单频和双频复合超声对水溶液中腐殖酸的降解

针对模拟水样中的腐殖酸,采用静态实验研究了在低声能密度0.028 W·ml-1条件下,单频超声(68、80、100、125和160 kHz)和双频复合超声(X-Y轴轴向正交超声:80/125 kHz和80/160 kHz;X-X轴轴向平行超声:68/100 kHz和125/160 kHz)在不同时间下对溶解性有机碳(DOC)和三卤甲烷前体物(THMFP)的去除效果。结果表明:在同一声能密度下,低频(68和80 kHz)对DOC和THMFP的去除效果比高频(100、125和160 kHz)下的去除效果好,双频复合超声的去除效果均优于单频超声,且X-Y轴轴向正交超声降解效能均优于X-X轴轴向平行超声。双频复合超声的X-Y轴轴向正交组合80/160 kHz超声25 min去除效果最好,其中DOC和THMFP去除率分别可达到32.6%和66.6%。     

双频超声对红薯淀粉结构和性质的影响

研究了单频40 kHz、80 kHz以及双频40 kHz+80 kHz超声处理对红薯淀粉结构和性质的影响。扫描电镜分析表明,超声处理能够使淀粉颗粒表面出现损伤甚至有孔洞出现。红外光谱分析表明,超声作用没有改变淀粉的分子基团,但破坏其结晶结构,使红外结晶指数下降。淀粉-碘复合物吸收光谱分析表明,超声破坏淀粉支链结构和淀粉长链,直链淀粉含量增加。Brabender曲线表明,淀粉经超声处理后黏度降低,双频超声处理后的淀粉峰值黏度比原淀粉降低15.66%。此外,超声处理后淀粉的透明度提高,双频超声处理30 min时,透射比最大,比原淀粉增加5.3%,但是随着超声时间继续增加,透明度呈现减小的趋势。单频40 kHz、80 kHz和双频40 kHz+80 kHz比较,双频超声处理对淀粉的结构和性质影响效果最明显,80 kHz次之,40 kHz影响程度最小。     

红茶氨基酸、茶多酚、咖啡因的低强度多频超声浸取特性

用DPS系统建立了包括温度、茶水质量比、时间、超声强度和超声频率(28 kHz和40 kHz)等因素的均匀设计实验方案,探索水为溶剂,低强度(低于0.6 W.cm-2)单频、双频复合和双频交变超声浸取红茶氨基酸、茶多酚、咖啡因的浸取特性;以质量浓度、浸取率为指标,用偏最小二乘法处理实验数据,以标准化回归系数评价各因素的影响程度。结果表明,与单频超声场相比,双频超声场降低了超声作用强度54%~67%,提高了温度、茶水质量比等其他单因素作用强度34%~143%;双频交变超声场的这种作用最强。双频交变超声场降低了除温度-茶水质量比之外所有双因素的作用强度12%~75%;而双频复合超声场提高了与超声强度有关的双因素作用强度19%~1 350%,降低了与超声场无关的双因素作用强度47%~75%。90℃0.3 W.cm-23种超声场浸取5 m in,红茶3种成分浸取特性有明显差异,双频复合超声浸取氨基酸的质量浓度和浸取率最高(分别为369.4mg.L-1和55.0%);双频交变浸取茶多酚、咖啡因最好,质量浓度分别为11.4、2 749.52 mg.L-1,浸取率为39.8%、49.8%,单频超声浸取效果最差。     

复频超声降解土霉素废水

以抗生素土霉素为研究对象,采用自制复频超声波污水处理装置,通过正交实验探究超声频率、功率、超声作用时间和土霉素效价4个正交因子对去除率的影响,以及通过4组不同复频组合的超声实验,研究复频超声对土霉素去除率及COD去除率的影响.结果表明,各因素的影响权重:超声频率> 作用时间> 效价> 超声功率,超声频率对土霉素的降解起重要作用;高频复频组合条件下土霉素去除率和COD去除率比低频复频组合高,但高低频组合的复频20kHz+100kHz+200kHz条件下,土霉素去处效果最好;最佳复频组合条件下处理体积为40L的土霉素经30min复频超声作用,去除率接近100%,60 min COD去除率达90%以上.     

