活性炭负载氧化锆制备除磷吸附剂的最佳条件研究

采用浸渍法制备了活性炭负载氧化锆的除磷吸附剂,考察了制备条件对其除磷效果的影响,通过正交试验确定了该吸附剂的最佳制备条件。结果表明,当浸渍时间为12h、锆溶液浓度为0．4mol／L、固化温度为200℃时,所制得的吸附剂的吸附除磷效果最好,对磷的吸附量为7．8mg／g。     

方解石去除废水中高浓度磷酸盐机理与影响因素

采用X射线衍射分析(XRD),透射电镜观测(TEM),红外光谱分析(FT IR),比表面积(BET)与孔径测试(BJH)分析结合理论计算探讨方解石除磷机理;通过实验考察主要影响因素,并对除磷机理加以验证。结果表明：反应时间、反应温度、pH值、投加量对除磷效率影响显著。BET,BJH与TEM测试表明方解石在整个除磷过程中未出现多孔性结构,比表面积均小于16.0 m2/g,孔容低于0.085 cm3/g,其吸附能力很弱,吸附作用不是除磷的主要机制;XRD与FT IR测试结果显示生成CaHPO4·2H2     

改性木屑对尿液废水中氨氮的吸附性能研究

采用热解+NaOH浸泡改性处理杨木屑和杉木屑,用于吸附处理尿液废水中的氨氮,对比木屑改性前后对氨氮的吸附效果。结合吸附动力学与吸附等温线模型分析,考察了吸附剂与废水接触时间、水温、废水pH和吸附剂投加量等因素对氨氮去除效果的影响。结果表明,木屑改性后比表面积增大,孔洞结构明显,对氨氮的吸附效果较改性前有显著提升;吸附反应的最佳运行条件为投加量40 g/L,温度25℃,初始pH=8,吸附反应120 min,此时改性杨木屑、改性杉木屑对氨氮的吸附率分别达到95.32%和76.21%。     

污泥吸附剂的制备及其对亚甲基蓝的去除研究

以城市污水厂脱水污泥、锯末和焦油的混合物为原料,选择ZnCl2为活化剂制备出过渡孔发达、强度大的优质污泥吸附剂(S-AC),借助BET、FTIR、DT等现代分析测试方法对污泥吸附剂进行表征,并通过吸附动力学、吸附等温线来研究污泥吸附剂的吸附性能;同时,将吸附剂应用于亚甲基蓝溶液的处理,并选择商品活性炭(AC)进行对照试验。结果表明,制得的污泥吸附剂的BET比表面积为358.0 m2/g;在试验浓度范围内,污泥吸附剂在温度分别为20、30和40℃时对亚甲基蓝的最大吸附量分别为57.13、59.37和61.79 mg/g,试验数据均符合Freundlich吸附等温方程;吸附剂的动力学数据均符合液膜扩散方程,液膜扩散为吸附过程的主控步骤。     

改性膨润土吸附剂的制备及应用研究

以AlCl3为改性剂研究了制备改性膨润土水处理吸附剂的条件，探讨了影响改性膨润土吸附去除苯酚效果的因素。结果表明：当AlCl3投量为25g／100g原土、焙烧温度为450℃时，所制得改性膨润土吸附剂的比表面积和微孔总体积分别为350．21m^2／g和0．907cm^3／g。采用该吸附剂处理苯酚废水（苯酚浓度为200mg／L）的试验结果表明，在改性膨润土吸附剂投量为4g／L、溶液的pH值为8．5、反应时间为30min的条件下，对苯酚的去除率达到了92．2％；对数据的回归分析显示，改性膨润土对苯酚的吸附符合Freundish方程。     

