George Nyamato - Academia.edu (original) (raw)

Papers by George Nyamato

Research paper thumbnail of Perspectives and prospects of chelation extraction of heavy metals from wastewater: a review

Water Science and Technology, Jun 14, 2023

Heavy metals' contamination of water resources is a global environmental issue due to their detri... more Heavy metals' contamination of water resources is a global environmental issue due to their detrimental effects on human health. To safeguard humans and the environment, toxic heavy metals must be removed from contaminated water because they cannot be broken down. Diverse technologies are employed to reduce the levels of heavy metals in wastewater. However, these technologies suffer from being either costly or ineffective, particularly when the effluent has extremely low residual amounts. This review outlines the main accomplishments and promising future directions for solvent extraction as one of the potential methods of extracting heavy metals from water, utilizing literature reports. In addition to reviewing some of the commercial chelating reagents now in use, this article also discusses some of the obnoxious effects on human health that are associated with exposure to heavy metals.

Research paper thumbnail of Removal of heavy metals from wastewater using synthetic chelating agents

Physical sciences reviews, Nov 21, 2022

Now-days, water plays an important role in human beings, natural environment and social developme... more Now-days, water plays an important role in human beings, natural environment and social development, but the subsequences of water use are municipal wastewaters and industrial wastewaters. Therefore, how to treat wastewaters and make them reusable is not only an important task but also an urgent problem to be solved 1. Pollution by heavy metals is currently of great concern, due to the increased awareness of the potentially hazardous effects of elevated levels of these materials in the environment 2,3. Many plating industries release heavy metals such as cadmium, lead, chromium, copper, zinc, iron and nickel in wastewaters. These heavy metals that find many useful applications in our life are very harmful if discharged into natural water resources and pose a serious health hazard 4-12. The most popular method to treat heavy metal containing wastewaters is chemical precipitation that uses alkaline to raise the solution pH to allow the formation of heavy metal hydroxide precipitate followed by filtration or other solid/liquid separation processes. Although the chemical precipitation method is quite effective for heavy metal removal, the resultant heavy metal sludge is classified as a hazardous solid waste and needs to be adequately treated. Sometimes, treating heavy metal sludge is more difficult than treating heavy metal-containing wastewaters. Therefore, other methods such as electrodialysis 13-17 , reverse osmosis 16,17 , biosorption including some economic bio-adsorbent 18-23 , adsorption 24-28 and ion exchange process are developed to remove heavy metals from industrial wastewaters. Among

Research paper thumbnail of Liquid-liquid extraction of copper(II), zinc(II), cadmium(II), and lead(II) from aqueous solution and sewage effluent using phenoxy-amino ligands

Water Science and Technology

The phenoxy-amino ligands 2-(((2-(diethylamino)ethyl)amino)methyl)phenol (L1) and 2-(((2-mercapto... more The phenoxy-amino ligands 2-(((2-(diethylamino)ethyl)amino)methyl)phenol (L1) and 2-(((2-mercaptoethyl)amino)methyl)-phenol (L2) were studied as model chelating agents for liquid-liquid extraction of copper(II), zinc(II), cadmium(II), and lead(II) cations from water using dichloromethane-water biphasic system. The relative affinities of these chelating ligands for copper(II), zinc(II), cadmium(II), and lead(II) by liquid-liquid extraction were found to be in the order copper(II)> zinc(II) > cadmium(II) > lead(II). The ligands L1 and L2 showed binding efficiencies ranging from 78%–97% for copper(II), 75%–91% for zinc(II), 76%–92% for cadmium(II), and 59%–67% for lead(II). The extraction protocol was successfully applied to sewage effluent.

Research paper thumbnail of CCDC 2085317: Experimental Crystal Structure Determination

Research paper thumbnail of CCDC 1406318: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Research paper thumbnail of CCDC 1406317: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Research paper thumbnail of Phenoxy-imino ligands: coordination chemistry and binding properties with copper(II) cations

