Jackson Kiptoo - Academia.edu (original) (raw)

Papers by Jackson Kiptoo

Scientific Reports

The paucity of safe drinking water remains a global concern. Fluoride is a pollutant prevalent in... more The paucity of safe drinking water remains a global concern. Fluoride is a pollutant prevalent in groundwater that has adverse health effects. To resolve this concern, we devised a silica-based defluoridation sorbent from pumice rock obtained from the Paka volcano in Baringo County, Kenya. The alkaline leaching technique was used to extract silica particles from pumice rock, which were subsequently modified with iron to enhance their affinity for fluoride. To assess its efficacy, selected borehole water samples were used. Scanning electron microscopy, X-ray diffraction, Fourier transform infrared and X-ray fluorescence spectroscopy was used to characterize the sorbent. The extracted silica particles were 96.71% pure and amorphous, whereas the iron-functionalized silica particles contained 93.67% SiO2 and 2.93% Fe2O3. The optimal pH, sorbent dose and contact time for defluoridation of a 20 mg/L initial fluoride solution were 6, 1 g and 45 min, respectively. Defluoridation followed ps...

International Journal of Multidisciplinary Research and Development, 2016

Over 1.1 billion people in the world lack access to portable water. Diarrheal and other waterborn... more Over 1.1 billion people in the world lack access to portable water. Diarrheal and other waterborne diseases cause an estimated 2.2 million deaths per year. Chlorination is a proven water treatment method for municipal water. Concerns have been raised about the potential long term health effects of disinfection by-products to users of chlorinated water. This study investigated the production of trihalomethanes (THMs) and Haloacetic acids (HAAs) in chlorinated tap water from Nairobi City, Kenya. The study was done using Gas Chromatography-Electron Capture (GC-ECD). Tap water samples were collected from ten locations around the city for analysis of THMs and HAAs. The study also investigated the effects of pH, Temperature, Colour, Turbidity, Ultra Violet Absorption and organic carbon. Data obtained was subjected to Microsoft Excel and analysis of variance (ANOVA). Some samples showed significant amount of Chloroforrm:ranging between 7.4μg/L and 13.06μg/L. Other samples showed traces of ...

Chemical Science International Journal

The presence of pharmaceutical residues in discharges that end up in rivers is a growing concern ... more The presence of pharmaceutical residues in discharges that end up in rivers is a growing concern for the disruption of aquatic ecosystems and human health. The risk of exposure to these medical wastes becomes greater because they are not biodegradable even after sewage treatment. This study aimed to remove trimethoprim (antibiotic), paracetamol (painkiller), and nevirapine (anti-retroviral) from wastewater using activated carbon made from rice husks, an agricultural waste that was investigated as a potential adsorbent. The instrument used for analysis was a liquid chromatography-tandem mass spectrometer (LC-MS/MS). The powdered carbon of rice husks was carbonated at a temperature of 500oC and then activated by phosphoric acid to increase its porosity. After activation, it was successfully characterized by the use of Scanning electron microscopy which showed irregular cavities with open fine pores. Fourier transform infrared showed different functional groups which determined adsorbe...

International journal of advanced research, May 21, 2022

Synthesis and characterization of hexamine capped ZnSeO4 QDs (ZnSeO4-Hex) by heating up method (H... more Synthesis and characterization of hexamine capped ZnSeO4 QDs (ZnSeO4-Hex) by heating up method (HU) was achieved. These, of two crystallite sizes, denoted QDsS1 and QDsS2; with crystallite diameters of 8.6 nm and 14.0 nm respectively. X-ray diffraction (XRD) pattern bared hexagonal close packed (hcp) crystal structure. Band gap for QDsS1 was 5.85 eV and for QDsS2 3.8 to 4.3 eV. Hexamine (C6H10N4) cap on ZnSeO4 QDs was elucidated by Fourier Transform Infrared Spectroscopy (FTIR) and Gas Chromatography-Mass Spectroscopy (GC-MS) results. Transmission Electron Microscopy (TEM) images revealed polycrystallites of different orientation, showing crystal grains separated by tilted grain boundary folds. These QDs were tested as optical chemical nano-sensors for carcinogenic organic pollutants: Anthracene (ANTH), Benzo (a) pyrene (BaP), pyrene (PRN) and pyridine (py). Results revealed that, when the organic pollutants interacted with the QDs, they caused characteristic changes in the way these nanoparticles interacted with characteristic fluorescence and absorbance spectrum.

