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Papers by Cooper Langford

Research paper thumbnail of Photosensitized oxidation of SO2 at an optically transparent electrode coated with poly(vinylpyridine) co-ordinated zinc(II) tetraphenylporphine

Journal of the Chemical Society, Chemical Communications, 1983

ABSTRACT

Research paper thumbnail of Photoanation reactions of hexa(dimethyl sulphoxide)chromium(III) ion by azide and thioycanate: evidence for associative reaction

Journal of the Chemical Society, Chemical Communications, 1977

ABSTRACT

Research paper thumbnail of Mechanistic analysis of environmentally important mixed ligand complex formation; Ni2+ as an example

Inorganic and Nuclear Chemistry Letters, 1973

Research paper thumbnail of Laser photoelectrochemistry as a tool for studies of metal complex excited states

Journal of the Chemical Society, Chemical Communications, 1977

ABSTRACT

Research paper thumbnail of Paper Recycling Energetics: Some Canadian Experience

Environmental Letters, 1974

Energy calculations for manufacture of paper from logs and waste papers are reported based on dat... more Energy calculations for manufacture of paper from logs and waste papers are reported based on data on energy use from the Canadian Census of Manufactures and estimates for collection and de-inking of waste. The energy requirement of the recycling technology explored exceeds the energy requirement of manufacture from logs by 33%. It appears that forest conservation through recycling has a fossil fuel cost.

Research paper thumbnail of Preferential solvation and the thermal and photochemical racemization of tris(oxalato)chromate(III) ion

The Journal of Physical Chemistry, 1970

Research paper thumbnail of Photocatalysis—A Special Issue on a Unique Hybrid Area of Catalysis

Catalysts, 2012

Where is photocatalysis situated in the broad field of catalysis? Photocatalysis is a term that c... more Where is photocatalysis situated in the broad field of catalysis? Photocatalysis is a term that combines the basic notion of a catalyst as a material that enhances the rate as a reaction approaches equilibrium without being consumed with the notion that the reaction is accelerated by photons, which of course are consumed. Thus, it is a hybrid concept. As with other areas of catalysis, it has its heterogeneous and its homogeneous dimensions with the former dominating the research literature. Nevertheless, the homogeneous opportunities should not be overlooked. A typical example of a homogeneous case can be found with a dye photocatalyst having two oxidation states where one state can achieve an electron transfer after excitation by light, where that reaction is not feasible from the ground state. If the resulting oxidation state is thermally or photochemically unstable, a catalytic cycle can be completed. Some non-dye examples of homogeneous photocatalysts include soluble ions with multiple oxidation states, including at least one readily excitable by light, such as the polyoxometallates of tungsten or Fenton's reagent. Although photochemists prefer the term "sensitizer", excited states that transfer energy to a molecule that then reacts can be viewed as photocatalysts.

Research paper thumbnail of A BIOGEOPOLYMERIC VIEW OF HUMIC SUBSTANCES WITH APPLICATION TO PARAMAGNETIC METAL EFFECTS ON 13C NMR

Understanding Humic Substances, 1999

Research paper thumbnail of PREFERENTIAL SOLVATION IN KINETICS

Non-Aqueous Solutions–5, 1977

Research paper thumbnail of Kinetic Spectroscopy of Metal Fulvic Acid Complexes

Complexation of trace metals in natural waters, 1984

Research paper thumbnail of Solvation and the Second Coordination Sphere

NMR of Paramagnetic Molecules, 1973

Research paper thumbnail of Design of a homogeneous radiation field in an LED photo-reactor

Journal of Environmental Engineering and Science, 2014

Research paper thumbnail of Some Observations on the Development of Superior Photocatalytic Systems for Application to Water Purification by the “Adsorb and Shuttle” or the Interphase Charge Transfer Mechanisms

Molecules, 2014

Adsorb and shuttle (A/S) and interfacial charge transfer are the two major strategies for overcom... more Adsorb and shuttle (A/S) and interfacial charge transfer are the two major strategies for overcoming recombination in photocatalysis in this era of nanoparticle composites. Their relationships are considered here. A review of key literature is accompanied by a presentation of three new experiments within the overall aim of assessing the relation of these strategies. The cases presented include: A/S by a high silica zeolite/TiO2 composite, charge transfer (CT) between phases in a TiO2/WO3 composite and both A/S and CT by composites of TiO2 with powered activated carbon (AC) and single-walled carbon nanotubes (SWCNT). The opportunities presented by the two strategies for moving toward photocatalysts that could support applications for the removal of contaminants from

Research paper thumbnail of Kinetics of electron build-up in TiO2 colloids probed by hole scavenging after picosecond excitation

Journal of the Chemical Society, Chemical Communications, 1987

ABSTRACT

Research paper thumbnail of Solar energy storage using chemical potential changes associated with drying of zeolites

Solar Energy, 1979

Compact solar storage systems depend upon identification of systems which can store energy as che... more Compact solar storage systems depend upon identification of systems which can store energy as chemical potential. Simple, noncorrosive, systems that operate at reasonably low temperatures are rare. The use of the heat of adsorption of moisture on zeolite molecular sieves is discussed here. The advantages of zeolites are high heats of adsorption (as much as 80kJ mol-~), large maximum adsorption capacity (0.2-0.3kgH:O/kg adsorbent) and easy control of the store following from control of heat output by regulations of flows of moist air. The disadvantages are the relatively high upper temperature required to utilize maximal storage capacities (up to 250°C) and cost. There is reason to project falling cost.