载锆颗粒活性炭吸附去除水溶液中的硫酸根离子（英文）

制备负载氧化锆的颗粒活性炭(Zr-GAC),以吸附水溶液中的硫酸根离子。采用扫描电镜(SEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)和比表面积测定等方法对Zr-GAC进行表征。结果表明,Zr-GAC具有多孔的表面积,其上具有许多由氧化锆组成的团聚体。XPS分析证实,吸附剂表面存在大量的锆和羟基,氧化锆改性后的活性炭比表面积减小。采用间歇吸附实验研究了pH值对硫酸盐吸附的影响,在pH值小于10时,吸附效果较好。吸附等温线的模拟分析表明,Dubinin-Radushkevich(D-R)方程比Langmuir模型具有更好的拟合性,由D-R方程确定的在中性水溶液最大吸附量为70.14mg/g,远高于原GAC(8.9mg/g)。需要注意的是,D-R方程在测定溶液吸附的吸附能时可能存在问题,值得进一步研究。动力学研究表明,硫酸根在Zr-GAC上的吸附速度较快,并遵循准二级动力学方程。此外,温度的升高在一定程度上可能利于硫酸盐的吸附。Zr-GAC具有很好的吸附水溶液中硫酸根离子的潜力,特别是其吸附容量约为载锆生物炭吸附剂的两倍,pH值的适用范围更广。     

坡缕石、硅胶及活性炭吸附VOC气体特性研究

考察了水、乙醇和甲苯分别在坡缕石上的吸附/脱附性能,同时与硅胶和活性炭的吸附/脱附性能进行对比。结果表明,吸附剂的吸附/脱附性能主要取决于吸附剂的比表面积和孔道尺寸,极性吸附剂的吸附/脱附性能还受吸附剂和吸附质极性的影响。三种吸附剂对水的吸附性能依次为:活性炭硅胶坡缕石。三种吸附剂对乙醇和甲苯的吸附量大小依次为:硅胶活性炭坡缕石。三种吸附剂的脱附再生性能依次为:坡缕石硅胶活性炭,其中乙醇和甲苯两种极性较小的VOC分子相对于极性较大的水分子更容易从坡缕石和硅胶中脱附。     

天然气吸附储存技术

阐述了吸附天然气储存技术的基本原理与特点,概述了具有工业化应用前景的高比表面积活性炭吸附剂制备的进展情况,分析了活性炭微孔结构对储气性能的影响,讨论了吸附和脱附过程热效应、天然气杂质、储存温度与压力对储气性能的影响,提出了针对主要影响因素的解决措施,展望了吸附天然气储存技术的发展趋势。     

红壤对磷的吸附特性及其影响因素研究

以红壤为吸附剂,研究了固/液吸附体系中红壤对磷的吸附特性,探讨了温度和pH对红壤吸附磷的影响.结果表明,红壤对磷的等温吸附数据与Langmuir和Freundlich方程的拟合优度较高,当温度为30℃时,红壤对磷的饱和吸附量高达1.61 mg/g,说明红壤是一种优良的磷素吸附材料;红壤对磷的吸附量在吸附初期随吸附时间急剧上升而后期趋于稳定,当磷的初始浓度为25～100 mg/L时,12 h时的吸附量均可达到平衡吸附量的90%以上;当磷的初始浓度<50 mg/L时,温度对红壤吸附磷基本无影响,但随着磷初始浓度的升高,温度对红壤吸附磷的影响渐趋明显;在所检测的试验体系中,pH值为4～8时对红壤吸附磷无明显影响.     

多孔水泥石合成滤料的制备及其污水吸附除磷试验研究

以普通硅酸盐水泥为主要原料,经反应釜高温蒸汽养护制备出多孔水泥石合成滤料。通过正交实验得到最优工艺组合条件为水固比 0.25,成孔剂/水泥=0.3,反应釜内蒸养恒温温度为180 ℃,恒温时间为4 h。采用最优条件制备的多孔水泥石合成滤料进行污水除磷试验,考察了pH值、投加量及初始磷浓度对多孔水泥石合成滤料除磷的影响。结果发现,在实验条件下,滤料对浓度5~10 mg·L -1的含磷废水的去除率都在95.3%以上,最高达99.8%;废水浓度为50 mg·L -1,pH在中性条件下,每100 mL投加2.5 g滤料,磷去除率最高达89.6%。由吸附动力学过程分析可知,该滤料除磷吸附速率特性与准二级动力学模型拟合且吸附速率由颗粒内部扩散速率控制。     

Preparation of layered double hydroxides using boron mud and red mud industrial wastes and adsorption mechanism to phosphate