三频复合超声强化酯交换合成蔗糖单月桂酸酯工艺

以蔗糖、月桂酸甲酯为反应原料,二甲基亚砜为溶剂,无水碳酸钾催化,研究三频复合超声场中酯交换反应合成蔗糖单月桂酸酯。结果表明,三频复合超声相比于单频超声和双频超声,明显提高了单酯产率,53+20+40 kHz三频复合超声作用下单酯产率最高,最佳工艺为糖酯摩尔比6.4∶1,催化剂用量12.4%和反应温度77℃。此条件下,蔗糖单月桂酸酯产率为90.05%。     

剩余污泥中磷回收的试验研究

以SBR反应器运行过程产生的剩余污泥为研究对象,采用MAP法对经超声处理后的污泥中的氮、磷元素进行回收研究。考察不同超声时间（10、20、30 min）、超声频率（40、80 kHz）和pH（7.0、8.0、9.0）条件下,剩余污泥上清液中氮、磷的回收效果,以期探求最佳回收条件。结果表明污泥在超声频率为80 kHz,时间为10 min后所释放的氮、磷量最大。在最佳的磷镁比为1.8-2.0条件下用磷酸铵镁沉淀法（MAP）进行回收,当pH值为7.0,反应时间为15 min时获得最佳磷回收效果,磷回收率可达62.3%。     

超声对合成乙酸正丁酯的影响因素研究

酯化反应是一种常见的有机化学反应,合成的有机酯类被广泛地用作香料,染料和溶剂等。本文在室温下,以浓硫酸为催化剂,考察了有无超声、超声频率、超声声强和氮气通气量等参数对催化合成乙酸正丁酯的影响。实验结果表明,超声在室温下辅助合成乙酸正丁酯也有很好的效果,一系列最优化参数如下:单频条件下,声频率10kHz,输出电压200V,空气通气量0.4L/min;混频条件下,声频率10kHz和30kHz正交辐照,输出电压200V,氮气通气量0.4L/min。     

珠江底泥中天然有机物降解研究

考察了基于UVC-Fenton联合生物膜法的流程以去除珠江污泥中天然有机物(NOM)的有效性。结果表明,当溶液可溶性有机碳(DOC)的质量浓度为10 mg/L,初始p H为3、初始H_2O_2、Fe~(2+)的浓度分别为0.3、0.01 mmol/L时,UVC-Fenton对有机物溶液UV_(254)和VIS_(400)的去除率最大;在此条件下,处理14 h后,溶液DOC的质量浓度也仅下降到3.4 mg/L。而可生化性处理4 h后有机物ρ(DOC)/ρ(BDOC)可由0.13提高到0.65,即有机物中有65%可被生物膜法去除。处理4 h后样品溶液的三卤甲烷的质量浓度可降低到7.7μg/L(美国饮用水水质标准的限定值为80μg/L)。以DOC和THMFP的去除效果作为标准,UVC-Fenton联合生物膜法是一种处理被天然有机物污染水体有效的方法。     

超声波辅助提取荷叶总黄酮工艺的研究

以荷叶粉末为原料,用单因素和正交实验考察了超声提取的乙醇浓度、超声时间、超声功率、液固比对荷叶黄酮提取率的影响。结果表明,采用40倍50%的乙醇溶液,在700 W的功率(20 kHz)下超声提取40 m in的提取效果最好,黄酮得率可达14.49 mg/g,电镜显示,超声对荷叶组织产生了明显的破碎作用。     

双频超声强化酯交换合成蔗糖月桂酸单酯工艺

以蔗糖、月桂酸甲酯为主要原料,无水K_2CO_3为催化剂,研究双频超声协同强化合成蔗糖月桂酸单酯工艺。单因素和正交实验表明,超声场中强化合成蔗糖月桂单酯的最优工艺条件为:糖酯摩尔比6∶1,温度80℃,声强1.050 W/cm²,超声作用时间3 h,催化剂占月桂酸甲酯质量的12%。在此条件下,单酯产率达87.99%。     

复频超声波氧化降解苯酚废水

研究了复频超声波氧化降解水中苯酚的降解效果,并且详细探讨了影响复频超声波降解苯酚的影响因素.实验结果表明：复频超声波处理苯酚去除率远比单独22 kHz和单独40 kHz超声波处理效率之和还大,复频超声波氧化技术具有明显的协同效应,苯酚降解速率提高了1.5倍.另外在实验中通过加入Fenton试剂能够加速苯酚的降解.     