Journal of Coordination Chemistry

Abstract Reactions of 2-[{(2-hydroxyethyl)imino}methyl]phenol (L1) and 2-[1-{2-(diethylamino)ethy... more Abstract Reactions of 2-[{(2-hydroxyethyl)imino}methyl]phenol (L1) and 2-[1-{2-(diethylamino)ethylimino}ethyl]phenol (L3) with copper(II) nitrate yielded monometallic complexes [CuNO3(L1)] (1) and [CuNO3(L3)] (2), respectively. The solid-state structures of 1 and 2 confirmed the κ3-O,N,O’ and κ3-O,N,N’ tridentate binding mode of L1 and L3, respectively. The phenoxy-imino ligands 2-[{(2-hydroxyethyl)imino}methyl]phenol (L1), 2-[{(2-(diethylamino)ethylimino}-methyl]phenol (L2), 2-[1-{2-(diethylamino)ethylimino}ethyl]phenol (L3) and 2-[(2-mercaptoethylimino)methyl]phenol (L4) were also used as model chelating agents for liquid-liquid extraction of copper(II), zinc(II), cadmium(II) and lead(II) cations from water using dichloromethane as the organic solvent. The relative affinities of these chelating ligands for copper(II), zinc(II), cadmium(II) and lead(II) by liquid-liquid extraction were found to be in the order copper(II) > zinc(II) > cadmium(II) > lead(II) in line with the hard-soft acid-base interaction. The ligands L1-L4 showed extraction efficiencies ranging from 75% to 99% for copper(II), 72% to 97% for zinc(II), 64% to 87% for cadmium(II) and 51% to 74% for lead(II). The extraction protocol was successfully applied to sewage effluent. Graphical Abstract

Research paper thumbnail of CCDC 1436244: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Research paper thumbnail of CCDC 1436243: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Research paper thumbnail of CCDC 1960949: Experimental Crystal Structure Determination

Research paper thumbnail of CCDC 996379: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Research paper thumbnail of CCDC 996378: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Research paper thumbnail of CCDC 908001: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Research paper thumbnail of CCDC 908000: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Research paper thumbnail of CCDC 1480100: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Research paper thumbnail of CCDC 1479997: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Research paper thumbnail of CCDC 1479994: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Research paper thumbnail of CCDC 1036013: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Research paper thumbnail of CCDC 1053064: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Research paper thumbnail of ketones mediated by ( pyrazole ) pyridine iron ( II ) and nickel ( II ) complexes † , ‡

Structural, kinetic, and DFT studies of the transfer hydrogenation of ketones mediated by (pyrazo... more Structural, kinetic, and DFT studies of the transfer hydrogenation of ketones mediated by (pyrazole)pyridine iron(II) and nickel(II) complexes †, ‡

Research paper thumbnail of Perspectives and prospects of chelation extraction of heavy metals from wastewater: a review

Water Science and Technology, Jun 14, 2023

Heavy metals' contamination of water resources is a global environmental issue due to their detri... more Heavy metals' contamination of water resources is a global environmental issue due to their detrimental effects on human health. To safeguard humans and the environment, toxic heavy metals must be removed from contaminated water because they cannot be broken down. Diverse technologies are employed to reduce the levels of heavy metals in wastewater. However, these technologies suffer from being either costly or ineffective, particularly when the effluent has extremely low residual amounts. This review outlines the main accomplishments and promising future directions for solvent extraction as one of the potential methods of extracting heavy metals from water, utilizing literature reports. In addition to reviewing some of the commercial chelating reagents now in use, this article also discusses some of the obnoxious effects on human health that are associated with exposure to heavy metals.

Research paper thumbnail of Removal of heavy metals from wastewater using synthetic chelating agents

Physical sciences reviews, Nov 21, 2022

Now-days, water plays an important role in human beings, natural environment and social developme... more Now-days, water plays an important role in human beings, natural environment and social development, but the subsequences of water use are municipal wastewaters and industrial wastewaters. Therefore, how to treat wastewaters and make them reusable is not only an important task but also an urgent problem to be solved 1. Pollution by heavy metals is currently of great concern, due to the increased awareness of the potentially hazardous effects of elevated levels of these materials in the environment 2,3. Many plating industries release heavy metals such as cadmium, lead, chromium, copper, zinc, iron and nickel in wastewaters. These heavy metals that find many useful applications in our life are very harmful if discharged into natural water resources and pose a serious health hazard 4-12. The most popular method to treat heavy metal containing wastewaters is chemical precipitation that uses alkaline to raise the solution pH to allow the formation of heavy metal hydroxide precipitate followed by filtration or other solid/liquid separation processes. Although the chemical precipitation method is quite effective for heavy metal removal, the resultant heavy metal sludge is classified as a hazardous solid waste and needs to be adequately treated. Sometimes, treating heavy metal sludge is more difficult than treating heavy metal-containing wastewaters. Therefore, other methods such as electrodialysis 13-17 , reverse osmosis 16,17 , biosorption including some economic bio-adsorbent 18-23 , adsorption 24-28 and ion exchange process are developed to remove heavy metals from industrial wastewaters. Among