In this paper, the influence of contact time, initial pH and metal ion concentrations on the adso... more In this paper, the influence of contact time, initial pH and metal ion concentrations on the adsorption properties of a freshwater green alga (Spirogyra sp.) biomass was studied. Several model solutions of selected heavy metals (Cd, Cu, Cr, Pb) were put into contact with the green algae-based sorbent for different time periods. After the treatment, the concentrations of heavy metals in model solutions were determined using flame atomic absorption spectrometry (FAAS) and inductively-coupled plasmaoptical emission spectrometry (ICP-OES). Fourier transform infrared spectroscopy (FTIR) was used to reveal which functional groups were responsible for the green algae biosorption properties. Adsorption capacities were found to be 22.52, 38.19, 35.59 and 94.34 mg/g for Cd, Cr, Cu and Pb, respectively, at contact times of 15-50 minutes and initial metal ion concentrations of 500-700 µg/g. The optimum pH for biosorption of Cd, Cr, Cu and Pb were 5.5, 5.8, 5.9 and 5.0, respectively. The biosorption process followed second order kinetics and fittedthe Langmuir isotherm model. Biomonitoring studies suggested the possible use of this freshwater green algaas a bioindicator, with mean concentration factors for the selected elements in the range of 367-7154.

Journal of Agricultural Science and Technology, 2016

The international Convention on the Elimination of Persistent Organic Pollutants (POPs) lists med... more The international Convention on the Elimination of Persistent Organic Pollutants (POPs) lists medical waste incinerators among the main dioxin and furans sources in the environment. However, medical waste incinerators emit a wide range of pollutants besides dioxins and furans. These include heavy metals (lead, mercury and cadmium), fine dust particles, hydrogen chloride, sulphur dioxide, carbon monoxide, nitrogen oxides and other pollutants such as Products of Incomplete Combustion (PICs) into the atmosphere. The composition of health care waste generated can guide decisions on what disposal method is required for a particular health care facility. The purpose of this study was to evaluate health care waste management practices and compliance to the burn technology among the selected hospitals in Kiambu County, Kenya. Questionnaires were used for collecting information from respondents; analysis of heavy metal contaminants was done to ascertain the composition of the health care was...

Chemical Science International Journal, 2019

Agricultural activities, discharge of raw sewage into farms and the rise in urbanization have gre... more Agricultural activities, discharge of raw sewage into farms and the rise in urbanization have greatly contributed to soil pollution. During the rainy season, surface runoff from farms find their way into water bodies and deposits these contaminants into Rivers and Lakes which poses a threat to both aquatic and terrestrial organisms that depend on that water source. The objective of this research was to determine the level of anions and heavy metals from sediments in River Sio, Busia County, Kenya. Five sediment samples were taken from five sampling points and the levels of anions and heavy metals in them determined. Anions were determined using Shimadzu 1800 UV/visible spectrophotometer while heavy metals were determined using Shimadzu 6200 flame atomic absorption spectrophotometer (AAS). Copper, lead and nickel were above the allowed WHO limits while cadmium was below detection limit. The levels of nitrates, phosphates and chlorides were higher during the wet season due to surface ...

