香蕉皮吸附活性艳橙的研究

探讨了用改性香蕉皮吸附处理活性艳橙模拟废水的效果,结果表明:1∶1(体积比)硫酸改性香蕉皮的吸附性能较好。用改性香蕉皮吸附活性艳橙的最适宜条件为:常温、pH=2,吸附时间30 min,振荡速率190r/min,吸附剂用量3.5 g/L,初始浓度为5 mg/L,此时最大脱色率达96.7%,处理后的滤液为无色。     

活性艳蓝KN-R对酿酒酵母的毒性效应的研究

通过测定活性艳蓝KN-R和直接湖蓝5B的毒性与相关研究的对比,说明用酵母的复制寿命作为染料毒性测试的新方法是可行的.另外,对不同浓度活性艳蓝KN-R的毒性进行测定,并通过统计酵母细胞不同的寿命终结类型的数目对其致癌、致畸效应进行评价.研究结果表明活性艳蓝KN-R溶液浓度越大,其毒性越大,致畸、致癌效应越强.     

细菌纤维素固定化漆酶对活性艳蓝KN-R脱色的研究

采用细菌纤维素(BC)膜为载体固定化漆酶,对活性艳蓝KN-R脱色,研究了艳蓝降解的动力学和不同因素对该染料脱色的影响。结果表明,脱色后的艳蓝溶液的紫外可见吸收峰几乎完全消失,说明该染料发生降解脱色;固定化酶对艳蓝的降解符合二级动力学方程;BC膜对艳蓝的吸附符合Freundlich吸附等温线。当固定化酶的活力为84.9U时,脱色率最大为73.5%;染料浓度为50mg/L时,脱色效果较好,为81.1%;固定化酶对艳蓝的脱色在偏酸性条件下更好,最适宜的pH为5,此时的脱色率为95.2%;与游离酶相比,固定化酶的降解率提高了2倍,反应速率提高了3倍;在重复脱色5次后,脱色率降为12.2%。     

柚子皮对维多利亚蓝B的吸附性能研究

柚子皮拥有多孔疏松的结构,其本身对染料有一定的吸附作用。维多利亚蓝B是染料废水中污染比较严重的一种。对柚子皮吸附维多利亚蓝B的规律及吸附效果进行试验,以确定柚子皮对维多利亚蓝B的最佳吸附条件。结果表明:在粒径40目(0.45mm),pH=7,震荡时间60min的条件下,柚子皮可使维多利亚蓝B的去除率达到95%以上,40℃时其最大吸附容量为129.9mg/g,吸附效果良好。同时柚子皮吸附维多利亚蓝B主要以物理吸附为主,包括外部液膜扩散、表面吸附和颗粒内部扩散等过程,可以用Langmuir和Temkin等温吸附理论进行描述。     

活性艳蓝KN-R与DNA相互作用的光谱研究

采用紫外光谱和荧光光谱法研究了活性艳蓝KN-R(RBB KN-R)与DNA的相互作用.结果表明,RBBKN-R与DNA能够发生相互作用,其作用方式和程度取决于RBB KN-R浓度、离子强度、酸度和磷酸根浓度等因素.随着RBB KN-R浓度的增加,RBB KN-R-DNA的紫外光谱表现为增色效应,荧光发生猝灭.RBB K...     

异相类Fenton降解活性艳橙X-GN研究

以偶氮染料活性艳橙X-GN作为降解对象,以共沉淀法制备纳米四氧化三铁颗粒(Fe_3O_4NPS)为催化剂,并构建了高效Fe_3O_4NPS/H_2O_2异相类Fenton体系用于对活性艳橙X-GN降解的降解。实验结果显示:在[Fe_3O_4NPS]=500 mg/L,[H_2O_2]=5 mmol/L和pH=7的条件下,Fe_3O_4NPS/H_2O_2反应体系对活性艳橙X-GN的降解率高达84. 8%,矿化率也达到56. 09%。这表明此体系在中性条件下也能够达到较为理想的降解效果,有效拓宽了Fenton反应pH范围。另外,该反应体系的铁离子的溶出浓度为0. 231 mg/L,有效减少铁泥产生,材料具有一定稳定性。     

循环流速对活性污泥水解-好氧循环工艺处理活性艳蓝KN-R废水的影响

采用活性污泥水解-好氧循环工艺降解活性艳蓝KN-R废水,研究了水解、好氧反应器间循环流速对废水色度和化学需氧量(COD)去除效果的影响以及水解反应器中挥发性脂肪酸(VFA)的变化规律.研究结果表明,废水色度和COD去除率随循环流速增加呈现先增大后减小的趋势.循环流速过大,不利于COD和色度的去除.但提高循环流速,有助于减少水解反应器中VFA的积累.紫外-可见光谱分析显示,经过24 h处理后的废水,活性艳蓝KN-R的特征吸收峰降至最低,表明了活性艳蓝KN-R得到了生物降解.     