Research paper thumbnail of Liquid-liquid extraction of copper(II), zinc(II), cadmium(II), and lead(II) from aqueous solution and sewage effluent using phenoxy-amino ligands

Water Science and Technology

The phenoxy-amino ligands 2-(((2-(diethylamino)ethyl)amino)methyl)phenol (L1) and 2-(((2-mercapto... more The phenoxy-amino ligands 2-(((2-(diethylamino)ethyl)amino)methyl)phenol (L1) and 2-(((2-mercaptoethyl)amino)methyl)-phenol (L2) were studied as model chelating agents for liquid-liquid extraction of copper(II), zinc(II), cadmium(II), and lead(II) cations from water using dichloromethane-water biphasic system. The relative affinities of these chelating ligands for copper(II), zinc(II), cadmium(II), and lead(II) by liquid-liquid extraction were found to be in the order copper(II)> zinc(II) > cadmium(II) > lead(II). The ligands L1 and L2 showed binding efficiencies ranging from 78%–97% for copper(II), 75%–91% for zinc(II), 76%–92% for cadmium(II), and 59%–67% for lead(II). The extraction protocol was successfully applied to sewage effluent.

Research paper thumbnail of CCDC 2085317: Experimental Crystal Structure Determination

Research paper thumbnail of CCDC 1406318: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Research paper thumbnail of CCDC 1406317: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Research paper thumbnail of Phenoxy-imino ligands: coordination chemistry and binding properties with copper(II) cations

Journal of Coordination Chemistry

Abstract Reactions of 2-[{(2-hydroxyethyl)imino}methyl]phenol (L1) and 2-[1-{2-(diethylamino)ethy... more Abstract Reactions of 2-[{(2-hydroxyethyl)imino}methyl]phenol (L1) and 2-[1-{2-(diethylamino)ethylimino}ethyl]phenol (L3) with copper(II) nitrate yielded monometallic complexes [CuNO3(L1)] (1) and [CuNO3(L3)] (2), respectively. The solid-state structures of 1 and 2 confirmed the κ3-O,N,O’ and κ3-O,N,N’ tridentate binding mode of L1 and L3, respectively. The phenoxy-imino ligands 2-[{(2-hydroxyethyl)imino}methyl]phenol (L1), 2-[{(2-(diethylamino)ethylimino}-methyl]phenol (L2), 2-[1-{2-(diethylamino)ethylimino}ethyl]phenol (L3) and 2-[(2-mercaptoethylimino)methyl]phenol (L4) were also used as model chelating agents for liquid-liquid extraction of copper(II), zinc(II), cadmium(II) and lead(II) cations from water using dichloromethane as the organic solvent. The relative affinities of these chelating ligands for copper(II), zinc(II), cadmium(II) and lead(II) by liquid-liquid extraction were found to be in the order copper(II) > zinc(II) > cadmium(II) > lead(II) in line with the hard-soft acid-base interaction. The ligands L1-L4 showed extraction efficiencies ranging from 75% to 99% for copper(II), 72% to 97% for zinc(II), 64% to 87% for cadmium(II) and 51% to 74% for lead(II). The extraction protocol was successfully applied to sewage effluent. Graphical Abstract

Research paper thumbnail of CCDC 1436244: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Research paper thumbnail of CCDC 1436243: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Research paper thumbnail of CCDC 1960949: Experimental Crystal Structure Determination

Research paper thumbnail of CCDC 996379: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Research paper thumbnail of CCDC 996378: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Research paper thumbnail of CCDC 908001: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Research paper thumbnail of CCDC 908000: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Research paper thumbnail of CCDC 1480100: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Research paper thumbnail of CCDC 1479997: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Research paper thumbnail of CCDC 1479994: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Research paper thumbnail of CCDC 1036013: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Research paper thumbnail of CCDC 1053064: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Research paper thumbnail of ketones mediated by ( pyrazole ) pyridine iron ( II ) and nickel ( II ) complexes † , ‡

Structural, kinetic, and DFT studies of the transfer hydrogenation of ketones mediated by (pyrazo... more Structural, kinetic, and DFT studies of the transfer hydrogenation of ketones mediated by (pyrazole)pyridine iron(II) and nickel(II) complexes †, ‡