Journal of Agricultural Science and Technology, Apr 6, 2014

Chemical Science International Journal, 2020

Open dumpsites are one of the main sources of heavy metals and as a result, lots of research has ... more Open dumpsites are one of the main sources of heavy metals and as a result, lots of research has been undertaken on the pseudo-total content of heavy metals in dumpsite soils, but little research on the forms in which they exist. The current research was carried out to determine levels of chromium, lead and cadmium in the various fractions of Dandora dumpsite soil and how they are fractionated in the topsoil and subsoil horizons. Samples were obtained from eight sites with depths of (0-30 cm) and (30-60 cm) for topsoil and bottom soils respectively. The modified Community Bureau of Reference (BCR) sequential extraction procedure was used and metal analysis performed using flame atomic absorption spectrophotometry. The metals (lead, chromium and cadmium) total concentration (µg/g) in the upper soil profile ranged from 42.22 to 1096.21, 38.26 to 180.60 and 11.23 to 44.22 while the lower soil profiles were 54.19 to 239.28, 30.56 to 76.48 and 9.47 to 22.56, respectively. The concentrati...

Journal of environment and earth science, 2016

Effect of effluents into rivers is of great economic, environmental and health concern. Chemical ... more Effect of effluents into rivers is of great economic, environmental and health concern. Chemical fertilizers are used extensively in modern agriculture, in order to improve yield and productivity of agricultural products. However, nutrients, leaching through the soil from agricultural activities, sewerage effluents and runoff from residential areas reaching river water resources are causing serious pollution. The purpose of this study was to determine the impact of effluent discharges on water quality of River Mathioya in Murang’a County, Kenya. Samples were collected upstream and downstream of Murang’a town along the Mathioya River. The pH, dissolved oxygen, electrical conductivity, total dissolved solid, total suspended solids and temperature were determined using the respective meters. Heavy metals were determined using flame atomic absorption spectrometry while sodium and potassium were determined using flame photometry. Nitrates and phosphates were determined using UV/Visible s...

Bulletin of the Chemical Society of Ethiopia, 2005

This paper reports results on complex formation reactions between OH^-, Cl&... more This paper reports results on complex formation reactions between OH^-, Cl^-, EDTA and carbohydrate ligands with Pb²⁺ ions at various [L_T]:[M_T] ratios and at different pH values (1.5-13.0). Differential pulse anodic stripping voltammetry (DPASV) employing an <i>ex situ</i> plated thin mercury film electrode (TMFE) was used to measure the shifts in peak potentials. Formation of simple, polyligand as well as mixed ligand complexes are reported. The reactions between the Pb(II) and the carbohydrate ligands showed pronounced pH dependency on metal forms compared to reactions with simple inorganic ions such as chloride. Modeling of the experimental data obtained with the DPASV method was done using computer software (3D-VISE). The calculated complex formation curves (CCFC) based on mass balance equations were fitted to the experimental complex formation curves (ECF...

The drive for targeting higher agricultural production needs a balanced use of nutrients which ot... more The drive for targeting higher agricultural production needs a balanced use of nutrients which otherwise create problems of soil fertility exhaustion and nutrient imbalances. The current research sampled 15 farms from Ololulunga, Narok County to determine the levels of nitrate, phosphate and sulfate using UV-VIS and data analyzed using MSTAT-C, SPSS and student ttest. The nitrate concentration varied from 32.441mg/kg to 11.108mg/kg before planting and 36.759mg/kg to 21.646mg/kg after planting. The phosphate concentration varied from 3.001mg/kg to 0.368mg/kg before planting and 9.508 mg/kg to 2.357mg/kg after planting. The sulfates concentration varied from 6.678mg/kg to 3.661mg/kg before planting and 8.028 mg/kg to 4.111 mg/kg after planting. Generally, it was observed that almost all farms had different application rates of these nutrients and maybe this depended on the financial ability of individual farmer. It was found that nitrate had the least CV% of 6.71, sulfates, 8.54% and ...

