Permeation of Cu（Ⅱ） from its aqueous solution through a supported liquid membrane （SLM） containing di（2-ethylhexyl）phosphoric acid （D2EHPA） carrier dissolved in coconut oil has been studied. The effects of C...Permeation of Cu（Ⅱ） from its aqueous solution through a supported liquid membrane （SLM） containing di（2-ethylhexyl）phosphoric acid （D2EHPA） carrier dissolved in coconut oil has been studied. The effects of Cu（Ⅱ）, pH （in feed）, H2SO4 （stripping） and D2EHPA （in membrane） concentrations have been investigated. The stability of the D2EHPA-coconut oil has also been evaluated. High Cu（Ⅱ） concentration in the feed leads to an increase in flux from 4.1 × 10^-9 to 8.9 × 10^-9 mol/（m^2·s） within the Cu（Ⅱ） concentration range 7.8×10^-4-78.6×10^-4 mol/L at pH of 4.0 in the feed and 12.4 × 10^-4 mol/L D2EHPA in the membrane phase. Increase in H2SO4 concentration in strip solution leads to an increase in copper ions flux up to 0.25 mol/L H2SO4, providing a maximum flux of 7.4 × 10^-9 mol/（m^2·s）. The optimum conditions for Cu（Ⅱ） transport are, pH of feed 4.0, 0.25 mol/L H2SO4 in strip phase and 12.4 × 10^-4 mol/L D2EHPA （membrane） in 0.5 μm pore size polytetrafluoroethylene （PTFE） membrane. It has been observed that Cu（Ⅱ） flux across the membrane tends to increase with the concentration of copper ions. Application of the method developed to copper plating bath rinse solutions has been found to be successful in the recovery of Cu（Ⅱ）.展开更多
Life on the earth is dependent on dynamic interactions between its physical, chemical and biological components. In fact, all the individual processes are responsible for regulating the environmental equilibrium which...Life on the earth is dependent on dynamic interactions between its physical, chemical and biological components. In fact, all the individual processes are responsible for regulating the environmental equilibrium which can provide biosphere for multiple forms of human life. In order to overcome on shortcomings, the use of immobilized cell bioreactor technology which provides a valuable effective for treatment of waste water is discussed. An immobilized system which in this matter is applied is about absorbed or captured microorganisms in a solid substratum to retain them in a reactor or analytical system. The multiply of these immobilized cells is done when by nutrients be supplied and then migrate to the surfaces which are referred to biofilms. The biofilms can be developed on various support systems such as polypropylene pall, rocks, sands, charcoal, ceramics, and glass beads. The controllable reaction vessels which are used for these colonized surfaces are referred to bioreactors. Bioreactors in both up flows and down flows mode which use of either batch or continuous processes principle can be operated. Synchronic with development in biotechnology, there is also an extensive development in the field of bioreactors like: pumped tower loop reactor (PTLR), liquid impelled loop reactor (LILR), multipurpose tower bioreactor (MTB), fluidized-bed and packed-bed bioreactor, that in this article are discussed them.展开更多
Medical wastes have been implicated in river pollution in developing countries and most often people depend on water from such rivers for sources of livelihood. Phthalates (endocrine disruptors) are major components i...Medical wastes have been implicated in river pollution in developing countries and most often people depend on water from such rivers for sources of livelihood. Phthalates (endocrine disruptors) are major components in medical wastes and are commonly found contaminants in aquatic environment. Most sewage treatment facilities handling medical waste are inefficient due to overuse and poor maintenance and discharge directly into rivers. This study aimed to investigate the identity and estimates the concentration of phthalates in supposed treated medical wastes from a hospital sewer and water from a receiving river. Samples were randomly collected before and after treatment by the sewer plants, while samples were randomly collected along the course of the river starting from point of discharge. Control samples were taken from upstream about 500 m along the river course. The samples were extracted by liquid-liquid chroma- tographic process using dichloromethane, after which they were cleaned up in a column of silica gel using hexane as the mobile solvent. The cleaned extracts were analyzed by HPLC. The concentrations (μg/L) of dimethyl-, diethyl-, diphenyl-, dibutyl- and di-(2-ethyl)hexyl phthalates ranged from 62.81 ± 18.53;4.74 ± 3.57;2.05 ± 1.80;11.40 ± 5.58 to 141.92 ± 35.8 respectively in the sewer waste. The receiving river had a concentration (μg/L) of 9.17 ± 14.02;0.18 ± 0.31;0.48 ± 0.84;2.84 ± 1.21;61.72 ± 38.35 respectively for dimethyl-, diethyl-, diphenyl-, dibutyl- and di-(2-ethyl) hexyl phthalates. These concentrations were higher than control and far exceeded the USEPA limits of 3 μg/l recom- mended for phthalates in water. Contaminants of aquatic environment by untreated wastes from hospitals has serious implications on public health and environment as human risks for phthalate esters downstream are high and this calls for urgent need to develop strategy to build incentives for compliance in treatment and discharge of wastes into river waters.展开更多