Phosphate removal was important for wastewater treatment, and adsorption was an efficient treatment process. In this study, the layered double hydroxide adsorbent (BR‐LDH), which was prepared under alkali conditions using industrial residues boron mud and red mud, was used to adsorb the phosphate. The prepared BR‐LDH was characterised by X‐ray diffraction, Scanning electron microscopy, Energy‐dispersive X‐ray spectroscopy, and Thermo‐gravimetric‐differential thermal analysis. Adsorption experiments were carried out as a function of dosage, contact time, temperature and initial pH of phosphate solution. The removal ratio of phosphate onto OBR‐LDH reached 93%. The adsorption data showed a good compliance with the pseudo‐second‐order kinetic model. In addition, the mineral composition, the functional groups, the valence of elements and zeta potentials of OBR‐LDH before and after adsorption were used to analyse the adsorption mechanism. The result of real wastewater suggested that OBR‐LDH was excellent adsorbent for phosphorus removal from actual wastewater.     

Development of polymer-based nanosized hydrated ferric oxides (HFOs) for enhanced phosphate removal from waste effluents

Phosphate originated from industrial effluents is one of the key factors responsible for eutrophication of the receiving waterways especially in the developing countries such as China. In the current study we proposed a novel process to immobilize nanoparticulate hydrated ferric oxide (HFO) within a macroporous anion exchange resin D-201, and obtained a hybrid adsorbent (HFO-201) for enhanced phosphate removal from aqueous system. The resulting HFO-201 possesses two types of adsorption sites for phosphate removal, the ammonium groups bound to the D-201 matrix and the loaded HFO nanoparticles. The coexisting sulfate anion strongly competes for ammonium groups, which bind phosphate through electrostatic interaction. However, it does not pose any noticeable effect on phosphate adsorption by the loaded HFO nanoparticles, which is driven by the formation of the inner-sphere complexes. Batch adsorption experiments also indicated that HFO-201 exhibits a little higher capacity for phosphate than the commercially available phosphate-specific adsorbent ArsenX^np, which possesses similar structure of HFO-201 and is produced by another patented technique. Fixed-bed column tests indicate that phosphate retention by HFO-201 from the synthetic waters results in the significant decrease of P from 2 mg/L to less than 0.01 mg/L, with the treatment capacity of ∼700 bed volume (BV) per run, while that for D-201 was less than 200 BV under otherwise identical conditions. Such satisfactory performance of the hybrid adsorbent is mainly attributed to the specific affinity of HFO toward phosphate as well as the Donnan membrane effect exerted by the anion exchanger support D-201. Moreover, the exhausted HFO-201 was amenable to efficient in situ regeneration with a binary NaOH-NaCl solution for repeated use without any significant capacity loss. Similar satisfactory results were also observed by using a phosphate-containing industrial effluent as the feeding solution.     

Preparation and evaluation of a novel Fe-Mn binary oxide adsorbent for effective arsenite removal

Arsenite (As(III)) is more toxic and more difficult to remove from water than arsenate (As(V)). As there is no simple treatment for the efficient removal of As(III), an oxidation step is always necessary to achieve higher removal. However, this leads to a complicated operation and is not cost-effective. To overcome these disadvantage, a novel Fe-Mn binary oxide material which combined the oxidation property of manganese dioxide and the high adsorption features to As(V) of iron oxides, were developed from low cost materials using a simultaneous oxidation and coprecipitation method. The adsorbent was characterized by BET surface areas measurement, powder XRD, SEM, and XPS. The results showed that prepared Fe-Mn binary oxide with a high surface area (265 m2 g(-1)) was amorphous. Iron and manganese existed mainly in the oxidation state +III and IV, respectively. Laboratory experiments were carried out to investigate adsorption kinetics, adsorption capacity of the adsorbent and the effect of solution pH values on arsenic removal. Batch experimental results showed that the adsorbent could completely oxidize As(III) to As(V) and was effective for both As(V) and As(III) removal, particularly the As(III). The maximal adsorption capacities of As(V) and As(III) were 0.93 mmol g(-1) and 1.77 mmol g(-1), respectively. The results compare favorably with those obtained using other adsorbent. The effects of anions such as SO4(2-), PO4(3-), SiO3(2-), CO3(2-) and humic acid (HA), which possibly exist in natural water, on As(III) removal were also investigated. The results indicated that phosphate was the greatest competitor with arsenic for adsorptive sites on the adsorbent. The presence of sulfate and HA had no significant effect on arsenic removal. The high uptake capability of the Fe-Mn binary oxide makes it potentially attractive adsorbent for the removal of As(III) from aqueous solution.     