Chemical Science International Journal, 2019

Environmental pollution by heavy metals is presently a serious threat to public health. Despite t... more Environmental pollution by heavy metals is presently a serious threat to public health. Despite the toxic contaminants contained in municipal waste, most of the dumpsites remain unregulated and uncontrolled. The objective of this study was to determine the levels of Pb, Cr and Cd in the leaves of tobacco tree plants growing around the dumpsite so as to assess their impact on the environment. The pseudo-total concentration of the metals in the soil was done so as to calculate the transfer factors.pH and total organic carbon (TOC) of the soil was also determined. Soil and plant samples were collected thrice from thirty two sampling sites along the off-loading path from the centre of Dandora dumpsite up to a distance of 700 m away from the centre at depth of 0-30cm (top soil). Metal analysis was done using flame atomic absorption spectroscopy (FAAS). Pb levels ranged from 7.58±0.34 to 16.57±0.79 µg/g in the washed leaves and 9.22±0.36 to 19.27±0.40 µg/g in the unwashed leaves. Cr leve...

International Research Journal of Pure and Applied Chemistry, 2019

Water samples were taken from five sampling points and their quality assessed through analysis of... more Water samples were taken from five sampling points and their quality assessed through analysis of physical and chemical characteristics. Turbidity, temperature, conductivity, pH, dissolved oxygen and total suspended solids were determined on site during sample collection, using potable meters. Anions were determined using UV/Visible spectroscopy while heavy metals were determined using flame Atomic Absorption Spectroscopy (AAS) in accordance with AWWA standard methods. Turbidity was the highest recorded parameter during the wet season with a mean of 481.83 NTU. 53% of the parameters showed significant seasonal variation (P<0.5) with the mean concentration of 56 % of the parameters being higher during the wet season. The parameters that exceeded the WHO limit were turbidity, phosphates, lead, iron, nickel, chromium and cobalt indicating poor quality of water in River Sio. Poor agricultural practices, domestic and industrial wastewater are the main factors that contribute to pollut...

Journal of environment and earth science, 2015

This study sampled wheat farms in Ntulele area of Narok county to determine the levels of nitrate... more This study sampled wheat farms in Ntulele area of Narok county to determine the levels of nitrate, phosphate and sulfate using UV-VIS spectrophotometer and data analyzed using MSTAT-C, SPSS and student t-test. Nitrates were found to be sufficient whereas phosphates and sulfates were found to be deficient in most of the farms sampled. Sulfate had the least CV% of 8.54 followed by nitrates with 14.23% and phosphate had the highest with 21.91% an indication that all the nutrients were applied in similar rates by the farmers of Ntulele. The nutrients before and after planting were significant (p<0.05). Keywords: Nitrate, Sulfate, Phosphate, UV-VIS, Soil, Ntulele

In this paper, adsorption features of freshwater green algae as a function of contact time, initi... more In this paper, adsorption features of freshwater green algae as a function of contact time, initial pH and initial metal ion concentrations were studied using model solutions of metal ions with subsequent determination by flame atomic absorption spectrometry (FAAS). Green algae samples were employed as bioindicators of selected heavy metals in environmental water samples with determination using FAAS and ICP-OES (inductively-coupled plasma-optical emission spectrometry). The optimum pH for cadmium (Cd), chromium (Cr), copper (Cu) and lead (Pb) biosorption were found to be 5.5, 5.8, 5.9 and 5.0, respectively. The biosorption process follows second order kinetics and is well described by the Langmuir isotherm model. Adsorption capacities were found to be 22.52, 38.19, 35.59 and 94.34 mg/g for Cd, Cr, Cu and Pb, respectively, at contact times of 15-50 minutes and initial metal ion concentrations of 500-700 mg/L. Biomonitoring studies revealed great potential for freshwater green algae ...

Results of speciation studies of nickel and chromium in wastewater, surface and groundwater syste... more Results of speciation studies of nickel and chromium in wastewater, surface and groundwater systems using flame atomic absorption spectrometry (FAAS), graphite furnace atomic absorption spectrometry (GFAAS) and differential pulse adsorptive cathodic stripping voltammetry (DPAdCSV) are presented. Dimethylglyoxime (DMG) and diethylenetriaminepentaacetic acid (DTPA) were used as complexing agents for DPAdCSV determination of nickel and chromium, respectively, at a hanging mercury drop electrode (HMDE). Total nickel was in the range 3091–3201 mg L –1 in wastewater from an electroplating plant, 8.1–14.4 µg L –1

