An onsite testing based on eight-site air sampling was carried out in an airlaid papermaking workshop in Tianjin, China. By theoretical calculation, super absorbent polymer （SAP） size and its existent state in indoo...An onsite testing based on eight-site air sampling was carried out in an airlaid papermaking workshop in Tianjin, China. By theoretical calculation, super absorbent polymer （SAP） size and its existent state in indoor static airflow were obtained. SAP content in the sampled air was tested through chemical analysis method and found to be 3.0-7.2 times that of the human health limit in production areas. The concentrations of total suspending particles （TSP） and respirable particles were achieved by weighing. Particles of the most concern differ for varied function areas. Particles smaller than 10μm are mostly produced in the main production process, and 73%-90% particles generated in packing areas are larger than 10μm. SAP raw material particles can easily changed to suspending form by inevitable extrusion and frication. Correlation between respirable particles and TSP agrees well with that in atmospheric environment.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
基金Supported by the Fund of Commission of Science Technology and Industry for National Defense (2001-949)and Province and University Cooperation Fund of Science and Technology Commission of Chongqing.
文摘An onsite testing based on eight-site air sampling was carried out in an airlaid papermaking workshop in Tianjin, China. By theoretical calculation, super absorbent polymer （SAP） size and its existent state in indoor static airflow were obtained. SAP content in the sampled air was tested through chemical analysis method and found to be 3.0-7.2 times that of the human health limit in production areas. The concentrations of total suspending particles （TSP） and respirable particles were achieved by weighing. Particles of the most concern differ for varied function areas. Particles smaller than 10μm are mostly produced in the main production process, and 73%-90% particles generated in packing areas are larger than 10μm. SAP raw material particles can easily changed to suspending form by inevitable extrusion and frication. Correlation between respirable particles and TSP agrees well with that in atmospheric environment.
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.