活性艳橙的脱色处理研究

探讨了分别使用粉煤灰和壳聚糖处理活性艳橙模拟废水的效果。结果表明：用粉煤灰吸附处理的工艺条件为室温下振荡2 h、振荡速度200 r/min、吸附剂用量0.01 g/mL、pH值约为7,此时最大脱色率为88%;用壳聚糖吸附处理的工艺条件为室温下振荡2 h、振荡速度200 r/min、吸附剂用量0.000 3 g/mL、pH值约为7,此时脱色率达97%以上。处理后的废水都达到了我国污水综合排放标准中的一级标准。     

CuO-CeO_2/γ-Al_2O_3负载型三维粒子电极降解水中活性艳橙X-GN的研究

采用浸渍法研制了Cu O-Ce O2/γ-Al2O3负载型粒子电极,通过扫描电镜(SEM)对粒子电极微观机构、形貌进行表征,将Cu O-Ce O2/γ-Al2O3负载型粒子电极与活性炭填充于电解槽中,考察催化剂强化电化学降解活性艳橙X-GN染料的效果,通过实验确定适宜反应条件。结果表明,Cu O-Ce O2/γ-Al2O3表面晶型明显且结构牢固,具有较大的比表面积和粗糙度;槽电压15 V,初始p H为3.83,支持电解质Na2SO4的质量浓度为16 g/L,曝气体积流量为40 L/h,在此条件下,脱色率可达99.0%以上。采用紫外-可见光谱对反应中间产物进行定性分析显示,以Cu O-Ce O2/γ-Al2O3负载型三维粒子电极降解水中活性艳橙X-GN具有很好的脱色效果。     

MODIFIED PLANTAIN PEEL AS CELLULOSE-BASED LOW-COST ADSORBENT FOR THE REMOVAL OF 2,6-DICHLOROPHENOL FROM AQUEOUS SOLUTION: ADSORPTION ISOTHERMS,KINETIC MODELING,AND THERMODYNAMIC STUDIES

In this study, the feasibility of using modified plantain peel to remove 2,6-dichlorophenol from iaqueous solutions was investigated under batch mode. The effects of physical factors such as initial 2,6-dichlorophenol concentration, contact time, biosorbent particle size, biosorbent dosage and temperature on the removal process were evaluated. The results showed that biosorption of 2,6-dichlorophenol was dependent on these factors. The equilibrium biosorption data were analyzed by the Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich (D-R) adsorption isotherm models. The four tested isotherm models provided good fits to the experimental data obtained at 30°C; however, the Freundlich isotherm model provided the best correlation (R² = 0.9874) of the experimental data. The maximum monolayer biosorption capacity (Q _max ) was found to be 14.25 mg/g. The biosorption kinetics data of 2,6-dichlorophenol were analyzed by pseudo-first-order, pseudo-second-order, Elovich, intraparticle diffusion, and liquid film diffusion models. The five kinetic models fitted well to the biosorption kinetic data; however, the pseudo-second-order kinetic model gave the best fit when the biosorption mechanism was controlled by film diffusion. Thermodynamic quantities such as standard Gibbs free energy (ΔG°), standard enthalpy (ΔH°), standard entropy change of biosorption (ΔS°), and activation energy (E_a) were evaluated, and it was found that the biosorption process was spontaneous, feasible, endothermic in nature and of dual nature, physisorption and chemisorption; however, the physisorption process was dominant. Therefore, modified plantain peel has potential for application as an effective bioadsorbent for removal of 2,6-dichlorophenol from aqueous solution.     

UTILIZATION OF MESQUITE ( Prosopis julijlora) GUM AS EMULSION STABILIZING AGENT FOR SPRAY-DRIED ENCAPSULATED ORANGE PEEL OIL

Abstract

Orange peel oil was microencapsulated. Mesquite gum and its performance for producing spray-dried powders was compared to emulsions prepared with gum arabic. Average oil droplet size of mesquite gum capsules was smaller than that of gum arabic. Emulsions made with mesquite gum showed better stability than those made with gum arabic. Encapsulation capacity of mesquite gum was found to be 80.5 % of the starting oil whereas gum arabic was able to encapsulate 93.5 %. Sensory evaluation showed that there was not significant difference (α<0.05) in flavor intensity between orange peel oil encapsulated with the two emulsifiers.     