Scientific Reports

The paucity of safe drinking water remains a global concern. Fluoride is a pollutant prevalent in... more The paucity of safe drinking water remains a global concern. Fluoride is a pollutant prevalent in groundwater that has adverse health effects. To resolve this concern, we devised a silica-based defluoridation sorbent from pumice rock obtained from the Paka volcano in Baringo County, Kenya. The alkaline leaching technique was used to extract silica particles from pumice rock, which were subsequently modified with iron to enhance their affinity for fluoride. To assess its efficacy, selected borehole water samples were used. Scanning electron microscopy, X-ray diffraction, Fourier transform infrared and X-ray fluorescence spectroscopy was used to characterize the sorbent. The extracted silica particles were 96.71% pure and amorphous, whereas the iron-functionalized silica particles contained 93.67% SiO2 and 2.93% Fe2O3. The optimal pH, sorbent dose and contact time for defluoridation of a 20 mg/L initial fluoride solution were 6, 1 g and 45 min, respectively. Defluoridation followed ps...

International Journal of Multidisciplinary Research and Development, 2016

Over 1.1 billion people in the world lack access to portable water. Diarrheal and other waterborn... more Over 1.1 billion people in the world lack access to portable water. Diarrheal and other waterborne diseases cause an estimated 2.2 million deaths per year. Chlorination is a proven water treatment method for municipal water. Concerns have been raised about the potential long term health effects of disinfection by-products to users of chlorinated water. This study investigated the production of trihalomethanes (THMs) and Haloacetic acids (HAAs) in chlorinated tap water from Nairobi City, Kenya. The study was done using Gas Chromatography-Electron Capture (GC-ECD). Tap water samples were collected from ten locations around the city for analysis of THMs and HAAs. The study also investigated the effects of pH, Temperature, Colour, Turbidity, Ultra Violet Absorption and organic carbon. Data obtained was subjected to Microsoft Excel and analysis of variance (ANOVA). Some samples showed significant amount of Chloroforrm:ranging between 7.4μg/L and 13.06μg/L. Other samples showed traces of ...

Chemical Science International Journal

The presence of pharmaceutical residues in discharges that end up in rivers is a growing concern ... more The presence of pharmaceutical residues in discharges that end up in rivers is a growing concern for the disruption of aquatic ecosystems and human health. The risk of exposure to these medical wastes becomes greater because they are not biodegradable even after sewage treatment. This study aimed to remove trimethoprim (antibiotic), paracetamol (painkiller), and nevirapine (anti-retroviral) from wastewater using activated carbon made from rice husks, an agricultural waste that was investigated as a potential adsorbent. The instrument used for analysis was a liquid chromatography-tandem mass spectrometer (LC-MS/MS). The powdered carbon of rice husks was carbonated at a temperature of 500oC and then activated by phosphoric acid to increase its porosity. After activation, it was successfully characterized by the use of Scanning electron microscopy which showed irregular cavities with open fine pores. Fourier transform infrared showed different functional groups which determined adsorbe...

International journal of advanced research, May 21, 2022

Synthesis and characterization of hexamine capped ZnSeO4 QDs (ZnSeO4-Hex) by heating up method (H... more Synthesis and characterization of hexamine capped ZnSeO4 QDs (ZnSeO4-Hex) by heating up method (HU) was achieved. These, of two crystallite sizes, denoted QDsS1 and QDsS2; with crystallite diameters of 8.6 nm and 14.0 nm respectively. X-ray diffraction (XRD) pattern bared hexagonal close packed (hcp) crystal structure. Band gap for QDsS1 was 5.85 eV and for QDsS2 3.8 to 4.3 eV. Hexamine (C6H10N4) cap on ZnSeO4 QDs was elucidated by Fourier Transform Infrared Spectroscopy (FTIR) and Gas Chromatography-Mass Spectroscopy (GC-MS) results. Transmission Electron Microscopy (TEM) images revealed polycrystallites of different orientation, showing crystal grains separated by tilted grain boundary folds. These QDs were tested as optical chemical nano-sensors for carcinogenic organic pollutants: Anthracene (ANTH), Benzo (a) pyrene (BaP), pyrene (PRN) and pyridine (py). Results revealed that, when the organic pollutants interacted with the QDs, they caused characteristic changes in the way these nanoparticles interacted with characteristic fluorescence and absorbance spectrum.