Research paper thumbnail of Thermodynamics of the formation of Co (NH3)5Cl2+ from Co (NH3)5OH23+: Separation of environmental effects

The Journal of Physical Chemistry, 1967

Research paper thumbnail of An alternative process to treat boiler feed water for reuse

Water Environment Research

A bench-scale process to treat boiler feed water for reuse in steam generation was developed. Ind... more A bench-scale process to treat boiler feed water for reuse in steam generation was developed. Industrial water samples from a steam-assisted gravity drainage plant in northern Alberta, Canada, were obtained and samples characterized. The technology, which consists of coagulation-settling to remove oil/grease and particulates followed by an advanced oxidative treatment, led to clean water samples with negligible organic carbon. Coagulation followed by settling removed most particulates and some insoluble organics. The advanced oxidative treatment removed any remaining color in the samples, decreased the organic content to near-zero, and provided water ready for reuse.

Research paper thumbnail of Kinetics of charge transfer from zinc tetraphenylporphyrin to an axially co-ordinated pyridine

Journal of the Chemical Society, Chemical Communications, 1988

Page 1. J. CHEM. SOC., CHEM. COMMUN., 1988 307 Kinetics of Charge Transfer from Zinc Tetraphenylp... more Page 1. J. CHEM. SOC., CHEM. COMMUN., 1988 307 Kinetics of Charge Transfer from Zinc Tetraphenylporphyrin to an axially Co-ordinated Pyr id i ne Andrew M. Crouch, Devendra K. Sharma, and Cooper H. Langford" Canadian ...

Research paper thumbnail of Liquid Phase Photochemistry in Relation to Tropospheric Chemistry of Halogens

The Tropospheric Chemistry of Ozone in the Polar Regions, 1993

Research paper thumbnail of Dark electrochemistry and photoelectrochemistry of molecularly doped ion-exchange polymer blends

The Journal of Physical Chemistry, 1988

ABSTRACT

Research paper thumbnail of Photosensitized oxidation of SO2 at an optically transparent electrode coated with poly(vinylpyridine) co-ordinated zinc(II) tetraphenylporphine

Journal of the Chemical Society, Chemical Communications, 1983

ABSTRACT

Research paper thumbnail of Photoanation reactions of hexa(dimethyl sulphoxide)chromium(III) ion by azide and thioycanate: evidence for associative reaction

Journal of the Chemical Society, Chemical Communications, 1977

ABSTRACT

Research paper thumbnail of Mechanistic analysis of environmentally important mixed ligand complex formation; Ni2+ as an example

Inorganic and Nuclear Chemistry Letters, 1973

Research paper thumbnail of Laser photoelectrochemistry as a tool for studies of metal complex excited states

Journal of the Chemical Society, Chemical Communications, 1977

ABSTRACT

Research paper thumbnail of Paper Recycling Energetics: Some Canadian Experience

Environmental Letters, 1974

Energy calculations for manufacture of paper from logs and waste papers are reported based on dat... more Energy calculations for manufacture of paper from logs and waste papers are reported based on data on energy use from the Canadian Census of Manufactures and estimates for collection and de-inking of waste. The energy requirement of the recycling technology explored exceeds the energy requirement of manufacture from logs by 33%. It appears that forest conservation through recycling has a fossil fuel cost.

Research paper thumbnail of Preferential solvation and the thermal and photochemical racemization of tris(oxalato)chromate(III) ion

The Journal of Physical Chemistry, 1970

Research paper thumbnail of Photocatalysis—A Special Issue on a Unique Hybrid Area of Catalysis

Catalysts, 2012

Where is photocatalysis situated in the broad field of catalysis? Photocatalysis is a term that c... more Where is photocatalysis situated in the broad field of catalysis? Photocatalysis is a term that combines the basic notion of a catalyst as a material that enhances the rate as a reaction approaches equilibrium without being consumed with the notion that the reaction is accelerated by photons, which of course are consumed. Thus, it is a hybrid concept. As with other areas of catalysis, it has its heterogeneous and its homogeneous dimensions with the former dominating the research literature. Nevertheless, the homogeneous opportunities should not be overlooked. A typical example of a homogeneous case can be found with a dye photocatalyst having two oxidation states where one state can achieve an electron transfer after excitation by light, where that reaction is not feasible from the ground state. If the resulting oxidation state is thermally or photochemically unstable, a catalytic cycle can be completed. Some non-dye examples of homogeneous photocatalysts include soluble ions with multiple oxidation states, including at least one readily excitable by light, such as the polyoxometallates of tungsten or Fenton's reagent. Although photochemists prefer the term "sensitizer", excited states that transfer energy to a molecule that then reacts can be viewed as photocatalysts.

