2018, Vol. 3, No. 3

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Research Article
Characterization of primary and secondary wastewater treatment sludge from a pulp and board mill complex to evaluate the feasibility of utilization as a soil amendment agent and a fertilizer product
Risto Pöykiö, Gary Watkins, Olli Dahl
2018, 3(3): 88-95. doi: 10.21967/jbb.v3i3.174
In this study, we have determined the main important physical and chemical properties as well as the heavy metal concentrations of the primary and secondary wastewater treatment sludge from a pulp and board mill complex located in Finland in order to evaluate the utilization of these by-products as a soil amendment agent or a fertilizer product. Easily soluble Ca, Mg, K, Na, P and S concentrations in the sludges were extracted by ammonium acetate (CH3COONH4) and easily soluble Cu, Mn and Zn concentrations by CH3COONH4 + Na2EDTA. For the determination of total nutrient and total heavy metal concentrations in sludges, they were digested using aqua regia (3 mL HCl + 9 mL HNO3). The total heavy concentrations in the primary sludge were lower than the Finnish heavy metal limit values for fertilizer products. In the secondary sludge, all other total heavy metals than the total Cd concentration (4.8 mg/kg; d.w.) were lower than the heavy metal limit values for fertilizer products. Due to the low total heavy metal concentrations, which were lower than the Finnish limit values for fertilizer products, the primary sludge is a potential fertilizer. Although the total Cd concentration (4.8 mg/kg; d.w.) in the secondary sludge exceed the limit value of 1.5 mg/kg (d.w.) for fertilizer products, this residue may be used as a soil improver, a growing media or as a fertilizer product in landfill sites or in other closed industrial areas, because the Finnish limit values for fertilizer products are not applied at these sites.
Influence of lignin content on enzymatic saccharification of poplar wood chips by different pretreatment methods
Zhihao Wang, Min Zhang, Saisai Li, Yue Zhang, Qiang Wang, Shanshan Liu
2018, 3(3): 96-100. doi: 10.21967/jbb.v3i3.136
Bioconversion of lignocellulose to fermentable sugars is a promising approach to produce potential bio-based energy and chemicals. Pretreatment is the key step to remove or delocalize lignin in lignocellulose, thus improving enzymatic saccharification efficiency. In this study, three kinds of pretreatment methods (ethanol, bisulfite and sulfate) were employed to produce substrates with various lignin contents which were subsequently subjected to biological saccharification processes. Results showed that a lower lignin content led to a higher fermentable sugar yield based on reducing sugar release for all samples. Additionally, the sulfate pretreatment improved the enzymatic saccharification efficiency in a greater extent than the others. Fourier transform infrared (FTIR) spectroscopy confirmed the structure changes during pretreatment.
The effects of storage time on fuel properties of Jatropha biodiesel blends
Ajimotokan H. Adewale, Rabiu A. Baba, Lawal A. Rilwan
2018, 3(3): 101-106. doi: 10.21967/jbb.v3i3.167
This study investigates the effects of storage time on fuel properties of biodiesel made from Jatropha oil and its blends with mineral diesel at different percentage compositions. The influence of storage stability on selected fuel properties such as kinematic viscosity, density, pour, cloud and flash points for Jatropha biodiesel and its blends at varying storage times were investigated using standard test methods. The biodiesel obtained through trans-esterification of Jatropha oil was blended with mineral diesel to obtain fractional samples of B20 (20% biodiesel blend), B40 (40% biodiesel blend), B60 (60% biodiesel blend) and B100 (100% neat biodiesel). Results show that kinematic viscosity and density increase for each blend over the 12 weeks of storage period. Flash, cloud and pour points decrease for each blend over the period of study. B20 was observed to be the optimum blend mix as its fuel properties were relatively unchanged over the storage period when compared to that of mineral diesel. It can be implied from the research that while properties like kinematic viscosity and density deteriorate with time; flash, cloud and pour points are observed to have improved with storage time.