In this paper, the influence of contact time, initial pH and metal ion concentrations on the adso... more In this paper, the influence of contact time, initial pH and metal ion concentrations on the adsorption properties of a freshwater green alga (Spirogyra sp.) biomass was studied. Several model solutions of selected heavy metals (Cd, Cu, Cr, Pb) were put into contact with the green algae-based sorbent for different time periods. After the treatment, the concentrations of heavy metals in model solutions were determined using flame atomic absorption spectrometry (FAAS) and inductively-coupled plasmaoptical emission spectrometry (ICP-OES). Fourier transform infrared spectroscopy (FTIR) was used to reveal which functional groups were responsible for the green algae biosorption properties. Adsorption capacities were found to be 22.52, 38.19, 35.59 and 94.34 mg/g for Cd, Cr, Cu and Pb, respectively, at contact times of 15-50 minutes and initial metal ion concentrations of 500-700 µg/g. The optimum pH for biosorption of Cd, Cr, Cu and Pb were 5.5, 5.8, 5.9 and 5.0, respectively. The biosorption process followed second order kinetics and fittedthe Langmuir isotherm model. Biomonitoring studies suggested the possible use of this freshwater green algaas a bioindicator, with mean concentration factors for the selected elements in the range of 367-7154.

Journal of Agricultural Science and Technology, 2016

The international Convention on the Elimination of Persistent Organic Pollutants (POPs) lists med... more The international Convention on the Elimination of Persistent Organic Pollutants (POPs) lists medical waste incinerators among the main dioxin and furans sources in the environment. However, medical waste incinerators emit a wide range of pollutants besides dioxins and furans. These include heavy metals (lead, mercury and cadmium), fine dust particles, hydrogen chloride, sulphur dioxide, carbon monoxide, nitrogen oxides and other pollutants such as Products of Incomplete Combustion (PICs) into the atmosphere. The composition of health care waste generated can guide decisions on what disposal method is required for a particular health care facility. The purpose of this study was to evaluate health care waste management practices and compliance to the burn technology among the selected hospitals in Kiambu County, Kenya. Questionnaires were used for collecting information from respondents; analysis of heavy metal contaminants was done to ascertain the composition of the health care was...

Chemical Science International Journal, 2019

Agricultural activities, discharge of raw sewage into farms and the rise in urbanization have gre... more Agricultural activities, discharge of raw sewage into farms and the rise in urbanization have greatly contributed to soil pollution. During the rainy season, surface runoff from farms find their way into water bodies and deposits these contaminants into Rivers and Lakes which poses a threat to both aquatic and terrestrial organisms that depend on that water source. The objective of this research was to determine the level of anions and heavy metals from sediments in River Sio, Busia County, Kenya. Five sediment samples were taken from five sampling points and the levels of anions and heavy metals in them determined. Anions were determined using Shimadzu 1800 UV/visible spectrophotometer while heavy metals were determined using Shimadzu 6200 flame atomic absorption spectrophotometer (AAS). Copper, lead and nickel were above the allowed WHO limits while cadmium was below detection limit. The levels of nitrates, phosphates and chlorides were higher during the wet season due to surface ...

