Brewers' spent grain in adsorption of aqueous Congo Red and malachite Green dyes: Batch and continuous flow systems.

Sorption of Congo Red (CR) and Malachite Green (MG) dyes currently used in pigments and clothing industries were investigated using brewers' spent grain (BSG) from a local brewery. Adsorption increased with a higher adsorbent weight and lower colorant concentrations. Accumulation of CR and MG was optimal at acidic pH and neutral pH respectively.

Lead exposure and blood pressure among workers in diverse industrial plants in Kenya.

The study evaluated airborne exposures and blood lead (BPb) levels in 233 production workers at six diverse industrial plants in Kenya. Blood and personal breathing zone air samples were collected and analyzed for lead (Pb) using atomic absorption spectroscopy. Blood pressure (BP) levels were measured using a standard mercury sphygmomanometer.

Adsorption of methylene blue dye from aqueous solutions using Eichhornia crassipes.

Adsorption of methylene blue (MB) from aqueous solution using dried roots, stems, and leaves of Eichhornia crassipes biomass obtained from Lake Victoria was studied. Batch experimental results revealed that the adsorption process was highly dependent on adsorbent dosage, initial MB concentration, E. crassipes particle size and aqueous solution temperature.

Air and blood lead levels in lead acid battery recycling and manufacturing plants in Kenya.

The concentration of airborne and blood lead (Pb) was assessed in a Pb acid battery recycling plant and in a Pb acid battery manufacturing plant in Kenya. In the recycling plant, full-shift area samples taken across 5 days in several production sections showed a mean value ± standard deviation (SD) of 427 ± 124 μg/m(3), while area samples in the office area had a mean ± SD of 59.2 ± 22.

High-level heterologous expression of Bacillus halodurans putative xylanase xyn11a (BH0899) in Kluyveromyces lactis.

The putative xyn11A structural gene (BH0899) encoding a family-11 xylanase from alkaliphilic Bacillus halodurans strain C-125 was heterologously expressed in the yeast Kluyveromyces lactis CBS 1065 and secreted to a level of 156 microg/ml under selective culture conditions in shake flasks. The Xyn11A production level in shake flask cultures of K. lactis CBS 1065 was higher than that reported for other xylanase genes placed under the control of the regulated LAC4 promoter on a plasmid containing an entire sequence of pKD1 from Kluyveromyces drosophilarium.

Essentiality of a newly identified carbohydrate-binding module for the function of CelB (BH0603) from the alkaliphilic bacterium Bacillus halodurans.

CelB (BH0603) from Bacillus halodurans is a modular glycoside hydrolase with a family 5 catalytic module, an immunoglobulin-like module, and module PfamB of unknown function. The recombinant PfamB module bound to Avicel and was essential for CelB hydrolytic function. We propose that module PfamB be designated a new carbohydrate-binding module.

Magnitude and direction of thermal diffusion of colloidal particles measured by thermal field-flow fractionation.

In this paper we provide experimental evidence showing that various types of submicrometer-sized particles (latexes, inorganic, and metallic), suspended in either aqueous or nonaqueous carrier liquids to which a temperature gradient dT/dx is applied, experience a force in the direction opposite to that of dT/dx. This behavior is similar to that of small particles such as soot, aerosols, and small bubbles suspended in stagnant gases across which temperature gradients are applied, a phenomenon known as "thermophoresis in gases." We report the use of a thermal field-flow fractionation (ThFFF) apparatus in two different configurations to establish the direction of particle motion subject to a temperature gradient.

Retention behavior of metal particle dispersions in aqueous and nonaqueous carriers in thermal field-flow fractionation.

Until quite recently, theories on thermophoresis of particles predicted very low thermophoretic velocities of metal particles in liquids. This prediction was based on the understanding that the very high thermal conductivities of metals relative to most liquid media resulted in quite low temperature gradients across the metal particle thereby leading to low net force on the particle. In this paper, we report the retention behavior of submicrometer size metal particles of silver (Ag), gold (Au), palladium (Pd) and platinum (Pt) suspended in both aqueous and organic (specifically, acetonitrile and tetrahydrofuran) carrier liquids in thermal field-flow fractionation (ThFFF).

Practical implications of ionic strength effects on particle retention in thermal field-flow fractionation.

Modification of ionic strength of an aqueous or non-aqueous carrier solution can have profound effects on the particle retention behavior in thermal field-flow fractionation (ThFFF). These effects can be considered as either advantageous or not depending on the performance criteria under consideration. Aside from the general increase in retention time of particulate material (latexes and silica particles), our experiments indicate improvement in resolution with increases in electrolyte concentration.

Adsorption and detection of some phenolic compounds by rice husk ash of Kenyan origin.

Rice husk ash (RHA) obtained from a rice mill in Kenya has been used as an inexpensive and effective adsorbent (and reagent) for the removal (and detection) of some phenolic compounds in water. The abundantly available rice mill waste was used in dual laboratory-scale batch experiments to evaluate its potential in: (i) the removal of phenol, 1,3-dihydroxybenzene (resorcinol) and 2-chlorophenol from water; and (ii) the detection of 1,2-dihydroxybenzene (pyrocatechol) and 1,2,3-trihydroxybenzene (pyrogallol) present in an aqueous medium. The studies were conducted using synthetic water with different initial concentrations of the phenolic compounds.

Spectrophotometric method for determination of sulfide with iron(III) and nitrilotriacetic acid by flow injection.

A manual colorimetric method for determination of sulfide has been adapted to flow injection, systematically optimized, and more fully characterized. Its intended application is for measurement of sodium sulfide reagent strength in pulp process streams, and sulfide contamination in effluent from Kraft pulp mills. In the flow-injection method developed, a sample solution containing sulfide is reacted with a mixture of iron(III) and nitrilotriacetic acid under ammoniacal conditions.

Versatile IEEE-488 data acquisition and control routines for a diode array spectrophotometer.

The UV-visible diode array spectrophotometer is a work-horse instrument for many laboratories. This article provides simple data acquisition and control routines in Microsoft QuickBasic for a HP-8452A diode array spectrophotometer interfaced to an IBM PC/XT/AT, or compatible, microcomputer. These allow capture of full spectra and measure absorbance at one or several wavelengths at preset time intervals.

Spectrophotometric determination of palladium with sulfochlorophenolazorhodanine by flow injection.

Sulfochlorophenolazorhodanine (as its sodium salt) has been used in the automated development of a sensitive flow-injection procedure for the spectrophotometric determination of palladium. The resulting method has high sample throughput, good precision, and low consumption of both sample and reagents. The optimum pH for the reaction is 5.

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.