The available data have shown that acid-leached clays had sites for adsorption of impurities in oils. Data obtained on residual impurities in cotton and sunflower-seed oils bleached with the same clay materials produc...The available data have shown that acid-leached clays had sites for adsorption of impurities in oils. Data obtained on residual impurities in cotton and sunflower-seed oils bleached with the same clay materials produced linear Langmuir and Freundlich isotherms. The increase in constant, k with increase in both temperature of thermal activation and concentration of acid used to leach the clay, suggests that bleaching efficiency increased. The value of n decreased with increase in temperature of activation and concentration of acid used to leach the clay suggesting that bleaching capacity increased. The mineral compositions of the clays influenced their surface, structural and bleaching properties.展开更多
The bleaching of crude palm oil using activated plantain peel ash (APPA) was studied in this work. Historical data design (HDD) in response surface methodology (RSM) experimental design was employed to optimize and co...The bleaching of crude palm oil using activated plantain peel ash (APPA) was studied in this work. Historical data design (HDD) in response surface methodology (RSM) experimental design was employed to optimize and correlate the process operating parameters (temperature, time and adsorbent dosage) to the percentage bleaching efficiency. The analysis of the results showed that the quadratic effects of the operating parameters were significant. The optimum condition for the maximum adsorption efficiency of 70.04% was obtained at 160°C temperature, 60 minutes reaction time, and 4 g adsorbent dosage. The predicted bleaching efficiency of 74% was in good agreement with the optimum experimental yield. This study has revealed that APPA is a good source of adsorbent for palm oil bleaching.展开更多
Bleaching with oxygen-containing agents and recirculation of process streams in the pulp and paper industry has increased the accumulation of oxalic acid and danger for precipitation of calcium oxalate encrusts, scali...Bleaching with oxygen-containing agents and recirculation of process streams in the pulp and paper industry has increased the accumulation of oxalic acid and danger for precipitation of calcium oxalate encrusts, scaling. Analysis and control of oxalic acid in bleaching filtrates is therefore becoming increasingly important in the pulp and paper industry. Chromatographic methods, such as IC and HPLC, are generally more time-consuming but are valuable as standard methods for determination of oxalic acid. However, the instrumentation needed is expensive and stationary. In this study, an enzymatic method based on oxalate oxidase and peroxidase was developed to determine oxalic acid in authentic bleaching filtrates using a spectrophotometer. The results showed that bleaching filtrates contain some compounds interfering with the enzymatic method. Pretreatment of the samples with activated charcoal was a successful approach for decreasing problems with interference. By using dilution followed by charcoal treatment, the results obtained from five bleaching filtrates with the colorimetric method correlated very well with those obtained using IC. This study offers a selective, fast and mobile analysis method to determine oxalic acid in bleaching fiRrates from the pulp and paper industry, The convenient enzyme-based method improves the possibilities for control of critical oxalic acid concentrations in closed-loop bleaching streams.展开更多
文摘The available data have shown that acid-leached clays had sites for adsorption of impurities in oils. Data obtained on residual impurities in cotton and sunflower-seed oils bleached with the same clay materials produced linear Langmuir and Freundlich isotherms. The increase in constant, k with increase in both temperature of thermal activation and concentration of acid used to leach the clay, suggests that bleaching efficiency increased. The value of n decreased with increase in temperature of activation and concentration of acid used to leach the clay suggesting that bleaching capacity increased. The mineral compositions of the clays influenced their surface, structural and bleaching properties.
文摘The bleaching of crude palm oil using activated plantain peel ash (APPA) was studied in this work. Historical data design (HDD) in response surface methodology (RSM) experimental design was employed to optimize and correlate the process operating parameters (temperature, time and adsorbent dosage) to the percentage bleaching efficiency. The analysis of the results showed that the quadratic effects of the operating parameters were significant. The optimum condition for the maximum adsorption efficiency of 70.04% was obtained at 160°C temperature, 60 minutes reaction time, and 4 g adsorbent dosage. The predicted bleaching efficiency of 74% was in good agreement with the optimum experimental yield. This study has revealed that APPA is a good source of adsorbent for palm oil bleaching.
基金This work was supported by Vinnova and the Knowledge Foundation in Sweden.
文摘Bleaching with oxygen-containing agents and recirculation of process streams in the pulp and paper industry has increased the accumulation of oxalic acid and danger for precipitation of calcium oxalate encrusts, scaling. Analysis and control of oxalic acid in bleaching filtrates is therefore becoming increasingly important in the pulp and paper industry. Chromatographic methods, such as IC and HPLC, are generally more time-consuming but are valuable as standard methods for determination of oxalic acid. However, the instrumentation needed is expensive and stationary. In this study, an enzymatic method based on oxalate oxidase and peroxidase was developed to determine oxalic acid in authentic bleaching filtrates using a spectrophotometer. The results showed that bleaching filtrates contain some compounds interfering with the enzymatic method. Pretreatment of the samples with activated charcoal was a successful approach for decreasing problems with interference. By using dilution followed by charcoal treatment, the results obtained from five bleaching filtrates with the colorimetric method correlated very well with those obtained using IC. This study offers a selective, fast and mobile analysis method to determine oxalic acid in bleaching fiRrates from the pulp and paper industry, The convenient enzyme-based method improves the possibilities for control of critical oxalic acid concentrations in closed-loop bleaching streams.
