2018, Vol. 3, No. 2
Display Method:
2018, 3(2): 40-48.
doi: 10.21967/jbb.v3i2.159
Abstract:
Ultrasonication and mechanical refining pretreatments were carried out to enhance alkali swelling of bamboo fibers to improve accessibility and porosity. Cellulose-based magnetic beads were synthesized with the alkali swollen bamboo fibers and Fe3O4 nanoparticles. Compared to the fibers treated with alkali alone, the water retention value (WRV) increased by 33.87% for the fibers treated by sonication and alkali, and by 94.58% for those treated by mechanical refining and alkali. The increased WRV was attributed to disruption of the crystalline region of fibers in the combined treatments which resulted in decreased crystallinity and degree of polymerization of cellulose. Furthermore, compared with the control sample which was treated by alkali alone, the specific surface area and pore volume of the samples treated by the combined processes increased markedly, which favored the adsorption of Fe3O4 nanoparticles in the synthesis of functional magnetic cellulose beads for the applications of protein immobilization, drug carrier and wastewater treatment.
Ultrasonication and mechanical refining pretreatments were carried out to enhance alkali swelling of bamboo fibers to improve accessibility and porosity. Cellulose-based magnetic beads were synthesized with the alkali swollen bamboo fibers and Fe3O4 nanoparticles. Compared to the fibers treated with alkali alone, the water retention value (WRV) increased by 33.87% for the fibers treated by sonication and alkali, and by 94.58% for those treated by mechanical refining and alkali. The increased WRV was attributed to disruption of the crystalline region of fibers in the combined treatments which resulted in decreased crystallinity and degree of polymerization of cellulose. Furthermore, compared with the control sample which was treated by alkali alone, the specific surface area and pore volume of the samples treated by the combined processes increased markedly, which favored the adsorption of Fe3O4 nanoparticles in the synthesis of functional magnetic cellulose beads for the applications of protein immobilization, drug carrier and wastewater treatment.
2018, 3(2): 49-52.
doi: 10.21967/jbb.v3i2.119
Abstract:
Dicyandiamide-formaldehyde condensation copolymer was synthesized and used as a wet-end additive for papermaking. The retention of fibers and fines was used as a performance index. Factors were evaluated governing the performance of the polymer, including polymer dosage, pH and mixing time. The optimum dosage of the polymer was found to be 0.03% under the conditions. Overall, the polymer was effective in improving the drainage, as well as the retention of fibers and fines in papermaking process.
Dicyandiamide-formaldehyde condensation copolymer was synthesized and used as a wet-end additive for papermaking. The retention of fibers and fines was used as a performance index. Factors were evaluated governing the performance of the polymer, including polymer dosage, pH and mixing time. The optimum dosage of the polymer was found to be 0.03% under the conditions. Overall, the polymer was effective in improving the drainage, as well as the retention of fibers and fines in papermaking process.
2018, 3(2): 53-58.
doi: 10.21967/jbb.v3i2.93
Abstract:
The effect of mid-stage pulping wastewater (as shock load) on micro-aerobic magnetic activated sludge system was studied. Micro-aerobic activated sludge systems with and without magnetic particles were shocked with mid-stage wastewater for 16 days. "Recovery" experiments were conducted by using simulated wastewater for 12 days. Upon the addition of mid-stage wastewater, CODCr removal pertaining to the use of magnetic particles reached 71.57% and remained above 80% in the "recovery" experiment. However, the efficiency of the reactor in the absence of magnetic particles was only 37.29%, and reached about 40% in the "recovery" experiment. After the micro-aerobic activated sludge was shocked, the flocculation performance and surface properties of the sludge were analyzed, and the results showed that all indicators of the reactors in the presence of magnetic particles were superior to those of reactors without magnetic particles. After 12 days of "recovery", the indicators of the sludge pertaining to the reactors containing magnetic particles "recovered" completely.
