19 research outputs found
Computer-controlled apparatus for automated development of continuous flow methods
An automated apparatus to assist in the development of analytical
continuous flow methods is described. The system is capable of
controlling and monitoring a variety of pumps, valves, and
detectors through an IBM PC-AT compatible computer. System
components consist of two types of peristaltic pumps (including a
multiple pump unit), syringe pumps, electrically and pneumatically
actuated valves, and an assortment of spectrophotometric and
electrochemical detectors. Details of the interface circuitry are given
where appropriate. To demonstrate the utility of the system, an
automatically generated response surface is presented for the flow
injection determination of iron(II) by its reaction with
1,10-phenanthroline
Removal of heavy-metals from wastewater using a hydrous alumino-silicate mineral from Kenya
Heavy metalsâ discharge into the environment continues to pose grave concerns around the world. The efficacy of a hydrous alumino-silicate clay (AlSiM) coming obtained from some regions of Kenya to sorb heavy-metal ions from water has been evaluated in batch tests taking into account changes in adsorbent dose, pH, contact time, and temperature. Complete metal removals, from water containing up to 66 mg/L of Pb(II) was achieved using this material at pH value of 5 over a temperature range of 289â333 K. The adsorption data fitted both the Langmuir and the Dubinin-Radushkevich isotherms with R2 > 0.99. The D-R adsorption energy (â11.7 kJ/mol) indicated that chemisorption was the primary reaction in the adsorption process and the derived âG0 value (â7.45 kJ/mol) was consistent with the spontaneity of the adsorption process. The kinetic analyses indicated a film-diffusion and surface-chemisorption controlled process. Verification of the initial results on heavy metals-containing wastewaters obtained from a tannery and a leather processing industries revealed excellent adsorption efficacies of AlSiM for Cr3+ (99â100%), Fe3+ (96â98%), Mn2+ (85â97%) and Zn2+ (78â86%). The use of AlSiM as a plausible low-cost adsorbent for heavy-metal decontamination of industrial effluents has therefore been demonstrated
Experimental Evidence of Thermophoresis of Non-Brownian Particles in Pure Liquids and Estimation of Their Thermophoretic Mobility
Quality and psychosocial factors influencing purchase of orangeâfleshed sweet potato bread
This 2018 study, conducted in six Tusky's supermarkets in Nairobi, Kenya, combined the JustâAboutâRight, Penalty and MeanâEndâChain analyses to examine the quality and psychosocial factors influencing the purchase of a novel bread made from orangeâfleshed sweet potato (OFSP), a biofortified crop, focusing on sixtyâone male and eighty female urban OFSP bread buyers recruited at point of purchase. It finds that sensory and psychosocial factors drive purchasing decisions and that some of the bread's sensory characteristics are misaligned with consumers' expectations. It also finds that women and menâs evaluations of the bread's characteristics are different, as are their motivations for purchase. However, good sensory attributes and the knowledge of the bread's nutritional value were key drivers. Some misaligned characteristics reveal levers for the reformulation of the bread and present opportunities for segmenting the market. Several other implications of the findings for policy and future improvement of the bread are discussed