Effect of microfibrillated cellulose (MFC) on the properties of gelatin based composite films
Shuaishuai Yang, Haichao Li, Huizhen Sun
2018, 3(3): 107-111. doi: 10.21967/jbb.v3i3.157
Properties of gelatin composite films(with 4% glycerol as plasticizer) with different mass concentrations of microfibrillated cellulose (MFC) (0.2-1.0%) were investigated. The prepared composite films with 1.0% MFC showed the highest tensile strength (12.32 MPa) with the lowest water absorption rate (391.1%). The composite films can be dissolved in hot water of 95℃ in less than 5 minutes. However, the addition of MFC had insignificant effect on the heat shrinkage and light transmittance of the resultant composite films.
Fe/C micro electrolysis and Fenton oxidation process for the removal of recalcitrant colored pollutants from mid-stage pulping effluent
Mingyou Liu, Lu Wang, Xianying Xiao, Zhibin He
2018, 3(3): 118-122. doi: 10.21967/jbb.v3i3.56
The pulp and paper industry produces a large amount of colored effluent in the pulping, bleaching, and papermaking processes. The wastewater from the pulp washing and bleaching stages is also known as mid-stage pulping effluent, which is difficult to treat due to its toxicity and dark dolor. This paper reports a novel Fe/C micro-electrolysis process for the treatment of the mid-stage pulping effluent. Results show that this process is effective in removing the color under optimal reaction conditions. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) analyses indicate that the colored pollutants were removed from the wastewater in the Fe/C microelectrolysis by adsorption, collection and filtration mechanisms. The Fe2+ ions produced in the micro-electrolysis process functioned as Fenton's reagents with H2O2 in the follow-up oxidation stage, which enhanced the removal of chemical oxygen demand (COD) and color.
Synthesis of Caboxymethyl Chitosan for the fabrication of Chitosan/Montmorillonite Nanocomposites
Xuejiao Liu, Yi Jing
2018, 3(3): 123-127. doi: 10.21967/jbb.v3i3.116
Chitosan/montmorillonite nanocomposites can impart water vapor and oxygen barrier and antimicrobial properties to paper. However, this application is limited by the low water-solubility of chitosan. Carboxymethylation can increase the water-solubility of chitosan. In this work, carboxymethyl chitosan was synthesized by grafting with chloroacetic acid, and intercalated montmorillonite nanocomposites were prepared by intercalation of carboxymethyl chitosan with sodium-based montmorillonite. The process conditions were optimized for the fabrication of nanocomposites. Characterizations were conducted by FT-IR, 1H-NMR and XRD. FT-IR and 1H-NMR results showed that carboxyl groups were introduced into the chitosan, and carboxymethyl chitosan was generated. XRD results confirmed the insertion of CM-CTS into interlayers of Na+-MMT. As indicated from XRD results, chemical modification of chitosan resulted in enhanced intercalation. Carboxymethyl chitosan resulted in formation of exfoliated chitosan/montmorillonite nanocomposites.
Identification and characterization of slime-producing microorganisms in papermaking water loops using emulsion polymerase chain reaction techniques
Liuxin Shi, Gang Shi, Rongxia ZhuGe, Qiang Cheng, Fangfang Wu, Yonghao Ni
2018, 3(3): 128-133. doi: 10.21967/jbb.v3i3.176
Slime formation on paper machines is a critical issue that can substantially impact the quantity and quality of paper production. This problem is caused by the growth of an abundant and diverse amount of bacteria. Through the application of emulsion polymerase chain reaction (emPCR), the bacterial diversity was analyzed on paper machines and more operational taxonomic units (OTUs) were obtained. Eleven types of bacterial phyla were found that have been previously identified, including Proteobacteria (α-, β-, γ-, ε-, and φ-), Bacteroidetes, Firmicutes, Cyanobacteria, Verrucomicrobia, Actinobacteria, Spirochaetes, Chloroflexi, Deinococcus-Thermus, and Armatimonadetes. Furthermore, for the first time, there were representatives of the phyla Lentisphaerae found on paper machines. This study revealed the wide bacterial diversities of slime found on paper machines in China, which was also similar to other industrial processes.