有机酸改性活性炭吸附丙酮研究

以商业活性炭为原料,采用3种有机酸(甲酸、草酸、氨基磺酸)为改性剂制得改性活性炭。采用比表面积及孔径分析仪、扫描电子显微镜及傅立叶转换红外光谱仪考察了改性对活性炭物化性质的影响。结果表明:改性后,活性炭BET比表面积及总孔容减小,表面有不均匀的粗糙的刻蚀痕迹,同时伴随有白色晶体粒子生成,表面生成了更多的O-H、C=O、C-O、S=O等含氧官能团。从吸附等温线、吸附动力学以及吸附能角度,探讨了改性对活性炭在不同进气浓度下对丙酮吸附行为的影响。结果表明:平衡吸附量的大小顺序为:AC-FAAC-OAAC-SAAC-A,Langmuir方程和Freundlich方程均能较好地描述丙酮在活性炭上的吸附;准二阶动力学模型最适合描述活性炭对丙酮的吸附动力学过程,其拟合的相关系数R2均高于0.99。     

改性活性炭对水中对氯酚的吸附性能研究

在惰性气氛下,采用不同温度热处理脱附活性炭表面的含氧酸性官能团,从而改变活性炭表面的化学性质。以对氯酚为吸附质,考察了改性前后活性炭的平衡吸附量,研究了温度、溶液pH值对吸附剂吸附性能的影响。分别用准一级动力学方程和准二级动力学方程研究了活性炭的吸附行为。结果表明,惰性气氛下热处理活性炭能提高其对对氯酚的吸附量。     

生物炭改性土的甲烷吸附试验研究

生物覆盖层是一种新型生活垃圾填埋场覆盖层,对比传统的压实黏土覆盖层其具有较高的甲烷氧化能力,减少垃圾填埋场甲烷的释放。生物炭作为生物覆盖介质,除了提高土壤甲烷氧化能力之外,其较大的比表面积还能增加甲烷吸附能力。为更好地理解生物炭对土壤的甲烷吸附特性的影响,通过批量吸附试验研究生物炭改性土在不同甲烷初始浓度与生物炭掺量下的甲烷吸附能力。试验结果表明添加生物炭能提高土壤甲烷吸附能力,相比较原土,炭掺量为20%的改性土最大甲烷吸附量提高了一个量级,甲烷吸附能力得到明显提高主要得益于生物炭的多孔结构。并且生物炭改性土的吸附特性均符合Lagergren准二级吸附动力模型和Langmuir等温吸附模型。     

BPA的解吸特征与颗粒活性炭的再生研究

应用超纯水对吸附有双酚A(BPA)的颗粒活性炭(GAC)进行解吸试验,并考察超声和有机溶剂对饱和GAC的再生效果。结果表明,单独超纯水解吸,拟二级解吸动力学模型可较好地描述水中BPA浓度随时间的变化规律,不同温度下的解吸速率常数kd2与温度的关系符合Arrhenius公式,活化能Ea为-56.47 k J/mol;在20 k Hz的超声作用下,BPA解吸速率明显提高,且随超声功率的增大而明显加快;拟二级解吸动力学模型也能较好地描述有机溶剂对BPA的解吸规律,乙腈对BPA的解吸效果明显好于甲醇和乙醇,400 min可使饱和炭中80.1%的BPA解吸;甲醇水溶液可有效解吸BPA,且解吸效果随甲醇含量的增大而提高,但当甲醇含量由75%上升到100%时,BPA解吸效果提高幅度有限;超声与甲醇溶液联用对GAC再生会产生协同作用,促进BPA解吸,且解吸速率随超声功率的增加而增大。     

生物沥浸改性后污泥基生物炭对Pb^2+和Cd^2+的吸附

为探索利用生物沥浸改性后污泥基生物炭去除废水中Pb^2+和Cd^2+的可行性,以生物沥浸改性后污泥为原料制备生物炭,并测定了该材料的性能和吸附特性。通过单因素试验研究了pH值、生物炭投加量对吸附Pb^2+、Cd^2+性能的影响,并利用吸附动力学和热力学来揭示吸附机制。试验结果表明,经生物沥浸改性后污泥基生物炭的重金属含量降低;吸附Pb^2+和Cd^2+的最佳pH值分别为5、6,最佳生物炭投加量均为2 g/L;其对Pb^2+和Cd^2+的吸附均能较好地符合准二级动力学方程和Langmuir等温线模型,在25、35、45℃三种温度下对Pb^2+、Cd^2+的饱和吸附量分别为30.68、39.95、43.93 mg/g和19.82、28.58、32.29 mg/g,吸附过程均主要以物理吸附为主,且为吸热过程。     