超声强化超临界CO_2萃取葵粕绿原酸工艺

绿原酸具有抗氧化、清除自由基、抑制突变与抗肿瘤等生理活性。考察了萃取温度、压力、时间、流体流量和超声功率密度对超声超临界CO2萃取绿原酸的影响,结果表明,超声波的加入可以缩短超临界CO2萃取时间、降低CO2流量和提高萃取率。工艺优化后的条件为:70%乙醇加入量为400mL/100g原料,萃取温度、压力、时间、CO2流量分别为50℃、30MPa、3.5h、3.0L/h,超声频率和功率密度分别为20kHz、100W/L。优化条件下绿原酸的萃取率达4.71%     

超声降解偶氮染料活性艳红X-3B的动力学研究

对使用超声波降解偶氮染料活性艳红X-3B废水进行了动力学研究。在理论分析反应过程的基础上,建立动力学方程,并根据实验进行动力学方程参数估算。结果表明:在反应开始的前20 min内,双频-Fenton,US(40 kHz)-Fenton,US[26.5 kHz(200 W)]-Fenton,US[26.5 kHz(50 W)]-Fenton,Fenton反应中污染物的降解过程均符合一级反应动力学,k1分别为0.172 9,0.149 4,0.131 1,0.101 5,0.094 1;反应30 min后降解过程符合0级反应动力学,k0分别为0.077 7,0.282 8,0.045 8,0.087 1,0.261 2。     

Fenton试剂与双频道超声波协同降解溶液中对氯苯酚的研究

4-Chlorophenol (4-CP) solution was treated by dual-frequency ultrasound in conjunction with Fenton reagent, and obvious improvement in the 4-CP degradation rate was observed in this advanced oxidation process.Experimental results showed that ultrasonic intensity, saturating gas and pH value affected greatly the 4-CP removal rate. Among four different saturating gases (Ar, 02, air and N2), 4-CP degradation with Ar-saturated solution was the best. However, in the view of practical wastewater treatment, using oxygen as the saturating gas would be more economical. The addition of Fenton reagent followed the first-order kinetics and increased the 4-CP degradation rate.The 4-CP removal rate increased by around 126% within 15 rain treatment. The synergetic effect of dual-frequency ultrasound with Fenton reagent on 4-CP degradation was obviously observed.     

超声对超临界CO_2萃取传质的影响

自行设计了超声强化超临界CO2萃取装置,并以人参为原料,研究了超声的功率密度、频率和超声的辐照方式对超临界CO2萃取人参皂甙传质的影响。萃取压力、萃取温度、萃取时间和CO2流量分别为25 MPa、45℃、4 h和2.5 L/h。实验结果表明,当功率密度、超声频率和辐照方式分别为100 W/L、20 kHz和3 s/6 s时,人参皂甙的萃取率是不使用超声时的1.51倍;皂甙的萃取率随超声功率的增大而升高;低频超声较高频超声更有利于萃取;超声辐照时间对皂甙的萃取率影响较小;在高压下超声对超临界CO2萃取传质强化作用更明显;在适当的低温下更有利于超声强化超临界CO2萃取。     

Improvement of Convective Drying of Carrot by Applying Power Ultrasound—Influence of Mass Load Density

