaZulu-Natal, Pietermaritzburg.This study investigated whether there is any significant difference between the training of teacher-librarians with the use of library facilities and the training which does not use library facilities. The study was based on the colleges of education in the former Transkei where the training of teacher­ librarians is mostly conducted with the use of very little or no library facilities. The research sample of 50% was selected from second year teacher-librarianship students who do the course as part of their teacher training at one of the colleges of education in the region mentioned above. This college was chosen on the basis that it has the best library facilities of all of them, and also that the teacher-librarianship programme offered in all these colleges is the same. A test was used as a method of gathering data. The statistical testing of the data indicated a significant difference between the two methods of instruction mentioned above, thus leading to the rejection of the null hypothesis in favour of the research hypothesis. The major conclusion drawn was that: The use of school modelled college library facilities in the training of teacher-librarians is the basic and useful tool towards the provision of functional school libraries

Surfactant-modified Macadamia nutshell for enhancement of methylene blue dye adsorption from aqueous media

This study reported the synthesis of a low-cost, and efficient adsorbent through surfactant modified macadamia nutshells (SMS) by a facile sodium dodecyl sulfonate (SDS) treatment approach. The SDS treatment resulted in increased functionalities, and ion exchangeable sites of macadamia nutshells leading to enhanced the removal of methylene blue (MB) dye from water. Factors such as pH (2-11), contact time (1-360 min), initial MB dye concentration (30-385 mg/L), and adsorbent mass (0.02 – 0.18 g/L), were tested in this study. The enhanced removal of MB removal (≥ 90%) was synergistically influenced by pH, with optimum adsorption removal around pH 7 to 11 for the SMS adsorbent. The results showed that MB removal was fast with SMS, and that the equilibrium was reached in 80 min. The batch adsorption results showed a good fit with pseudo-first-order kinetics, and the Langmuir isotherm model, in agreement with the experimental values, with a maximum adsorption capacity of 195.97 mg/g for MB. Surfactant modified macadamia nutshells (SMS) composed of surface functional groups: –OH, –C = O, -C-O, and multiple carbon-carbon bond, all contributed to synergistic mechanism interaction between the adsorbent and MB dye in this study. This study thus suggested that the SMS could be highly beneficial for eliminating anionic dye from polluted water-based solutions, thus highlighting its potential for practical usage in large pollutants removal