高锰酸钾改性对活性炭吸附Cr(Ⅲ)的影响

采用KMnO4对活性炭进行改性,考察了KMnO4改性对活性炭吸附Cr(Ⅲ)的影响。结果表明,在pH6.0的条件下,采用KMnO4改性可提高活性炭对Cr(Ⅲ)的吸附去除率,尤其是在低pH下提高得更为明显;当KMnO4浓度为0.04mol/L时,得到的改性活性炭AC-4的吸附性能最好;在pH=6.0的条件下,与未改性活性炭相比,改性活性炭对Cr(Ⅲ)的吸附速率明显提高,25℃时AC-4的饱和吸附量提高了43%;升高温度能明显提高改性活性炭对Cr(Ⅲ)的吸附能力,40℃时AC-4对Cr(Ⅲ)的饱和吸附量是25℃时的3.61倍。改性活性炭对Cr(Ⅲ)的吸附符合Langmuir单分子层吸附规律。     

不同种类活性炭对水中典型藻致嗅味物质的吸附能力研究

选择11种国产、进口不同材质的活性炭（椰壳炭、煤质炭）,对比其对水中土臭素（GSM）和二甲基异莰醇（2-MIB）的吸附能力。通过对比不同材质、不同碘量值、不同粒径的活性炭对GSM和2-MIB的吸附能力发现,煤质炭的吸附能力优于椰壳炭,随着活性炭粒径减小,单位质量活性炭的比表面积增大,吸附能力逐渐增大。吸附机理研究表明,国产、进口活性炭对水中2-MIB和GSM的吸附过程均符合拟二级动力学,说明该吸附是一个速率控制过程;吸附等温线均较好的符合Langmuir吸附等温方程,说明该吸附是一个单分子层均匀吸附过程。其饱和吸附量分别为：进口活性炭吸附GSM均值为346.71ng/g,吸附2-MIB为355.27ng/g;国产活性炭吸附GSM均值为214.42ng/g,吸附2-MIB为222ng/g,进口活性炭对GSM和2-MIB的吸附能力明显优于国产活性炭。     

磁性粉末活性炭的制备及对磺胺甲恶唑的去除效果

采用简单的化学共沉淀法制得负载铁锰氧化物的磁性粉末活性炭(MACCs),对其物理特性进行了表征,并利用序批式反应装置研究了MACCs对水中磺胺甲恶唑(SMZ)的吸附去除效果。结果表明,MACCs具有与粉末活性炭相似的吸附性能,且具有良好的磁性,易于分离回收;MACCs的投加量和停留时间对处理效果影响较大,而搅拌速度的影响较小,当MACCs投加量400 mg/L、停留时间为10 min时,对SMZ的去除率可达到100%。MACCs对SMZ的吸附容量较大,400 mg的MACCs可有效处理28 L、SMZ浓度为1 mg/L的水样。     

活性炭改性及其吸附甲苯和丁酮的初步研究

通过微波改性,电炉直接加热改性,氢氧化钠改性,硝酸改性等几种方法对活性炭进行改性,并对改性后活性炭的吸附能力进行研究,得出微波改性和电炉直接加热改性增强了活性炭吸附能力,氢氧化钠改性和硝酸改性则明显削弱其吸附能力。     

亚甲基兰法评价活性炭滤料的研究

采用亚甲基兰法对已使用一段时间的活性炭滤料和新炭进行评价.试验结果表明:当用于处理微污染地表水时,长期运行后的煤质活性炭对亚甲基兰的吸附曲线的1/n值与新炭相比变化不大,果壳炭1/n值与煤质炭相差较大,活性炭微孔吸附竞争对有机物的吸附影响明显.煤质活性炭比果壳炭更适于处理北方地区微污染地表水,果壳炭则更适合作为生物滤料用于高负荷生物滤池.     

Anchorage of iron hydro(oxide) nanoparticles onto activated carbon to remove As(V) from water

The adsorption of arsenic (V) by granular iron hydro(oxides) has been proven to be a reliable technique. However, due to the low mechanical properties of this material, it is difficult to apply it in full scale water treatment. Hence, the aim of this research is to develop a methodology to anchor iron hydro(oxide) nanoparticles onto activated carbon, in which the iron hydro(oxide) nanoparticles will give the activated carbon an elevated active surface area for arsenic adsorption and also help avoid the blockage of the activated carbon pores. Three activated carbons were modified by employing the thermal hydrolysis of iron as the anchorage procedure. The effects of hydrolysis temperature (60-120 °C), hydrolysis time (4-16 h), and FeCl₃ concentration (0.4-3 mol Fe/L) were studied by the surface response methodology. The iron content of the modified samples ranged from 0.73 to 5.27%, with the higher end of the range pertaining to the carbons with high oxygen content. The materials containing smaller iron hydro(oxide) particles exhibited an enhanced arsenic adsorption capacity. The best adsorbent material reported an arsenic adsorption capacity of 4.56 mg As/g at 1.5 ppm As at equilibrium and pH 7.     