The effect of mid-stage pulping wastewater (as shock load) on micro-aerobic magnetic activated sludge system was studied. Micro-aerobic activated sludge systems with and without magnetic particles were shocked with mid-stage wastewater for 16 days. "Recovery" experiments were conducted by using simulated wastewater for 12 days. Upon the addition of mid-stage wastewater, CODCr removal pertaining to the use of magnetic particles reached 71.57% and remained above 80% in the "recovery" experiment. However, the efficiency of the reactor in the absence of magnetic particles was only 37.29%, and reached about 40% in the "recovery" experiment. After the micro-aerobic activated sludge was shocked, the flocculation performance and surface properties of the sludge were analyzed, and the results showed that all indicators of the reactors in the presence of magnetic particles were superior to those of reactors without magnetic particles. After 12 days of "recovery", the indicators of the sludge pertaining to the reactors containing magnetic particles "recovered" completely.
2018, 3(2): 59-64.
doi: 10.21967/jbb.v3i2.97
Abstract:
In this study, cellulose nanofibers (CNFs) were crossed-linked with glutaraldehyde (GA) under acid condition for tailoring the mechanical properties and water-resistance of nanopaper or films. The impact of carboxyl content of CNFs, GA concentration, temperature, pH, and reaction time on the crosslinking was investigated, and the process conditions for the crosslinking were optimized. FT-IR analyses showed that CNFs/GA cross-linked nanopaper was successfully fabricated by acetalization between the -OH groups of CNFs and the -CHO groups of GA, resulting in the formation of a dense, three-dimensional network. The elastic modulus of CNFs/GA cross-linked film was 7.66GPa, 62.98% higher than that of CNFs film. The water-resistance of the cross-linked CNFs/GA films was improved. The crossed-linked CNFs/GA films was still intact after 24 h after being immersed in water, while the CNFs films almost dissolved completely after 20 min of soaking in water. This method provides a facile route to enhance the elastic modulus and water-resistance of CNFs for potential applications including bullet-proof glass interlayer, flexible electronic device, and new packing materials.
In this study, cellulose nanofibers (CNFs) were crossed-linked with glutaraldehyde (GA) under acid condition for tailoring the mechanical properties and water-resistance of nanopaper or films. The impact of carboxyl content of CNFs, GA concentration, temperature, pH, and reaction time on the crosslinking was investigated, and the process conditions for the crosslinking were optimized. FT-IR analyses showed that CNFs/GA cross-linked nanopaper was successfully fabricated by acetalization between the -OH groups of CNFs and the -CHO groups of GA, resulting in the formation of a dense, three-dimensional network. The elastic modulus of CNFs/GA cross-linked film was 7.66GPa, 62.98% higher than that of CNFs film. The water-resistance of the cross-linked CNFs/GA films was improved. The crossed-linked CNFs/GA films was still intact after 24 h after being immersed in water, while the CNFs films almost dissolved completely after 20 min of soaking in water. This method provides a facile route to enhance the elastic modulus and water-resistance of CNFs for potential applications including bullet-proof glass interlayer, flexible electronic device, and new packing materials.
2018, 3(2): 65-70.
doi: 10.21967/jbb.v3i2.166
Abstract:
The amount of rice husk waste generated in Nigeria is posing serious threat to the environment and the ecosystem. Utilizing these wastes for productive purposes has been of interest to government and researchers. This study evaluated rice hush ash (RHA) reinforced clay for use as road subgrade, using the California Bearing Ratio (CBR) as prescribed in ASTM D1883. The clay was mixed with RHA/Portland cement in the ratios of 0% (control), 2.5%, 5%, 7.5% and 10%. Results showed that the physical properties of the soil in its natural form did not meet the FMW&H guideline specification for subgrade road; thus there was a need to stabilize the soil. As the percentage of RHA increased, the strength of the soil increased, with the maximum strength observed at 5% RHA, beyond which there was decrease in the load bearing capacity of the soil. Optimal CBR ratio of 9.35% was obtained at 5% RHA, 5% Portland cement and 90% clay soil. Comparing this result with the soil at natural state (CBR=1.55%), it shows that RHA is a good improvement agent for the soil. This research can be beneficial to highway road construction in areas with similar soil conditions.