Journal of Agricultural Science and Technology, Apr 6, 2014

Chemical Science International Journal, 2020

Open dumpsites are one of the main sources of heavy metals and as a result, lots of research has ... more Open dumpsites are one of the main sources of heavy metals and as a result, lots of research has been undertaken on the pseudo-total content of heavy metals in dumpsite soils, but little research on the forms in which they exist. The current research was carried out to determine levels of chromium, lead and cadmium in the various fractions of Dandora dumpsite soil and how they are fractionated in the topsoil and subsoil horizons. Samples were obtained from eight sites with depths of (0-30 cm) and (30-60 cm) for topsoil and bottom soils respectively. The modified Community Bureau of Reference (BCR) sequential extraction procedure was used and metal analysis performed using flame atomic absorption spectrophotometry. The metals (lead, chromium and cadmium) total concentration (µg/g) in the upper soil profile ranged from 42.22 to 1096.21, 38.26 to 180.60 and 11.23 to 44.22 while the lower soil profiles were 54.19 to 239.28, 30.56 to 76.48 and 9.47 to 22.56, respectively. The concentrati...

Journal of environment and earth science, 2016

Effect of effluents into rivers is of great economic, environmental and health concern. Chemical ... more Effect of effluents into rivers is of great economic, environmental and health concern. Chemical fertilizers are used extensively in modern agriculture, in order to improve yield and productivity of agricultural products. However, nutrients, leaching through the soil from agricultural activities, sewerage effluents and runoff from residential areas reaching river water resources are causing serious pollution. The purpose of this study was to determine the impact of effluent discharges on water quality of River Mathioya in Murang’a County, Kenya. Samples were collected upstream and downstream of Murang’a town along the Mathioya River. The pH, dissolved oxygen, electrical conductivity, total dissolved solid, total suspended solids and temperature were determined using the respective meters. Heavy metals were determined using flame atomic absorption spectrometry while sodium and potassium were determined using flame photometry. Nitrates and phosphates were determined using UV/Visible s...

Bulletin of the Chemical Society of Ethiopia, 2005

This paper reports results on complex formation reactions between OH^-, Cl&... more This paper reports results on complex formation reactions between OH^-, Cl^-, EDTA and carbohydrate ligands with Pb²⁺ ions at various [L_T]:[M_T] ratios and at different pH values (1.5-13.0). Differential pulse anodic stripping voltammetry (DPASV) employing an <i>ex situ</i> plated thin mercury film electrode (TMFE) was used to measure the shifts in peak potentials. Formation of simple, polyligand as well as mixed ligand complexes are reported. The reactions between the Pb(II) and the carbohydrate ligands showed pronounced pH dependency on metal forms compared to reactions with simple inorganic ions such as chloride. Modeling of the experimental data obtained with the DPASV method was done using computer software (3D-VISE). The calculated complex formation curves (CCFC) based on mass balance equations were fitted to the experimental complex formation curves (ECF...

The drive for targeting higher agricultural production needs a balanced use of nutrients which ot... more The drive for targeting higher agricultural production needs a balanced use of nutrients which otherwise create problems of soil fertility exhaustion and nutrient imbalances. The current research sampled 15 farms from Ololulunga, Narok County to determine the levels of nitrate, phosphate and sulfate using UV-VIS and data analyzed using MSTAT-C, SPSS and student ttest. The nitrate concentration varied from 32.441mg/kg to 11.108mg/kg before planting and 36.759mg/kg to 21.646mg/kg after planting. The phosphate concentration varied from 3.001mg/kg to 0.368mg/kg before planting and 9.508 mg/kg to 2.357mg/kg after planting. The sulfates concentration varied from 6.678mg/kg to 3.661mg/kg before planting and 8.028 mg/kg to 4.111 mg/kg after planting. Generally, it was observed that almost all farms had different application rates of these nutrients and maybe this depended on the financial ability of individual farmer. It was found that nitrate had the least CV% of 6.71, sulfates, 8.54% and ...