Power ultrasound is considered to be a novel and promising technology with which to improve heat and mass transfer phenomena in drying processes. The aim of this work was to contribute to the knowledge of ultrasound application to air drying by addressing the influence of mass load density on the ultrasonically assisted air drying of carrot. Drying kinetics of carrot cubes were carried out (in triplicate) with or without power ultrasound application (75 W, 21.7 kHz) at 40°C, 1 m/s, and several mass load densities: 12, 24, 36, 42, 48, 60, 72, 84, 96, 108, and 120 kg/m³. The experimental results showed a significant (p < 0.05) influence of both factors, mass load density and power ultrasound application, on drying kinetics. As expected, the increase of mass load density did not affect the effective moisture diffusivity (D_e, m²/s) but produced a reduction of the mass transfer coefficient (k, kg water/m²/s). This was explained by considering perturbations in the air flow through the drying chamber thus creating preferential pathways and, as a consequence, increasing external mass transfer resistance. On the other hand, it was found that the power ultrasound application increased the mass transfer coefficient and the effective moisture diffusivity regardless of the mass load density used. However, the influence of power ultrasound was not significant at the highest mass load densities tested (108 and 120 kg/m³), which may be explained from the high ratio (acoustic energy/sample mass) found under those experimental conditions. Therefore, the application of ultrasound was considered as a useful technology with which to improve the convective drying, although its effects may be reduced at high mass load densities.     

超声辅助Fe3O4活化过一硫酸盐降解酸性红B

含偶氮型染料废水色度高、降解困难,对环境危害大,采用传统水处理方法难以达到严格的工业废水排放要求。本文选取典型偶氮染料酸性红B为研究对象,采用超声辅助Fe₃O₄活化过一硫酸盐的高级氧化方法进行处理。以酸性红B染料废水的色度去除率为指标,研究Fe₃O₄投加量、PMS投加量、超声功率、超声频率、初始染料浓度、溶液初始pH等参考对降解效果的影响规律及该法的适用范围。实验获得最优的酸性红B处理条件为Fe₃O₄ 1.0g/L,PMS 60mmol/L,超声频率50kHz,超声功率80W。结果表明,该法可在pH为3.5～8.5范围中适用,能处理初始浓度1g/L酸性红B溶液。实验还研究了催化剂循环利用性能,发现重复3次的时候色度去除率仍然可以保持在95%以上。该研究结果可为偶氮型染料工业废水的处理提供技术指导。     

Influence of the Applied Acoustic Energy on the Drying of Carrots and Lemon Peel

The application of power ultrasound could constitute a way of improving traditional convective drying systems. The different effects produced by the application of power ultrasound may influence the drying rate without provoking any significant increase in product temperature. Due to the fact that the effect of power ultrasound is product dependent, the aim of this work was to address the influence of the applied acoustic energy on the convective drying of carrot and lemon peel.

Convective drying kinetics of carrot cubes (side 8.5 mm) and lemon peel slabs (thickness 7 mm) were carried out at 40°C and 1 m/s by applying different levels of acoustic power density: 0, 4, 8, 12, 16, 21, 25, 29, 33, and 37 (kW/m³). The application of power ultrasound during drying was carried out using an airborne ultrasonic transducer (21.7 kHz). Drying kinetics were described considering a diffusion model.

In both products, the application of power ultrasound improved the effective moisture diffusivity (D_e ). The improvement was linearly proportional to the applied acoustic power density. In the case of lemon peel, the effects of power ultrasound were found over all the range tested (0–37 kW/m³), whereas in the case of carrot, it was necessary to apply an acoustic power density of over 8–12 kW/m³ to be able to observe the influence. The more intense effect of acoustic energy in lemon peel drying may be explained by the fact that lemon peel is a more porous product than carrot.     

低强度多频超声浸取碱蓬籽油

为考察碱蓬籽油不同超声浸取方法的优劣,该文利用DPS系统建立了包括温度、固液比、强度(不超过0·4W/cm2)、频率(28和40kHz)、时间和粒度等因素的均匀设计实验方案,以碱蓬籽油的质量分数和浸取率为指标,利用偏最小二乘法处理实验数据,确定最佳浸取条件。结果表明低强度单频、双频复合、双频交变超声浸取碱蓬籽油,达到最佳碱蓬籽油质量分数时所需浸取时间分别为1、1和8min;碱蓬籽油质量分数分别为18·7%,17·0%和25·1%,浸取率分别为25·4%,28·5%和30·6%。综合考虑,双频交变超声浸取有明显的优势,可进行工业化开发;而单频超声浸取适合作为分析碱蓬籽油时的提取方法。在单频超声浸取时,若从碱蓬籽油的质量分数考虑,低频高强度有利;而从浸取率考虑,则是高频低强度有利;双频超声浸取时各因素影响强度的差距明显高于单频超声,粒度的影响没有明显的规律。