树脂基水合氧化铈复合材料深度去除污水中磷酸盐

通过"前驱体导入-原位沉积"的工艺路线,将水合氧化铈(HCO)纳米颗粒负载入强碱阴离子交换树脂(SAE)孔道内,制得复合纳米吸附剂HCO@SAE并用于污水中磷酸盐的深度去除。试验结果表明:与其母体材料SAE、粉末活性炭(PAC)和大孔吸附树脂XAD-4相比,HCO@SAE具有最佳的磷酸盐吸附性能。溶液pH值对HCO@SAE吸附磷酸盐的性能有较大影响,且在中性条件下可获得最大的磷酸盐吸附量(30.96 mgP/g)。得益于负载HCO纳米颗粒对磷酸盐的专属内配位络合作用,HCO@SAE能够在共存高浓度竞争离子的条件下实现对磷酸盐的选择性吸附。采用NaOH-NaCl混合溶液作为脱附剂可实现对吸附饱和HCO@SAE的高效再生,再生后吸附性能保持稳定,从而实现多批次循环吸附操作。     

Enhanced trace phosphate removal from water by zirconium(IV) loaded fibrous adsorbent

This study was investigated for the trace phosphate removal at high feed flow rate by ligand exchange fibrous adsorbent. The zirconium(IV) loaded bifunctional fibers containing both phosphonate and sulfonate were used as a highly selective ligand exchange adsorbent for trace phosphate removal from water. The precursory fiber of the bifunctional fibers was co-grafted by polymerization of chloromethylstyrene and styrene onto polyethylene coated polypropylene fiber and then bifunctional fibers were prepared by Arbusov reaction followed by phosphorylation and sulfonation. Phosphate adsorption experimental work was carried out in column approach. Phosphate adsorption increased with decreasing the pH of feed solutions. An increase in the feeds flow rate brings a decrease in both breakthrough capacity and total adsorption. The effect of competing anions on phosphate adsorption systems was investigated. The experimental findings reveal that the phosphate adsorption was not affected in the presence of competing anions such as chloride and sulfate despite the enhancement of the breakthrough points and total adsorption. Due to high selectivity to phosphate species, low concentration level of phosphate (0.22 mg/L) was removed at high feed flow rate of 450 h⁻¹ in space velocity. The adsorbed phosphate on the Zr(IV) loaded fibrous column was quantitatively eluted with 0.1 M NaOH solution and then the column was regenerated by 0.5 M H₂SO₄ for the next adsorption operation. During many adsorption-elution-regeneration cycles, no measurable Zr(IV) was found in the column effluents. Therefore, the Zr(IV) loaded bifunctional fibrous adsorbent is to be an effective means to treat wastewater to prevent eutrophication in the receiving water bodies for long time without any deterioration.     

新生态水合氧化铁去除水中磷酸根的效能研究

以新生态水合氧化铁(FHIO,由高铁酸钾和氯化亚铁配制)为混凝剂,考察了对水中磷酸根的处理效能,以及有机物浓度、pH、温度、浊度等参数对其去除磷酸根的影响。通过对原水pH和浊度变化的分析,发现FHIO的水解过程不同于普通铁盐,可形成细小、比表面积大、吸附能力强的铁氧体。在投加氯化铁进行混凝时,随着投量(6、7、8mg/L)的增加,对磷酸根的去除率分别达到了54%、59%、70%。而在相同的总铁投量下,FHIO对磷酸根的去除率分别提高了11%、13%、9%。水中有机物浓度的增加,对FHIO的除磷效果有一定的影响,这是因为有机物在一定程度上抑制了Fe(Ⅱ)的氧化,间接地影响了FHIO的生成,从而降低了除磷效果。在较低温度、pH和浊度时,FHIO对磷酸根的去除效果明显优于单独铁盐的,这是由于FHIO的无定形状态和细小的颗粒度决定其受这些因素的影响较小。     