Chemical Science International Journal, 2019

Environmental pollution by heavy metals is presently a serious threat to public health. Despite t... more Environmental pollution by heavy metals is presently a serious threat to public health. Despite the toxic contaminants contained in municipal waste, most of the dumpsites remain unregulated and uncontrolled. The objective of this study was to determine the levels of Pb, Cr and Cd in the leaves of tobacco tree plants growing around the dumpsite so as to assess their impact on the environment. The pseudo-total concentration of the metals in the soil was done so as to calculate the transfer factors.pH and total organic carbon (TOC) of the soil was also determined. Soil and plant samples were collected thrice from thirty two sampling sites along the off-loading path from the centre of Dandora dumpsite up to a distance of 700 m away from the centre at depth of 0-30cm (top soil). Metal analysis was done using flame atomic absorption spectroscopy (FAAS). Pb levels ranged from 7.58±0.34 to 16.57±0.79 µg/g in the washed leaves and 9.22±0.36 to 19.27±0.40 µg/g in the unwashed leaves. Cr leve...

International Research Journal of Pure and Applied Chemistry, 2019

Water samples were taken from five sampling points and their quality assessed through analysis of... more Water samples were taken from five sampling points and their quality assessed through analysis of physical and chemical characteristics. Turbidity, temperature, conductivity, pH, dissolved oxygen and total suspended solids were determined on site during sample collection, using potable meters. Anions were determined using UV/Visible spectroscopy while heavy metals were determined using flame Atomic Absorption Spectroscopy (AAS) in accordance with AWWA standard methods. Turbidity was the highest recorded parameter during the wet season with a mean of 481.83 NTU. 53% of the parameters showed significant seasonal variation (P<0.5) with the mean concentration of 56 % of the parameters being higher during the wet season. The parameters that exceeded the WHO limit were turbidity, phosphates, lead, iron, nickel, chromium and cobalt indicating poor quality of water in River Sio. Poor agricultural practices, domestic and industrial wastewater are the main factors that contribute to pollut...

Journal of environment and earth science, 2015

This study sampled wheat farms in Ntulele area of Narok county to determine the levels of nitrate... more This study sampled wheat farms in Ntulele area of Narok county to determine the levels of nitrate, phosphate and sulfate using UV-VIS spectrophotometer and data analyzed using MSTAT-C, SPSS and student t-test. Nitrates were found to be sufficient whereas phosphates and sulfates were found to be deficient in most of the farms sampled. Sulfate had the least CV% of 8.54 followed by nitrates with 14.23% and phosphate had the highest with 21.91% an indication that all the nutrients were applied in similar rates by the farmers of Ntulele. The nutrients before and after planting were significant (p<0.05). Keywords: Nitrate, Sulfate, Phosphate, UV-VIS, Soil, Ntulele

In this paper, adsorption features of freshwater green algae as a function of contact time, initi... more In this paper, adsorption features of freshwater green algae as a function of contact time, initial pH and initial metal ion concentrations were studied using model solutions of metal ions with subsequent determination by flame atomic absorption spectrometry (FAAS). Green algae samples were employed as bioindicators of selected heavy metals in environmental water samples with determination using FAAS and ICP-OES (inductively-coupled plasma-optical emission spectrometry). The optimum pH for cadmium (Cd), chromium (Cr), copper (Cu) and lead (Pb) biosorption were found to be 5.5, 5.8, 5.9 and 5.0, respectively. The biosorption process follows second order kinetics and is well described by the Langmuir isotherm model. Adsorption capacities were found to be 22.52, 38.19, 35.59 and 94.34 mg/g for Cd, Cr, Cu and Pb, respectively, at contact times of 15-50 minutes and initial metal ion concentrations of 500-700 mg/L. Biomonitoring studies revealed great potential for freshwater green algae ...

Results of speciation studies of nickel and chromium in wastewater, surface and groundwater syste... more Results of speciation studies of nickel and chromium in wastewater, surface and groundwater systems using flame atomic absorption spectrometry (FAAS), graphite furnace atomic absorption spectrometry (GFAAS) and differential pulse adsorptive cathodic stripping voltammetry (DPAdCSV) are presented. Dimethylglyoxime (DMG) and diethylenetriaminepentaacetic acid (DTPA) were used as complexing agents for DPAdCSV determination of nickel and chromium, respectively, at a hanging mercury drop electrode (HMDE). Total nickel was in the range 3091–3201 mg L –1 in wastewater from an electroplating plant, 8.1–14.4 µg L –1