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71.
土壤中总石油烃预处理方法研究 总被引:1,自引:0,他引:1
采用了索氏提取法、超声波萃取法和加速溶剂萃取对土壤中的总石油烃预处理进行了研究分析,方法在0 mg/L~500 mg/L范围内均有良好的线性.采用索氏提取法时,总石油烃的方法检出限均在0.001 mg/kg~0.016 mg/kg范围内,回收率在65%~80%之间,相对标准偏差均在6.8%~12%之间;采用超声波萃取法时,总石油烃的方法检出限均在0.002 mg/kg~0.023 mg/kg范围内,回收率在60%~88%之间,相对标准偏差均在8.6%~15%之间;采用加速溶剂萃取时,总石油烃的方法检出限均在0.001 mg/kg~0.009 mg/kg范围内,回收率在70%~95%之间,相对标准偏差均在2.5%~8.8%之间.实验表明三种方法均可以作为土壤中总石油烃的预处理分析方法,但加速溶剂萃取更加快捷方便,更适合实际样品的分析. 相似文献
72.
张理扬 《中国环境管理干部学院学报》2013,(3):43-46,56
现阶段索氏萃取法、超声波萃取法、微波辅助萃取法和加压流体萃取法是主流的土壤样品前处理技术,每种方法有着各自的特点。以多环芳烃和有机氯农药为目标化合物,通过研究每种萃取方法的萃取效率,进行横向比较研究后发现,索氏萃取法的萃取效率较高,但是自动化程度不高;而加速溶剂萃取法和微波辅助萃取法在保证了样品萃取效率的前提下,具有节省溶剂、自动化程度高等特点,特别适合于大批量样品的前处理工作。 相似文献
73.
CeO2掺杂TiO2催化超声降解活性大红的研究 总被引:1,自引:0,他引:1
选取活性大红染料为降解目标物,研究了用实验室合成的氧化铈掺杂二氧化钛为催化剂存在下的超声反应。研究结果表明,CeO2掺杂TiO2催化超声降解酸性大红的效果优于非掺杂的锐钛矿型TiO2的情况。在溶液pH1.0~3.0、活性大红质量浓度为20 mg/L、溶液用量50 mL、催化剂用量0.5 g/L~1.0 g/L的条件下,用输出功率5.0 W/cm^2和频率25 kHz的超声波照射80 min,活性大红降解率可达98.4%. 相似文献
74.
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76.
高频超声降解偶氮染料活性红MX-5B废水的研究 总被引:1,自引:0,他引:1
采用高频超声降解偶氮染料活性红MX-5B模拟废水,考察了溶液初始pH值、超声参数、曝气、Fe2+浓度以及多频效应对活性红MX-5B超声降解过程的影响,并初步探讨了活性红MX-5B的超声降解规律.结果表明,酸性条件下,高频超声能有效降解MX-5B,当pH=3.5,f=418.3kHz,P=69W时,反应180 min后,MX-5B模拟废水脱色完全.微量Fe2+与超声空化产生的H2 O2形成类Fenton体系,可强化MX-5B的脱色反应.曝气有利于MX-5B脱色,但影响不大.多频超声对MX-5B的脱色效果优于单频超声处理效果.超声降解MX-5B以自由基氧化机制为主,并遵循表观一级反应动力学.染料分子中的NN形成的共轭发色体系已完全破坏,芳香结构也大部分遭到了羟基自由基的破坏. 相似文献
77.
78.
Degradation of bisphenol-A using ultrasonic irradiation assisted by
low-concentration hydrogen peroxide 总被引:1,自引:0,他引:1
Kejia Zhang Naiyun Gao Yang Deng Tsair Fuh Lin Yan M Lei Li Minghao Sui 《环境科学学报(英文版)》2011,23(1):31-36
This study investigated the degradation of bisphenol-A (BPA) by ultrasonic irradiation in the presence of different additives (H2O2,air bubbles and humic acid) under various operating conditions,i.e.,ultrasonic frequency,power intensity and power density.The results demonstrated that the BPA degradation followed pseudo first-order kinetics under different experimental conditions.The optimum power intensities were 0.9,1.8,and 3.0W/cm 2 at the frequencies of 400,670,and 800 kHz,respectively.At the fixed frequ... 相似文献
79.
Pretreatment of heterocyclic pesticide wastewater using ultrasonic/ozone
combined process 总被引:1,自引:0,他引:1
Ultrasonic/O3 combined process was employed to pretreat heterocyclic pesticide wastewater for increasing biodegradability and
reducing biological toxicity. Influences of ultrasonic frequency, ultrasonic power, probe diameter, initial pH and O3 dosage on the COD
removal were studied. The results showed that the ultrasonic/O3 process significantly improved the biodegradability and reduced the
biological toxicity of the wastewater. The ratio of BOD5/COD was increased from 0.03 to 0.55 and the EC50 increased from 11% to 52%
under ultrasonic/O3 treatment. Low ultrasonic frequency brought better COD removal. Initial pH was found to have a high influence
on the COD removal and alkaline conditions were more favorable. The influences of ultrasonic power and probe diameter were small.
With an increase in O3 dosage, COD removal was e ectively improved. The optimal operational parameters for the combined process
on COD removal were ultrasonic frequency 20 kHz, initial pH 9.00, ultrasonic power 300Wand dosage of O3 454.8 mg/(L min), under
which the e ciency of COD removal reached 67.2%. 相似文献
80.
To investigate the effect of ultrasonic pretreatment on anaerobic digestion and sludge dewaterability and further to probe into the
influencing factors on sludge dewaterability, sludge flocs were stratified into four fractions: (1) slime; (2) loosely bound extracellular
polymeric substances (LB-EPS); (3) tightly bound EPS (TB-EPS); and (4) EPS-free pellets. The results showed that ultrasonic
pretreatment increased the anaerobic digestion efficiency by 7%–8%. Anaerobic digestion without ultrasonic pretreatment deteriorated
the sludge dewaterability, with the capillary suction time (CST) increased from 1.42 to 47.3 (sec L)/g-TSS. The application of ultrasonic
pretreatment firstly deteriorated the sludge dewaterability (normalized CST increased to 44.4 (sec L)/g-TSS), while subsequent
anaerobic digestion offset this effect and ultimately decreased the normalized CST to 23.2 (sec L)/g-TSS. The dewaterability of
unsonicated sludge correlated with protein (p = 0.003) and polysaccharide (p = 0.004) concentrations in the slime fraction, while
that of sonicated sludge correlated with protein concentrations in the slime and LB-EPS fractions (p < 0.05). Fluorescent excitationemission
matrix analysis showed that the fluorescence matters in the LB-EPS fraction significantly correlated with sludge dewaterability
during anarobic digestion. 相似文献