Bio

PDF Upload: 

Publications


Submitted

Shiundu, PM, Munguti SM, Williams KRS.  Submitted.  Practical implications of ionic strength effects on particle retention in thermal field-flow fractionation. AbstractPractical 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. Absence of an electrolyte in the carrier solution causes deviations from the theoretically expected linear behavior between the retention parameter l (a measure of the extent of interaction between the applied field and the particle) and the reciprocal temperature drop across the channel walls. A negative interaction parameter d of about 20.170 was determined for 0.105- and 0.220-mm polystyrene (PS) latex particles suspended in either a 0.25 or a 1.0 mM TBAPcontaining acetonitrile carrier and for 0.220 mm PS in 0.50 and 1.0 mM NaCl-containing aqueous medium. This work also demonstrates that optimum electrolyte concentrations can be chosen to achieve reasonable experimental run-times, good resolution separations, and shifts in the steric inversion points at lower field strengths, and that too high electrolyte concentrations can have deleterious effects such as band broadening and sample loss through adsorption to the channel accumulation surface. The advantages of using ionic strength rather than field strength to effect desired changes are lowered power consumption and possible application of ThFFF to high temperature-labile samples.

M, PROFSHIUNDUPAUL.  Submitted.  Wilson G. Kamundia, Paul M. Shiundu, and John M. Onyari, . Federation of Analytical Chemistry and Spectroscopy Society (FACSS) XV, Boston, November 1988. : AWC and FES Abstract
n/a
M, PROFSHIUNDUPAUL.  Submitted.  Patrick M. Shem, Paul M. Shiundu, Nicholas K. Gikonyo, Ahmed Hasssanali and Rajinder K. Saini, . Federation of Analytical Chemistry and Spectroscopy Society (FACSS) XV, Boston, November 1988. : AWC and FES Abstract
n/a
M, PROFSHIUNDUPAUL.  Submitted.  Patrick M. Shem, Paul M. Shiundu, Nicholas K. Gikonyo, Ahmed Hasssanali and Rajinder K. Saini, . Federation of Analytical Chemistry and Spectroscopy Society (FACSS) XV, Boston, November 1988. : AWC and FES Abstract
n/a
M, PROFSHIUNDUPAUL.  Submitted.  Wilson G. Kamundia, Paul M. Shiundu, and John M. Onyari, . Federation of Analytical Chemistry and Spectroscopy Society (FACSS) XV, Boston, November 1988. : AWC and FES Abstract
n/a

2019

Wanyonyi, WC, Onyari JM, Shiundu PM, Mulaa FJ.  2019.  Effective biotransformation of Reactive Black 5 Dye Using Crude Protease from Bacillus Cereus Strain KM201428. Energy Procedia. 157:815-824. AbstractEnergy Procedia

Description

Effective effluent treatment is a paramount step towards conserving the dwindling clean water resources. The present study describes the use of crude protease extract from Bacillus Cereus Strain KM201428 biotransformation of azo dye Reactive Black 5 (RB5). Batch experimental results displayed over 97% decolorization efficiency with initial dye concentration of 1.0 x 10-4M. The decolorization process was highly dependent on contact time, dye concentration and pH. The optimum contact time and pH for decolorization were 120 hours and pH 9 respectively at 25˚C. Biotransformation of RB5 dye was monitored using UV-Vis spectrophotometer and formed metabolites characterized by LC–QTOF-MS. Comparison of resultant LC–QTOF-MS chromatograms after decolorization confirmed complete cleavage of RB5 dye. First order kinetic fitted well with experimental data for different RB5 dye concentrations …

Chanzu, HA, Onyari JM, Shiundu PM.  2019.  Brewers’ spent grain in adsorption of aqueous Congo Red and malachite Green dyes: Batch and continuous flow systems. Journal of hazardous materials. 380:120897. AbstractJournal article

Description

Abstract 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. Sorption decreased with an increase in temperature signifying an exothermic process. Batch adsorption data fitted better to Langmuir adsorption isotherm model and pseudo-second-order kinetics. Maximum monolayer coverage capacities (Q O)) were found to be 2.55 mg/g for MG and 36.5 mg/g for CR dye. Column studies using BSG were also conducted for both dyes. Fixed bed breakthrough was fast with an increase in dye concentration, adsorbent surface area, and flow rate and with a decrease in column depth. BSG are effective, simple in design …