The amount of rice husk waste generated in Nigeria is posing serious threat to the environment and the ecosystem. Utilizing these wastes for productive purposes has been of interest to government and researchers. This study evaluated rice hush ash (RHA) reinforced clay for use as road subgrade, using the California Bearing Ratio (CBR) as prescribed in ASTM D1883. The clay was mixed with RHA/Portland cement in the ratios of 0% (control), 2.5%, 5%, 7.5% and 10%. Results showed that the physical properties of the soil in its natural form did not meet the FMW&H guideline specification for subgrade road; thus there was a need to stabilize the soil. As the percentage of RHA increased, the strength of the soil increased, with the maximum strength observed at 5% RHA, beyond which there was decrease in the load bearing capacity of the soil. Optimal CBR ratio of 9.35% was obtained at 5% RHA, 5% Portland cement and 90% clay soil. Comparing this result with the soil at natural state (CBR=1.55%), it shows that RHA is a good improvement agent for the soil. This research can be beneficial to highway road construction in areas with similar soil conditions.
2018, 3(2): 71-77.
doi: 10.21967/jbb.v3i2.112
Abstract:
Photo-electro-catalytic (PEC) oxidation has been widely recognized as an effective technology for advanced treatment of papermaking wastewater. To optimize the oxidation process, it is important of monitor continuously the chemical oxygen demand (COD) of inflow and outflow wastewater. However, online COD sensors are expensive difficult to maintain, and therefore COD is usually analyzed off-line in laboratories in most cases. The objective of this study is to develop an inexpensive method for on-line COD measurement. The oxidation-reduction potential (ORP), pH, and dissolved oxygen (DO) of wastewater were selected as the key parameters, which consists of four different types of artificial neural network (ANNs) methods:multi-layer perceptron neural network (MLP), back propagation neural network (BPNN), radial basis neural network (RBNN) and generalized regression neural network (GRNN). These parameters were applied in the development of COD soft-sensing models. Six batches of papermaking wastewater with different pollution loads were treated with PEC technology over a period of 90 minutes, and a total of 546 data points was collected, including the on-line measurements of ORP, pH and DO, as well as off-line COD data. The 546 data points were divided into training set (410 data, 75% of total) and validation set (136 data, 25% of total). Four statistical criteria, namely, root mean square error (RMSE), mean absolute error (MAE), mean absolute relative error (MARE), and determination coefficient (R2) were used to assess the performance of the models developed with the training set of data. The comparison of results for the four ANN models for COD soft-sensing indicated that the RBNN model behaved most favorably, which possessed precise and predictable results with R2=0.913 for the validation set. Lastly, the proposed RBNN model was applied to a new batch of PEC oxidation of papermaking wastewater, and the results indicated that the model could be applied successfully for COD soft-sensing for the wastewater.
Photo-electro-catalytic (PEC) oxidation has been widely recognized as an effective technology for advanced treatment of papermaking wastewater. To optimize the oxidation process, it is important of monitor continuously the chemical oxygen demand (COD) of inflow and outflow wastewater. However, online COD sensors are expensive difficult to maintain, and therefore COD is usually analyzed off-line in laboratories in most cases. The objective of this study is to develop an inexpensive method for on-line COD measurement. The oxidation-reduction potential (ORP), pH, and dissolved oxygen (DO) of wastewater were selected as the key parameters, which consists of four different types of artificial neural network (ANNs) methods:multi-layer perceptron neural network (MLP), back propagation neural network (BPNN), radial basis neural network (RBNN) and generalized regression neural network (GRNN). These parameters were applied in the development of COD soft-sensing models. Six batches of papermaking wastewater with different pollution loads were treated with PEC technology over a period of 90 minutes, and a total of 546 data points was collected, including the on-line measurements of ORP, pH and DO, as well as off-line COD data. The 546 data points were divided into training set (410 data, 75% of total) and validation set (136 data, 25% of total). Four statistical criteria, namely, root mean square error (RMSE), mean absolute error (MAE), mean absolute relative error (MARE), and determination coefficient (R2) were used to assess the performance of the models developed with the training set of data. The comparison of results for the four ANN models for COD soft-sensing indicated that the RBNN model behaved most favorably, which possessed precise and predictable results with R2=0.913 for the validation set. Lastly, the proposed RBNN model was applied to a new batch of PEC oxidation of papermaking wastewater, and the results indicated that the model could be applied successfully for COD soft-sensing for the wastewater.