新型活性炭吸附技术对降低某声学实验室甲醛浓度的实验研究

针对某声学实验室内甲醛污染物浓度严重超标的问题进行了实验分析,发现污染气体主要源头为制作声学实验室内壁的消声材料.针对实验室已建成并投入使用的实际情况,提出在实验室内设置具有浸渍铜锰氧化物的活性炭净化装置,以实现对甲醛的高效吸附.实验验证表明,浸渍铜锰氧化物的活性炭材料相比普通活性炭材料对甲醛的吸附效率明显提高,由普通...     

Combined hydrous ferric oxide and quaternary ammonium surfactant tailoring of granular activated carbon for concurrent arsenate and perchlorate removal

Activated carbon was tailored with both iron and quaternary ammonium surfactants so as to concurrently remove both arsenate and perchlorate from groundwater. The iron (hydr)oxide preferentially removed the arsenate oxyanion but not perchlorate; while the quaternary ammonium preferentially removed the perchlorate oxyanion, but not the arsenate. The co-sorption of two anionic oxyanions via distinct mechanisms has yielded intriguing phenomena. Rapid small-scale column tests (RSSCTs) with these dually prepared media employed synthetic waters that were concurrently spiked with arsenate and perchlorate; and these trial results showed that the quaternary ammonium surfactants enhanced arsenate removal bed life by 25-50% when compared to activated carbon media that had been preloaded merely with iron (hydr)oxide; and the surfactant also enhanced the diffusion rate of arsenate per the Donnan effect. The authors also employed natural groundwater from Rutland, MA which contained 60 μg/L As and traces of silica, and sulfate; and the authors spiked this with 40 μg/L perchlorate. When processing this water, activated carbon that had been tailored with iron and cationic surfactant could treat 12,500 bed volumes before 10 μg/L arsenic breakthrough, and 4500 bed volumes before 6 μg/L perchlorate breakthrough. Although the quaternary ammonium surfactants exhibited only a slight capacity for removing arsenate, these surfactants did facilitate a more favorably positively charged avenue for the arsenate to diffuse through the media to the iron sorption site (i.e. via the Donnan effect).     

Chromium removal by combining the magnetic properties of iron oxide with adsorption properties of carbon nanotubes

The adsorption features of multiwall carbon nanotubes (MWCNTs) with the magnetic properties of iron oxides have been combined in a composite to produce a magnetic adsorbent. Composites of MWCNT/nano-iron oxide were prepared, and were characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and Fourier transform infrared spectroscopy (FTIR). XRD suggests that the magnetic phase formed is maghemite and/or magnetite. FESEM image shows nano-iron oxides attached to a network of MWCNTs. The adsorption capability of the composites was tested in batch and fixed bed modes. The composites have demonstrated a superior adsorption capability to that of activated carbon. The results also show that the adsorptions of Cr(III) on the composites is strongly dependent on contact time, agitation speed and pH, in the batch mode; and on flow rate and the bed thickness in the fixed bed mode. Along with the high surface area of the MWCNTs, the advantage of the magnetic composite is that it can be used as adsorbent for contaminants in water and can be subsequently controlled and removed from the medium by a simple magnetic process.     

Magnetic zeolites: a new adsorbent for removal of metallic contaminants from water

In this work the adsorption features of Na Y zeolite with the magnetic properties of iron oxides have been combined in a composite to produce a magnetic adsorbent. These magnetic composites can be used as an adsorbent for metallic contaminants in water and subsequently removed from the medium by a simple magnetic process. The zeolites:iron oxide magnetic composites, were prepared by using Na Y with weight ratio of 3:1 and were characterized by powder X-ray diffraction (XRD), magnetization measurements, chemical analyses, N(2) adsorption isotherms and M?ssbauer spectroscopy. Nitrogen adsorption isotherms showed that the surface area decreased from 505 m(2)g(-1) for the pure Na Y to 353 m(2)g(-1) for the Na Y:Fe oxide 3:1 composite. The adsorption isotherms of metal ions Cr(3+), Cu(2+) and Zn(2+) from aqueous solution onto the composites also showed that the presence of iron oxide does not affect the adsorption capacity.     