Research paper thumbnail of A BIOGEOPOLYMERIC VIEW OF HUMIC SUBSTANCES WITH APPLICATION TO PARAMAGNETIC METAL EFFECTS ON 13C NMR

Understanding Humic Substances, 1999

Research paper thumbnail of PREFERENTIAL SOLVATION IN KINETICS

Non-Aqueous Solutions–5, 1977

Research paper thumbnail of Kinetic Spectroscopy of Metal Fulvic Acid Complexes

Complexation of trace metals in natural waters, 1984

Research paper thumbnail of Solvation and the Second Coordination Sphere

NMR of Paramagnetic Molecules, 1973

Research paper thumbnail of Design of a homogeneous radiation field in an LED photo-reactor

Journal of Environmental Engineering and Science, 2014

Research paper thumbnail of Some Observations on the Development of Superior Photocatalytic Systems for Application to Water Purification by the “Adsorb and Shuttle” or the Interphase Charge Transfer Mechanisms

Molecules, 2014

Adsorb and shuttle (A/S) and interfacial charge transfer are the two major strategies for overcom... more Adsorb and shuttle (A/S) and interfacial charge transfer are the two major strategies for overcoming recombination in photocatalysis in this era of nanoparticle composites. Their relationships are considered here. A review of key literature is accompanied by a presentation of three new experiments within the overall aim of assessing the relation of these strategies. The cases presented include: A/S by a high silica zeolite/TiO2 composite, charge transfer (CT) between phases in a TiO2/WO3 composite and both A/S and CT by composites of TiO2 with powered activated carbon (AC) and single-walled carbon nanotubes (SWCNT). The opportunities presented by the two strategies for moving toward photocatalysts that could support applications for the removal of contaminants from

Research paper thumbnail of Kinetics of electron build-up in TiO2 colloids probed by hole scavenging after picosecond excitation

Journal of the Chemical Society, Chemical Communications, 1987

ABSTRACT

Research paper thumbnail of Solar energy storage using chemical potential changes associated with drying of zeolites

Solar Energy, 1979

Compact solar storage systems depend upon identification of systems which can store energy as che... more Compact solar storage systems depend upon identification of systems which can store energy as chemical potential. Simple, noncorrosive, systems that operate at reasonably low temperatures are rare. The use of the heat of adsorption of moisture on zeolite molecular sieves is discussed here. The advantages of zeolites are high heats of adsorption (as much as 80kJ mol-~), large maximum adsorption capacity (0.2-0.3kgH:O/kg adsorbent) and easy control of the store following from control of heat output by regulations of flows of moist air. The disadvantages are the relatively high upper temperature required to utilize maximal storage capacities (up to 250°C) and cost. There is reason to project falling cost.

Research paper thumbnail of Thermodynamics of the formation of Co (NH3)5Cl2+ from Co (NH3)5OH23+: Separation of environmental effects

The Journal of Physical Chemistry, 1967

Research paper thumbnail of An alternative process to treat boiler feed water for reuse

Water Environment Research

A bench-scale process to treat boiler feed water for reuse in steam generation was developed. Ind... more A bench-scale process to treat boiler feed water for reuse in steam generation was developed. Industrial water samples from a steam-assisted gravity drainage plant in northern Alberta, Canada, were obtained and samples characterized. The technology, which consists of coagulation-settling to remove oil/grease and particulates followed by an advanced oxidative treatment, led to clean water samples with negligible organic carbon. Coagulation followed by settling removed most particulates and some insoluble organics. The advanced oxidative treatment removed any remaining color in the samples, decreased the organic content to near-zero, and provided water ready for reuse.

Research paper thumbnail of Kinetics of charge transfer from zinc tetraphenylporphyrin to an axially co-ordinated pyridine

Journal of the Chemical Society, Chemical Communications, 1988

Page 1. J. CHEM. SOC., CHEM. COMMUN., 1988 307 Kinetics of Charge Transfer from Zinc Tetraphenylp... more Page 1. J. CHEM. SOC., CHEM. COMMUN., 1988 307 Kinetics of Charge Transfer from Zinc Tetraphenylporphyrin to an axially Co-ordinated Pyr id i ne Andrew M. Crouch, Devendra K. Sharma, and Cooper H. Langford" Canadian ...

Research paper thumbnail of Liquid Phase Photochemistry in Relation to Tropospheric Chemistry of Halogens

The Tropospheric Chemistry of Ozone in the Polar Regions, 1993

Research paper thumbnail of Dark electrochemistry and photoelectrochemistry of molecularly doped ion-exchange polymer blends

The Journal of Physical Chemistry, 1988

ABSTRACT