Papers by Keyword: Diatomite

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Authors: Wei Liang Wang, Xue Jun Bi, Bo Zhang
Abstract: A hybrid treatment system combining enforced diatomite process followed by biological aerated filters (BAF) was developed for treatment of municipal wastewater. Most pollutants, especially phosphorus, were removed in the enforced diatomite process and BAFs took a role of polishing process. New ceramic filter media and ceramisite agitator were used in two BAFs for comparison. The results showed that when the average influent CODcr was 347mg/L, NH4+-N 49mg/L and TP 6.1mg/L, the removal efficiency was 92.6%, 99.8%, and 96.4% respectively at the operating conditions of precise diatomite dosage of 75mg/L, the sludge reflux ratio 100%, the HRT of 30min in diatomite enhanced primary treatment process and the HRT of 1.5h in BAF.
Authors: Zhi Wen Luo, Zhong Chen, Su Hong Liu
Abstract: Diatomite was modified by microwave treatment to increase their utilization value, using modified diatomite to treat ammonia-nitrogen wastewater. The experiment indicated that adsorption process of modification of the modified time by microwaves and microwave power is the impact of ammonia adsorption of the main factors. Through modification experiments by raising the capacity of diatomite adsorption ammonia nitrogen, adsorption of ammonia nitrogen increase over one time. Langmuir and Freundlich isotherms were used to fit and the experimental results show that the modified diatomite adsorption onto ammonia nitrogen accords with Langmuir and Freundlich isotherm. The maximum theoretical adsorption capacities are 5.81083mg/g.
Authors: Feng Zhan, Nan Chun Chen, Xiao Hu Zhang, Bin Huang, Zhi Neng Wu, Qian Zhu
Abstract: Mechanical properties, abrasion properties, thermal stabilities, and dynamic mechanical properties of poly (vinyl chloride) (PVC)/diatomite composites with different diatomite content prepared by melting blending were investigated. The results indicated that mechanical properties of composites have different performance due to diatomite participation, and the flexural modulus was improved. With an increase in diatomite, the abrasion resistance and thermal stability of composites were improved. Furthermore, the E' and Tg of composites could be enhanced effectively with diatomite participation. The optimum combined properties of PVC/diatomite composite were obtained with the adding of 40 phr diatomite.
Authors: Sagdat Tazhibayeva, Amir Alzhanov, Kuanyshbek Musabekov, Kairat Zhalishev
Abstract: The conditions of adsorption of Cr3 + ions at the surface of diatomite are optimized. It was shown that the adsorption of Cr3 + ions on diatomite depending on the initial concentration is 1,8-6,9 mg /g, which is caused by the occurrence of the ion exchange reaction between the silanol groups of diatomite and Cr (III) ions. The effect of pH on the binding of Cr3 + ions with diatomite was studied. It was established that acidification of the medium leads to a decrease in the degree of extraction of Cr3 + ions from solutions, due to protonation of SiOH-groups of the diatomite surface with H + ions of acids to SiOH2+. It is suggested that, along with the adsorption of Cr3 + ions on the surface of diatomite heterocoagulation of diatomite particles and hydroxocomplexes of Cr3 + ions is possible.
Authors: Wei Wei Huan, Mei Juan Tian, Zhi Yin Wang, Yu Xiang Yang
Abstract: In this paper, two calcined Zhejiang diatomite and Jilin diatomite were modified by organic amine, polyethylene glycol, organocationic ions, organofunction group and metallic ions to adsorption and immobilize enzyme, the different organo-function group and metallic ions lead to the capacity of adsorptive enzyme changing with the variation of IEP value.
Authors: Qi Yuan Gu, Gen Wu, Xi Ning Lu
Abstract: Coal process wastewater that discharged from coal conversion processes usually contains volatile phenol in high concentration. As a natural mineral, diatomite demonstrates its excellent adsorption performance especially in organic pollutants removal. Diatomite was used for phenol removal in cokingwastewater by adsorption and the effect of diatomite dosage, contact time, salinity, intitial pH conditon and reaction temperature were investigated. It was observed that the removal rate of phenol increased with an increase in the diatomite dosage and contact time. The solution salinity could inhibit the phenol adsorption onto diatomite slightly by cometitive adsorption. Alkaline conditions were especially favorable for phenol removal. The increased reaction temperature could improve phenol adsorption to a large extent as well.
Authors: Xiao Su Cheng, Zhi Li, Hui Wang, Ping An Liu, An Ze Shui, Ling Ke Zeng
Abstract: The humidity controlling materials using diatomite as the major raw material were prepared by dry pressing molding process. Effects of various diatomite contents and sintering temperatures on the final products were investigated. The samples were also characterized by X-ray diffraction (XRD), scanning electronic microscope (SEM), and then tested adsorption-desorption performances by temperature and humidity chamber. The results indicate that the equilibrium moisture adsorption reaches to 338 g/m2 when diatomite content is fixed at ~70% and sintering temperature is holding at 1050°C, respectively.
Authors: Zhi Chao Zhen, Yi He Zhang, Jun Hui Ji, Yu Xia Yin
Abstract: Zinc ions were incorporated into the holes of diatomite and the antibacterial effects of the zinc diatomite was evaluated by plate counting of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). When 1wt% of the antibacterial zinc diatomite was incorporated into paint, almost all the S. aureus and E. coli on the surface were killed. This study revealed that the antibacterial capability of zinc diatomite can kill almost all of the bacteria in the diatomite holes and the surface. The preparation and microstructure of the antibacterial zinc diatomite were also studied.
Authors: Pusit Pookmanee, Atit Wannawek, Sakchai Satienperakul, Ratchadapon Putharod, Nattapol Laorodphan, Supaporn Sangsrichan, Sukon Phanichphant
Abstract: This research studies compositions of diatomite, leonardite and pumice for utilization appropriate to the properties of materials. Chemical compositions of these materials were characterized by X–ray fluorescence spectrometry (XRF) and energy dispersive X–ray spectrometry (EDXS). The silica was major component of these materials. The morphology was investigated by scanning electron microscopy (SEM). Diatomite was cylindrical in shape, leonardite was sheet or flake in shape and pumicewas prismatic in shape. The structure was studied by X–ray diffraction (XRD). It was found that the mineral composition of diatomite, leonardite and pumice showed cristobalite low, quartz and anorthite, respectively. The functional groups were identified by Fourier transform infraredspectrometry (FTIR). The functional group of siloxane was obtained and dominated vibration in these materials. And the vibration of carboxylic, alcoholic and carbonyl groups were obtained in leonardite.
Authors: Chun Juan Dong, Zhao Yu Geng, Mei Rong Feng
Abstract: To strengthen the COD removal from actual coking wastewater, a lab-scale granular bio-film reactor was continuously operated at three stages for about 9 months: anaerobic vs. micro-aerobic (over 2 months), with and without supplement of bicarbonate (over 2 months), and with and without supplement of diatomite (about 4 months).Compared with anaerobic condition, the micro-aerobic operation could strengthen COD removal in the actual coking wastewater and increase COD removal efficiency from 21.4% to 36.4%. At micro-aerobic operation conditions, the supplement of 3g.Linfluent-1 bicarbonate could distinctly increase COD average removal efficiency from 32.9% to 65.3%, and the supplement of 6g·L-1·d-1 diatomite could significantly increase COD average removal efficiency from 33.1% to 78.1%. The supplement of bicarbonate or diatomite for the granular bio-film reactor must be an effective way for the treatment of actual coking wastewater.
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