文摘Permeation of Cu（Ⅱ） from its aqueous solution through a supported liquid membrane （SLM） containing di（2-ethylhexyl）phosphoric acid （D2EHPA） carrier dissolved in coconut oil has been studied. The effects of Cu（Ⅱ）, pH （in feed）, H2SO4 （stripping） and D2EHPA （in membrane） concentrations have been investigated. The stability of the D2EHPA-coconut oil has also been evaluated. High Cu（Ⅱ） concentration in the feed leads to an increase in flux from 4.1 × 10^-9 to 8.9 × 10^-9 mol/（m^2·s） within the Cu（Ⅱ） concentration range 7.8×10^-4-78.6×10^-4 mol/L at pH of 4.0 in the feed and 12.4 × 10^-4 mol/L D2EHPA in the membrane phase. Increase in H2SO4 concentration in strip solution leads to an increase in copper ions flux up to 0.25 mol/L H2SO4, providing a maximum flux of 7.4 × 10^-9 mol/（m^2·s）. The optimum conditions for Cu（Ⅱ） transport are, pH of feed 4.0, 0.25 mol/L H2SO4 in strip phase and 12.4 × 10^-4 mol/L D2EHPA （membrane） in 0.5 μm pore size polytetrafluoroethylene （PTFE） membrane. It has been observed that Cu（Ⅱ） flux across the membrane tends to increase with the concentration of copper ions. Application of the method developed to copper plating bath rinse solutions has been found to be successful in the recovery of Cu（Ⅱ）.
文摘Life on the earth is dependent on dynamic interactions between its physical, chemical and biological components. In fact, all the individual processes are responsible for regulating the environmental equilibrium which can provide biosphere for multiple forms of human life. In order to overcome on shortcomings, the use of immobilized cell bioreactor technology which provides a valuable effective for treatment of waste water is discussed. An immobilized system which in this matter is applied is about absorbed or captured microorganisms in a solid substratum to retain them in a reactor or analytical system. The multiply of these immobilized cells is done when by nutrients be supplied and then migrate to the surfaces which are referred to biofilms. The biofilms can be developed on various support systems such as polypropylene pall, rocks, sands, charcoal, ceramics, and glass beads. The controllable reaction vessels which are used for these colonized surfaces are referred to bioreactors. Bioreactors in both up flows and down flows mode which use of either batch or continuous processes principle can be operated. Synchronic with development in biotechnology, there is also an extensive development in the field of bioreactors like: pumped tower loop reactor (PTLR), liquid impelled loop reactor (LILR), multipurpose tower bioreactor (MTB), fluidized-bed and packed-bed bioreactor, that in this article are discussed them.
文摘Medical wastes have been implicated in river pollution in developing countries and most often people depend on water from such rivers for sources of livelihood. Phthalates (endocrine disruptors) are major components in medical wastes and are commonly found contaminants in aquatic environment. Most sewage treatment facilities handling medical waste are inefficient due to overuse and poor maintenance and discharge directly into rivers. This study aimed to investigate the identity and estimates the concentration of phthalates in supposed treated medical wastes from a hospital sewer and water from a receiving river. Samples were randomly collected before and after treatment by the sewer plants, while samples were randomly collected along the course of the river starting from point of discharge. Control samples were taken from upstream about 500 m along the river course. The samples were extracted by liquid-liquid chroma- tographic process using dichloromethane, after which they were cleaned up in a column of silica gel using hexane as the mobile solvent. The cleaned extracts were analyzed by HPLC. The concentrations (μg/L) of dimethyl-, diethyl-, diphenyl-, dibutyl- and di-(2-ethyl)hexyl phthalates ranged from 62.81 ± 18.53;4.74 ± 3.57;2.05 ± 1.80;11.40 ± 5.58 to 141.92 ± 35.8 respectively in the sewer waste. The receiving river had a concentration (μg/L) of 9.17 ± 14.02;0.18 ± 0.31;0.48 ± 0.84;2.84 ± 1.21;61.72 ± 38.35 respectively for dimethyl-, diethyl-, diphenyl-, dibutyl- and di-(2-ethyl) hexyl phthalates. These concentrations were higher than control and far exceeded the USEPA limits of 3 μg/l recom- mended for phthalates in water. Contaminants of aquatic environment by untreated wastes from hospitals has serious implications on public health and environment as human risks for phthalate esters downstream are high and this calls for urgent need to develop strategy to build incentives for compliance in treatment and discharge of wastes into river waters.
