Mechanism study of Cu(Ⅱ) adsorption from acidic wastewater by ultrasonic-modified municipal solid waste incineration fly ash

High concentrations of copper ions(Cu(Ⅱ)) in water will pose health risks to humans and the ecological environment. Therefore, this study aims to utilize ultrasonic-cured modified municipal solid waste incineration(MSWI) fly ash for Cu(Ⅱ) adsorption to achieve the purpose of “treating waste by waste.” The effects of p H, adsorption time, initial concentration, and temperature on the modified MSWI fly ash’s adsorption efficiency were systematically studied in this article. The adsorption performance of the modified MSWI fly ash can be enhanced by the ultrasonic modification. At pH = 2, 3 and 4, the adsorption capacity of the modified MSWI fly ash for Cu(Ⅱ) increased by 2.7, 1.9 and 1.2 times, respectively. Furthermore, it was suggested that the adsorption process of the modified MSWI fly ash can be better simulated by the pseudo-second-order kinetic model, with a maximum adsorption capacity calculated by the Langmuir model of 24.196 mg.g-1. Additionally, the adsorption process is spontaneous,endothermic, and chemisorption-dominated from the thermodynamic studies(ΔH and ΔS > 0, ΔG < 0).Finally, the enhanced adsorption performance of the modified MSWI fly ash for Cu(Ⅱ) may be attributed to electrostatic interaction and chelation effects.

Photocatalytic activity of TiO_2 supported SiO_2-Al_2O_3 aerogels prepared from industrial fly ash

A ternary composite of TiO2 and a SiO2-Al2O3 aerogel with good photocatalytic activity was prepared by a simple sol-gel method with TiO2 nanoparticles and SiO2-Al2O3 aerogels derived from industrial fly ash.The structural features of the TiO2/SiO2-Al2O3 aerogel composite were investigated by X-ray powder diffraction,Fourier transform infrared spectroscopy,transmission electron microscopy,gas adsorption measurements and diffuse reflectance UV-visible spectroscopy.The optimal conditions for photocatalytic degradation of 2-sec-butyl-4,6-dinitrophenol（DNBP],included an initial DNBP concentration of 0.167 mmol/L at pH = 4.86 with a catalyst concentration of 6 g/L,under visible light irradiation for 5 h.A plausible mechanism is proposed for the photocatalytic degradation of DNBP.Our composite showed higher photocatalytic activity for DNBP degradation than that of pure TiO2.This indicates that this material can serve as an efficient photocatalyst for degradation of hazardous organic pollutants in wastewater.

改性膨润土对废水中Cu^(2+)、Zn^(2+)去除效果的研究

在对钙基膨润土原土进行钠化的基础上,用阴离子表面活性剂十二烷基硫酸钠(SDS)与阳离子表面活性剂十六烷基三甲基溴化铵(CTMAB)改性制得了有机改性膨润土。通过对含Cu2+、Zn2+废水处理试验,发现Na-膨润土及有机改性膨润土对Cu2+、Zn2+的吸附符合Langmuir方程,有机改性膨润土比Na-膨润土具有更大的吸附容量。试验对影响Cu2+、Zn2+去除的吸附时间、pH、膨润土用量、温度等因素进行了优化研究。当改性膨润土用量为5.0 g.L-1时,对实际电镀废水中Cu2+、Zn2+去除率分别为97.8%和87.6%。

飞灰吸附处理电镀废水中Cu^(2+)的研究

以垃圾焚烧发电厂产生的飞灰为吸附剂,就飞灰对电镀废水中Cu2+的静态吸附特性进行了试验研究,着重探讨了平衡时间、pH值、飞灰剂量、溶液初始浓度等因素对Cu2+吸附效果的影响。结果表明,飞灰吸附处理电镀废水中Cu2+的吸附平衡时间为2h;pH值是影响飞灰吸附废水中Cu2+的重要因素,pH=6时吸附效果最好,对Cu2+的去除率可达到87.01%;飞灰对Cu2+的吸附等温线较好地符合Henry模型和Fre-undlich模型,但不符合Langmuir模型。

酸改性膨润土处理含Cu^(2+)废水实验研究

用硫酸对天然膨润土进行活化改性制得酸改性膨润土 ,研究了该土处理含Cu2 + 废水的适当条件。结果表明 :Cu2 + 初始浓度为13 .6mg/L时 ,用土量为 8g/L、pH =7、振速 15 0～ 160r/min、吸附时间 3 0min ,酸改性膨润土对Cu2 + 的去除率可达 99.9%。处理后Cu2 +

有机改性累托石吸附Cu^(2+)的性能研究

累托石经过提纯,与十二烷基二甲基苄基氯化铵(1227)有机改性后对铜冶炼工业废水中Cu2+进行了吸附研究。实验结果表明,在不调节铜冶炼工业废水pH值的条件下,有机改性累托石用量为0.03g/mL,作用时间为30min,温度为25℃,Cu2+的去除率达98.95%,处理后的水符合国家污水综合排放标准(GB8978-1996)一级标准。有机改性累托石比提纯累托石除Cu2+效果要好。