2018

Wambu, EW, Attahiru S, Shiundu PM, wabomba J.  2018.  Removal of heavy-metals from wastewater using a hydrous alumino-silicate mineral from Kenya. Bulletin of the Chemical Society of Ethiopia. 32(1):39-51. AbstractAJOL Journal

Description

Heavy metals’ 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 289–333 K. The adsorption data fitted both the Langmuir and the Dubinin-Radushkevich isotherms with R 2> 0.99. The DR adsorption energy (− 11.7 kJ/mol) indicated that chemisorption was the primary reaction in the adsorption process and the derived∆ G 0 value (− 7.45 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 Cr 3+(99− 100%), Fe 3+(96− 98%), Mn 2+(85− 97%) and Zn 2+(78− 86%). The use of AlSiM as a plausible low-cost adsorbent for heavy-metal decontamination of industrial effluents has therefore been demonstrated.

Masenge, EM, Wandiga SO, Shiundu PM, Madadi VO.  2018.  Analysis of Total Petroleum Hydrocarbons in Water from Ngong and Mathare Rivers, Nairobi County, Kenya. IJSRSET. 4(8):252-256. Abstract

Description

Unsustainable industrial development has created negative impacts to global ecosystem quality and biodiversity due to increased load of chemical and biological contaminants released into environment. Ecological sustainability of Nairobi River Basin in Kenya, hangs in the balance between socioeconomic exploitation and environmental management. Nairobi, Ngong and Mathare rivers constitute the three main tributaries of Nairobi River Basin. The basin has witnesssed increased pollution load, destruction of the wetlands and encroachment of the buffer zones due to rapid urbanisation. The objective of this study was to investigate the extent of total petroleum hydrocarbons (TPH) contamination in Mathare and Ngong rivers. We collected water from eight sampling sites constituting the upstream, midstream and downstream of the two rivers. The samples were extracted using HPLC grade dichloromathane and analysed for Total Petroleum Hydrocarbons (TPH) using a Gas Chromatography equipped with Flame Ionisation Detector. TPH in Mathare River ranged from 59.66±8.64 to 463.92±2.63 µg/L, whereas levels in Ngong’River ranged from 11.85±0.10 to 1,219.95 µg/L. The concentration increased downstream indicating the influence of industrial and urbanistion on the pollution load. The results suggest that industries and municipal activities in the City are contributing to TPH contamination in the Nairobi River Basin tributaries and therefore they are likely to jeopardize ecological quality of the rivers ecosystems if protective measures are not taken.

2017

Wabomba, JN, Shiundu PM, Onyari JM, Yanful E.  2017.  Equilibrium and Kinetic Studies of Cu (Ii) Removal from Aqueous Solutions Using a Kenyan Micaceous Mineral.. International Journal of Innovation Education and Research. 5(4):181-198. AbstractInternational Journal of Innovation Education and Research

Description
Copper (II) sorption on a Kenyan micaceous mineral (Mica-K) was studied in the batch mode. The effects of different experimental parameters such as; initial concentration, contact time, sorbent dose, pH, particle size, agitation speed, competition and temperature on the kinetics of copper removal were studied. The sorption pattern of copper onto Mica-K followed Langmuir and Freundlich isotherms. Thermodynamic parameters for copper sorption on Mica-K were also determined. X-ray photoelectron spectroscopic (XPS) analysis of metal ion-equilibrated Mica-K, demonstrated that copper, cadmium and Zinc containing nodules existed on the surface of Mica-K.

Wanyonyi, WC, Onyari JM, Shiundu PM, Mulaa FJ.  2017.  Biodegradation and detoxification of malachite green dye using novel enzymes from bacillus cereus strain KM201428: kinetic and metabolite analysis. Energy Procedia. 119:38-51. AbstractScience Direct Journal

Description
Enzyme based degradation of organic pollutants is a promising detoxifying approach due to the promiscuous nature of the enzyme, efficiency, cost effective and ecofriendly. In the present study, we have carried out detailed decoloration and degradation studies on a model triphenyl methane group of dyes (Malachite Green dye (MG)) using a newly isolated enzyme from Bacillus cereus KM201428 under the static condition. Biodegradation of dyes was monitored by UV-VIS spectrophotometer and the resultant metabolites analyzed by Liquid Chromatography–Hybrid Quadrupole Time of Flight Mass Spectrometry (LC–QToF-MS) and Gas Chromatography/Mass Spectrometry (GC - MS). Metabolite analysis results revealed that enzymatic degradation of MG dye resulted in complete mineralization and benzene ring-removal; the latter known for organic dye toxicity. Kinetic study results revealed that first-order kinetic …