Adsorptive removal of phosphate from aqueous solutions using iron oxide tailings

This study explored the feasibility of utilizing industrial waste iron oxide tailings for phosphate removal in laboratory experiments. The experimental work emphasized on the evaluation of phosphate adsorption and desorption characteristics of the tailing material. The adsorption isotherm, kinetics, pH effect and desorption were examined in batch experiments. Five isotherm models were used for data fitting. The three-parameter equations (Redlich-Peterson and Langmuir-Freundlich) showed more applicability than the two-parameter equations (Freundlich, Langmuir and Temkin). A modified equation for calculation of the separation factor using the Langmuir-Freundlich equation constants was developed. The initial phosphate adsorption on the tailings was rapid. The adsorption kinetics can be best described by either the simple Elovich or power function equation. The phosphate adsorption on the tailings tended to decrease with an increase of pH. A phosphate desorbability of approximately 13-14% was observed, and this low desorbability likely resulted from a strong bonding between the adsorbed PO(4)(3-)and iron oxides in the tailings. Column flow-through tests using both synthetic phosphate solution and liquid hog manure confirmed the phosphate removal ability of the tailings. Due to their low cost and high capability, this type of iron oxide tailings has the potential to be utilized for cost-effective removal of phosphate from wastewater.     

Solar regeneration of powdered activated carbon impregnated with visible-light responsive photocatalyst: factors affecting performances and predictive model

This study demonstrated a green technique to regenerate spent powdered activated carbon (AC) using solar photocatalysis. The AC was impregnated with a photocatalyst photoexcitable under visible-light irradiation to yield a solar regenerable composite, namely nitrogen-doped titanium dioxide (N-TiO₂/AC). This composite exhibited bifunctional adsorptive-photocatalytic characteristics. Contaminants of emerging environmental concern, i.e. bisphenol-A (BPA), sulfamethazine (SMZ) and clofibric acid (CFA) which exhibited varying affinities for AC were chosen as target pollutants. The adsorption of BPA and SMZ by the N-TiO₂/AC was significantly higher than that of CFA. The performance of solar photocatalytic regeneration (SPR) of the spent N-TiO₂/AC composite generally increased with light intensity, N-TiO₂ loading and temperature. The regeneration efficiency (RE) for CFA-loaded spent composite was the highest compared to the other pollutant-loaded spent composites, achieving 77% within 8 h of solar irradiation (765 W m⁻²). The rate-limiting process was pollutant desorption from the interior AC sorption sites. A kinetic model was developed to predict the transient concentration of the sorbate remaining in the spent composite during SPR. Comparison studies using solvent extraction technique indicated a different order of RE for the three pollutants, attributable to their varying solubilities in the aqueous and organic solvents.     

Biofiltration of the chlorophenol aqueous solution through the activated carbon bed

The efficiency of biofiltering the o-chlorophenol solution through the KAU-grade activated carbon is common and modified with iron oxide—was studied. Both sorbents showed high selective adsorption ability for the compound investigated. The activated carbon modified with iron oxides was found to have a positive effect on the adsorption of o-chlorophenol at low equilibrium concentrations and continuous filtration.     

Experimental study on adsorption capacity of an activated carbon-based adsorption water chiller

The objective of this study was to evaluate the adsorption capacity of a working pair for an adsorption water chiller. Activated carbon fibre–methanol, activated carbon fibre–ethanol and activated carbon pallet–ethanol were used as an adsorbent–adsorbate pair in this study. The experiment was conducted using a stainless steel adsorber, 110?mm diameter by 150?mm height, filled with adsorbent and transparent plastic evaporator, 100?ml capacity, filled with adsorbate. The experiment was performed by isobaric adsorption in the temperature range of 10–100°C at the evaporator temperature of 20°C (water chiller). An experimental investigation showed that the activated carbon fibre–methanol pair has the highest adsorption capacity (0.44?kg/kg) compared to the activated carbon fibre–ethanol and activated carbon pallet–ethanol pairs. The finding revealed that uniform structure and large surface area of adsorbent as well as low boiling point and large latent heat of adsorbate had highly significant effects on adsorption capacity. The effect of time and adsorber temperature on adsorption capacity is also discussed in this study.     

Aminopolyphosphonate removal during wastewater treatment

Phosphonates are used in large quantities in industry and household products as scale inhibitors and chelating agents. They are not biodegraded during wastewater treatment but are removed by adsorption processes. Field measurements from different wastewater treatment plants affirm that they are removed almost completely during wastewater treatment. Adsorption of nitrilotrismethylenephosphonic acid onto activated sludge, amorphous iron oxide and humic acids (HAs) was studied under controlled conditions. The adsorption onto HAs decreases sharply with increasing pH with negligible adsorption at pH above 6.5. Adsorption onto amorphous iron oxide follows a Langmuir behavior. The presence of 1 mM Ca doubles the maximum surface capacity at pH 7. Adsorption onto activated sludge is not very pH sensitive and is explained to a large extent by adsorption onto amorphous iron oxides, but the contribution of organic matter or other mineral phases cannot be ruled out.