2018, 3(2): 78-83.
doi: 10.21967/jbb.v3i2.113
Abstract:
Volatile organic pollutants such as benzene and formaldehyde are commonly detected in the ambient air of paper mills. To remove these pollutants from the air, a photo-catalytic reactor was developed in this study. The reactor had a series of honeycomb aluminum meshes coated with nanosized titanium dioxide as the catalyst for the degradation reactions of gaseous pollutants. Both formaldehyde and benzene could be completely degraded in the reactor. However, the degrading time for benzene was much longer than that for formaldehyde, and the degradation rate of benzene decreased with increasing initial benzene concentration. It was found that the reaction pathway for formaldehyde in the mixture was different from that in its single component form, and it took about two times longer time to be degraded than that for its single component form. The reaction pathway of benzene was similar in either case although the degradation time for benzene was about 50% shorter in the mixture form.
Volatile organic pollutants such as benzene and formaldehyde are commonly detected in the ambient air of paper mills. To remove these pollutants from the air, a photo-catalytic reactor was developed in this study. The reactor had a series of honeycomb aluminum meshes coated with nanosized titanium dioxide as the catalyst for the degradation reactions of gaseous pollutants. Both formaldehyde and benzene could be completely degraded in the reactor. However, the degrading time for benzene was much longer than that for formaldehyde, and the degradation rate of benzene decreased with increasing initial benzene concentration. It was found that the reaction pathway for formaldehyde in the mixture was different from that in its single component form, and it took about two times longer time to be degraded than that for its single component form. The reaction pathway of benzene was similar in either case although the degradation time for benzene was about 50% shorter in the mixture form.
2018, 3(2): 84-87.
doi: 10.21967/jbb.v3i2.143
Abstract:
Stellera chamaejasme, widely distributed on the Qinghai-Tibet Plateau, is a poisonous plant causing serious harm to grassland. Activated carbons have been prepared from the roots of Stellera chamaejasme via phosphoric acid and zinc chloride activation at500℃ for 60 min with an impregnation ratio of 3:1. Yield (25.1% -27.6%), ash (4.5%-4.9%), methylene blue (195.0 mg/g-254.5 mg/g), iodine value (720.4 mg/g-810.5 mg/g), specific surface area (1023.3 m2/g-1216.7 m2/g), specific pore volume (2.13 cm3/g-2.26 cm3/g), mesopore volume (1.30 cm3/g-1.59 cm3/g) and average pore size (5.88nm-7.45 nm) of the products were determined. The results from both the zinc chloride and phosphoric acid activation processes showed that the activated carbons of S. chamaejasme roots exhibit a characterization of natural developed mesopores.
Stellera chamaejasme, widely distributed on the Qinghai-Tibet Plateau, is a poisonous plant causing serious harm to grassland. Activated carbons have been prepared from the roots of Stellera chamaejasme via phosphoric acid and zinc chloride activation at500℃ for 60 min with an impregnation ratio of 3:1. Yield (25.1% -27.6%), ash (4.5%-4.9%), methylene blue (195.0 mg/g-254.5 mg/g), iodine value (720.4 mg/g-810.5 mg/g), specific surface area (1023.3 m2/g-1216.7 m2/g), specific pore volume (2.13 cm3/g-2.26 cm3/g), mesopore volume (1.30 cm3/g-1.59 cm3/g) and average pore size (5.88nm-7.45 nm) of the products were determined. The results from both the zinc chloride and phosphoric acid activation processes showed that the activated carbons of S. chamaejasme roots exhibit a characterization of natural developed mesopores.
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