2013

2012

2010

  2010.  Introductory Chemistry 1. AbstractIntroductory Chemistry 1

This module covers introductory topics that are fundamental to understanding the subject of chemistry. In this module, we shall examine the structure of the smallest part of an element known as the atom (the building blocks of matter) and associated atomic models. The focus will be on the thought process involved in the development of the periodic table and its use in explaining the structure and properties of elements in “groups” and “periods”. Both microscopic (in which matter is regarded as a collection of atoms and molecules) and macroscopic (associated with the bulk properties of matter) views of matter will be considered. The underlying principles that govern structures and shapes of simple molecules and ions will be covered as well as the nomenclature for writing formula for binary inorganic compounds, cations and anions. In addition, a review of the concepts behinds interpretation and balancing of chemical equations, stoichiometric calculations involving quantitative relations in chemical reactions, calculations of percent composition by mass and derivation of molecular formula from experimental data will also be made.

2009

Kim, S, Williams R, Cinque L, Shiundu PM.  2009.  Size Determination of Nanoparticles Used in Coatings. AbstractSize Determination of Nanoparticles Used in Coatings

This chapter begins with a description of some commonly used particle sizing techniques, their applicability to nanoparticles, and their advantages and disadvantages. A special emphasis is given to fractionation techniques and their ability to simultaneously characterize nanoparticles and isolate monodispersed fractions from polydispersed samples. The latter part of this chapter provides an in-depth discussion of sedimentation field-flow fractionation (SdFFF) size analysis of nanoparticles used in coatings

2007

Kremmer, E, Krämer PM, Weber CM, Räuber C, Martens D, Forster S, Stanker LH, Rauch P, Shiundu PM, Mulaa FJ.  2007.  Optical Immunosensor and ELISA for the Analysis of Pyrethroids and DDT in Environmental Samples. AbstractOptical Immunosensor and ELISA for the Analysis of Pyrethroids and DDT in Environmental Samples

An optical immunosensor (AQUA-OPTOSENSOR) and ELISA (enzyme-linked immunosorbent assay) for the analysis of pyrethroids and DDT in river water and/or sediment, are described. The optical immunosensor consists of a bench-top optical read-out-device and disposable single-use sensor chips. ELISA was carried out in the coating antigen format. As examples, phenothrin (pyrethroid) and p,p'-DDT were chosen. Herein we describe the overall strategy, the set-up and principle of the immunosensor platform, and show representative results for immunosensor and ELISA analysis. The immunosensor employs fluorophore (Oyster®-645)-labeled monoclonal antibodies (mouse mAb Py-1 and rat mAb DDT 7C12), and makes use of the evanescent field, thus operating without washing steps. ELISA in the coating antigen format uses a second antibody labeled with peroxidase. Both, phenothrin and p,p'-DDT can be analyzed with these immunochemical techniques in the low ppb levels. Advantages and drawbacks of both immunochemical platforms are discussed.

2006

M, PROFSHIUNDUPAUL.  2006.  Benson Munyali Wamalwa; Makiko Sakka; Paul Mwanza Shiundu; Kunio Ohmiya; Tetsuya Kimura; and Kazuo Sakka, . Appl. Environ. Microbiol., 72 (10), 6851-6853. : AWC and FES Abstract
Five plasters and one fiberglass casting bandages available on the Kenyan market were evaluated for breaking strength and resistance to abrasion. Under the test conditions, scotch cast was found to be 2.6 times stronger than the strongest plaster of Paris preparation when the load per unit thickness was compared and was significantly different from the plaster casts in terms of maximum load (p=0.0001). Among the plaster products, there were significant statistical differences (p=0.029) in maximum strength with Helm and Plasrum-gyps withstanding the greatest load. Scotchcast was the most resistant to abrasion while among the plaster product, Salvaplast and POP-Nairobi Enterprises showed satisfactory resistance Heal, Plasrun-gyps and Veronese proved least resistant under the testing conditions.