APPLICATION OF SOME DOMESTIC WASTES AS NEW LOW-COST BIOSORBENTS FOR REMOVAL OF METHYLENE BLUE: KINETIC AND EQUILIBRIUM STUDIES

In this study, parsley stalks (PS), cucumber peels (CP), and watermelon seed hulls (WSH) were used as novel low-cost adsorbents to remove methylene blue (MB) from aqueous solutions. The biosorption of MB onto PS, CP, and WSH was investigated as a function of pH (2–10), initial dye concentration (25–450 mg/L), temperature (293–333 K), ionic strength (0.0–1.0 mol/L NaCl), and biosorbent dose (0.1–1.0 g/50 mL). While the biosorption of MB on PS followed the Freundlich isotherm, biosorption on CP and WSH followed the Langmuir isotherm at all the temperatures studied. The monolayer biosorption capacities of PS, CP, and WSH were found to be 400, 111.11, and 57.14 mg/g, respectively. The biosorption of MB onto PS followed pseudo-second-order kinetics, and the biosorption onto CP and WSH followed pseudo-first-order kinetics. Thermodynamic studies showed that the biosorption of MB onto PS, CP, and WSH was spontaneous and feasible. The pH_zpc values _of PS, CP, and WSH were found to be 6.26, 6.42, and 6.83, respectively. Desorption studies were also carried out with various desorbing agents. HCl and H₃PO₄ were more effective desorbents than other desorbents used.     

杂多酸化学吸收从天然气中脱除H_2S回收硫磺的研究

研究开发了利用杂多酸脱除天然气中H2S并回收硫磺的新工艺实验结果表明，H2S的脱除效率与溶液酸度、杂多酸浓度、H2S浓度以及吸收温度、停留时间均有关系．吸收的最佳酸度为0.1kmol／m3H2SO4，此时H2S的去除率可达99％以上．通过对比纯硫磺和H2S转化物的热重分析和微分差热分析图谱，确证了在吸收过程中H2S被氧化为硫磺，杂多酸被还原为单电子杂多兰．杂多兰可被Cl2、Fe3+和NO2氧化而再生．     

生物除铬(VI)效果及机理探讨

以特定污泥挂膜的自制厌氧生物滤床系统具有良好的去铬(VI)能力。恒流泵最佳流量为47mL/min,外加碳源使废水COD约140mg/L,铬(VI)的浓度由60mg/L左右降到0.5mg/L以下(一级排放标准),需要4h,而对照组(未加碳源)需要14h。铬(VI)浓度由64.66mg/L提高到75.53mg/L时,对系统负面影响甚微,提高到95.47mg/L时,系统出水达标所需时间延长到7.5h。添加微量金属离子与未添加微量金属离子的情况相比,处理效率提高21.26%。分析试验表明:铬(VI)的去除途径可能是由生物还原作用将六价铬还原为三价铬,形成氢氧化铬沉积于微生物表面。     

STUDY OF HG(II) REMOVAL FROM AQUEOUS SOLUTION USING LIGNOCELLULOSIC COCONUT FIBER BIOSORBENTS: EQUILIBRIUM AND KINETIC EVALUATION

Lignocellulosic coconut wastes such as pith and fiber, which are abundantly available and cheap, have the potential of being used as low-cost biosorbents for heavy metal ion removal. In this study, pristine (CF-Pristine) and NaOH-treated (CF-NaOH) coconut fibers were used as a biosorbent for Hg(II) removal from an aqueous solution. The coconut fiber biosorbent (CFB) was characterized by scanning electron microscopy (SEM) and Fourier transform-infrared (FTIR) spectroscopy. The Hg(II) sorption capacities obtained for CF-Pristine and CF-NaOH were 144.4 and 135.0 mg/g, respectively. Both the equilibrium and kinetic data of Hg(II) sorption onto CFB followed the Langmuir isotherm model and a pseudo-second-order kinetic model, respectively. A further analysis of the kinetic data suggested that the Hg(II) sorption process was governed by both intraparticle and external mass transfer processes, in which film diffusion was the rate-limiting step. These results demonstrated that both pristine- and alkali-treated coconut wastes could be potential low-cost biosorbent alternatives for the removal of Hg(II) from aqueous solutions, such as water containing Hg(II) produced in the oil and gas industry.