焚烧灰渣基陶粒对酸性废水中Cu^(2+)吸附的研究

针对采矿酸性废水中Cu^(2+)的污染问题,本文采用焚烧灰渣陶粒对模拟酸性废水中的Cu^(2+)进行吸附实验。结果表明:升高体系pH值和温度有利于促进吸附的进行;陶粒对Cu^(2+)的吸附符合准一级动力学模型,达到动态吸附平衡时间为8 h,其饱和吸附量为15.07 mg/g;等温吸附更符合Langmuir等温吸附模型;NaOH解吸液的最佳浓度为1.0 mol/L,解吸率高达97.23%;陶粒可稳定再生5次。研究结果可为Cu^(2+)污染酸性废水的治理提供一种新的吸附剂。

Synthesis of CeO_2/fly ash cenospheres composites as novel photocatalysts by modified pyrolysis process

A novel fly ash cenospheres（FACs）-supported CeO2 composite（CeO2/FACs） was successfully synthesized by the modified pyrolysis process.The prepared composites were characterized by X-ray diffraction（XRD）, scanning electron microscopy（SEM）, X-ray photoelectron spectroscopy（XPS）, and diffuse reflection spectra（DRS） techniques.XRD results indicated that the CeO2 film coated on cenospheres was a face-centered cubic structure.SEM images confirmed that the CeO2 film was relatively compact.XPS results showed that Ce was present as both Ce4＋ and Ce3＋ oxidation states in CeO2 film coated on FACs substrate.The bandgap of the composite was narrower compared with the pure CeO2.The as-prepared material exhibited good photocatalytic activity for the decolorization of methylene blue（MB） under visible light irradiation, and the first-order reaction rate constant（k） of 0.0028 min–1 for CeO2/FACs composite was higher than 0.0015 min–1 of pure CeO2.The fact that they floated on water meant that CeO2/FACs composites were easily recovered from water by filtration after the reaction.The recycling test revealed that the composites were quite stable during the MB photocatalytic decolorization.The CeO2/ FACs catalyst was therefore promising for practical use in the degradation of pollutants or water cleanup.

改性聚苯乙烯树脂对重金属废水的吸附效能研究

以氯甲基化聚苯乙烯树脂(氯球)为原料合成超高交联聚苯乙烯树脂JL,并采用水杨酸进行修饰,得到改性聚苯乙烯树脂JL-BHA,对JL-BHA的红外光谱进行分析,研究了JL-BHA投加量、温度以及重金属Cu^(2+)初始浓度对重金属废水的吸附效能。结果表明:JL-BHA的合成是成功的,当JL-BHA的用量从0.01g增加至0.1g时,Cu^(2+)的去除率先增加后稳定,Cu^(2+)的吸附量逐渐降低,Cu^(2+)去除率最高为84.58%。随着Cu^(2+)初始浓度的增加,JL-BHA对Cu^(2+)的吸附量也逐渐增加,但是对Cu^(2+)的去除率却逐渐下降,而温度对Cu^(2+)去除效果影响较小。

改性粉煤灰对含铅废水的吸附研究

通过对粉煤灰的硫酸改性得到酸改性粉煤灰,用其对含铅模拟废水进行吸附实验,探讨改性的最佳条件,并在最佳改性条件下制得改性粉煤灰,研究改性粉煤灰投加量、吸附时间、吸附温度以及pH值对Pb2+吸附效果的影响。结果表明,在投加量为10 g/L,吸附时间为50 min,吸附温度为50℃,pH=6时,改性粉煤灰对40μg/mL的Pb2+的去除率可达90.34%,能够较好的去除废水中的Pb2+。

热改性粉煤灰对水中铜的动态吸附研究

以热改性粉煤灰作为吸附剂,采用固定床吸附装置,探究了床层高度、流量、初始浓度等因素对Cu^(2+)动态吸附曲线的影响。在此基础上进行了动态吸附模型的研究,分别研究了Thomas、Yoon-Nelson和Adams-Bohart三种吸附模型。同时也探讨了双组分污染物体系中MFA对Cu^(2+)的动态吸附效果。结果表明,Cu^(2+)的穿透时间随初始离子浓度和流量的增加而缩短,随床层高度的增加而延长。MFA吸附Cu^(2+)的动态行为符合Thomas和Yoon-Nelson模型。降低床层高度、增加初始浓度和流量可以提高Cu^(2+)的吸附速率。根据MFA吸附Cu^(2+)前后的表征,吸附主要机理包括含氧官能团与Cu^(2+)的络合和Na+等阳离子与Cu^(2+)的离子交换。在双组分污染物体系中,溶液中的Zn^(2+)、Pb^(2+)对MFA的Cu^(2+)吸附均产生抑制作用,其影响大小为Pb^(2+)>Zn^(2+)。