2005

M, PROFSHIUNDUPAUL.  2005.  Wamalwa, B.M., M. Sakka, P.M. Shiundu, T. Kimura, K. Ohmiya, and K. Sakka, . J. Appl. Glycoscience, 52 Suppl., 49-51. : AWC and FES Abstract
domain of the putative celB gene from alkalophilic Bacillus

2003

M, PROFSHIUNDUPAUL.  2003.  Removal of Cu (II) from an aqueous solution using a micaceous mineral of Kenyan origin, Adsorption Science Technology , 21 (3), 269-283. J. Colloid and Interface Sci., 266(2), 366-376. : AWC and FES Abstract
domain of the putative celB gene from alkalophilic Bacillus
M, PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL.  2003.  Retention Behavior of Metal Particle Dispersions in Aqueous and Nonaqueous Carriers in Thermal Field-Flow Fractionation. J. Chromatogr. A., 983, 163-176. : AWC and FES Abstract
domain of the putative celB gene from alkalophilic Bacillus
M, PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL.  2003.  Magnitude and Direction of Thermal Diffusion of Colloidal Particles Measured by Thermal Field-Flow Fractionation. J. Colloid and Interface Sci., 266(2), 366-376. : AWC and FES Abstract
domain of the putative celB gene from alkalophilic Bacillus

2002

M, PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL.  2002.  Sorption and Detection of Phenolic Compounds by Rice Husk Ash of Kenyan Origin. J. Environ. Monit., 4,978-984. : AWC and FES Abstract
n/a
M, PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL.  2002.  Thermal Field-Flow Fractionation for Particle Analysis: Opportunities and Challenges. Polym. Mater. Sci. Eng., 87, 342. : AWC and FES Abstract
n/a
M, PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL.  2002.  Factors Affecting Particle Retention in Thermal Field-Flow Fractionation. Bull. Chem. Soc. Ethiop., 16(1),91-101. : AWC and FES Abstract
domain of the putative celB gene from alkalophilic Bacillus

2000

M, PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL.  2000.  Thermal Stability Studies on Vernonia Galamensis Seed Oil. Bull. Chem. Soc. Ethiop., 14(2), 161-167. : AWC and FES Abstract
n/a

1998

N, PROFKAMAUGEOFREY, M PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL.  1998.  Fuel value of Refined vernonia galamensis seed oil". J. Biochemphysics, 6&7, 33.. : AWC and FES Abstract
n/a

1996

M, PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL.  1996.  Field-Flow Fractionation: Theory and Practice. Proceedings of the 2nd Theoretical Chemistry Workshop in Africa held on 26th-30th August, 1996, Nairobi, Kenya.. : AWC and FES Abstract
n/a
M, PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL.  1996.  Isolation and Characterization of Polymeric and Particulates of Acrylonitrile-Butadiene-Styrene (ABS) Plastics by Thermal FFF.. J. Appl. Polym. Science., 60, 1695-1707. : AWC and FES Abstract
n/a

1995

M, PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL.  1995.  Size and Composition Studies of Core-Shell Latexes Using Flow and Thermal Field-Flow Fractionation. Colloids Surfaces A: Physicochemical and Engineering Aspects., 105, 243-250,. : AWC and FES Abstract
n/a
M, PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL.  1995.  Thermophoresis of Metal Particles in a Liquid.", J. Colloid and Interface Science, 176, 454-458,. : AWC and FES Abstract
n/a
M, PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL.  1995.  Influence of Bulk and Surface Composition on the Retention of Colloidal Particles in Thermal Field-Flow Fractionation.. J.Chromatography A., 715, 117-126. : AWC and FES Abstract
n/a
M, PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL.  1995.  Separation of Particles in Nonaqueous Suspensions by Thermal Field-Flow Fractionation. Anal. Chem., 67, 2705-2713,. : AWC and FES Abstract
n/a

1994

1992

M, PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL.  1992.  Spectrophotometric Method for Determination of Sulfide with Iron(III) and Nitrilotriacetic Acid by Flow Injection. Talanta, 39(3), 299-312. : AWC and FES Abstract
n/a

1991

M, PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL.  1991.  Development of Catalytic Photometric Flow Injection Methods for Determination of Selenium. Anal. Chem., 63, 692-699,. : AWC and FES Abstract
n/a
M, PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL.  1991.  Versatile IEEE-488 Data Acquisition and Control Routines for Diode Array Spectrophotometer. J. Automatic Chem., 13(3), 83-92,. : AWC and FES Abstract
n/a

1990

M, PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL.  1990.  "Automated Exploration and Exploitation of Flow Injection Response Surfaces. Anal.Chim.Acta, 237, 361-379. : AWC and FES Abstract
n/a

UoN Websites Search