Arsenic removal from aqueous solutions by adsorption on magnetite nanoparticles

Magnetite nanoparticles were used to treat arsenic‐contaminated water. Because of their large surface area, these particles have an affinity for heavy metals by adsorbing them from a liquid phase. The results of the study showed that the maximum arsenic adsorption occurred at pH 2, with a value of approximately 3.70 mg/g for both As(III) and As(V) when the initial concentration of both arsenic species was maintained at 2 mg/L. The study showed that, apart from pH, the removal of arsenic from contaminated water also depends on the contact time, the initial concentration of arsenic, the phosphate concentration in the water and the adsorbent concentration. The results suggest that arsenic adsorption involved the formation of weak arsenic–iron oxide complexes at the magnetite surface. At a fixed adsorbent (magnetite nanoparticles) concentration of 0.4 g/L, percent arsenic removal decreased with increasing phosphate concentration. Magnetite nanoparticles removed <50% of arsenic from water containing >6 mg/L phosphate. In this case, an optimum design for achieving high arsenic removal by magnetite nanoparticles may be required.     

Removal of mercury(II) from aqueous solutions and chlor-alkali industry wastewater using 2-mercaptobenzimidazole-clay

The 2-mercaptobenzimidazole loaded natural clay was prepared for the removal of Hg(II) from aqueous media. Adsorption of the metal ions from aqueous solution as a function of solution concentration, agitation time, pH, temperature, ionic strength, particle size of the adsorbent and adsorbent dose was studied. The adsorption process follows a pseudo-second-order kinetics. The rate constants as a function of initial concentration and temperature were given. The adsorption of Hg(II) increased with increasing pH and reached a plateau value in the pH range 4.0-8.0. The removal of Hg(II) was found to be >99% at an initial concentration of 50 mg/l. Mercury(II) uptake was found to increase with ionic strength and temperature. Further, the adsorption of Hg(II) increased with increasing adsorbent dose and decrease with adsorbent particle size. Sorption data analysis was carried out using Langmuir and modified Langmuir isotherms for the uptake of metal ion in an initial concentration range of 50-1,000 mg/l. The significance of the two linear relationships obtained by plotting the data according to the conventional Langmuir equation is discussed in terms of the binding energies of the two population sites involved which have a widely differing affinity for Hg(II) ions. Thermodynamic parameters such as changes of free energy, enthalpy, and entropy were calculated to predict the nature of adsorption. It was found that the values of isosteric heat of adsorption were varied with surface loading. The chlor-alkali industry wastewater samples were treated by MBI-clay to demonstrate its efficiency in removing Hg(II) from wastewater.     

Removal of phosphate by layered double hydroxides containing iron

Iron-based layered double hydroxides (M2+(a)Fe3+(b) (OH)2(a+b) CO3(2-) b/2mH2O) were synthesized. Removal of phosphate by the compounds was studied from the viewpoint of buffering pH effect of the compounds and buffering capacity of solution. The compounds released metal cations (Mg2+, Ca2 , Fe3+) and/or their hydroxides responding to various water environments due to their buffering pH function. The released cations and/or hydroxides worked effectively as coagulants for the phosphate removal. The removal of phosphate depended on the buffering capacity of the solution that is the function of the solution pH and the concentration of phosphate. The removal of phosphate from the solution with small buffering capacity followed a Langmuir-type isotherm. The removal of phosphate from the solution with larger buffering capacity was largely increased. The removal of phosphate by the compounds was analyzed based on the model describing the buffering pH effect of the compounds from which the amount of released cations (CB) can be determined. The removal was well correlated with the amount of dissolution of the compounds, CB. The mechanism of phosphate removal was examined based on the removal efficiency (mol of removed phosphate/mol of released alkali). The efficiencies showed below one in the solution with large buffering capacity and above one in the solution with small buffering capacity. The efficiency below one showed the removal of phosphate through coagulation by the released metal cations and hydroxides. The successful removal of dilute phosphate (0.2mg P/l) from the drain water was also demonstrated.     

Removal of phosphorus from aqueous solution using alumized red mud

Treated red mud, the solid residue from bauxite processing, was found to adsorb phosphorus from dilute aqueous solution effectively. Experiments were carried out in aqueous as well as buffer media to obtain the optimum conditions like contact time, pH, adsorbent dose, adsorbate concentration, temperature etc. The pH value of 4.5 was found to be optimum for maximum removal. The equilibrium was attained within 60 mins. Lower adsorbent dose and higher initial phosphorus concentration favoured higher loading capacity. The adsorption process followed Freundlich isotherm and Lagergren equations and they followed first order rate kinetics. The effect of different anions on phosphorus removal could be explained on the basis of the changing affinity of anions for the surface and their relative concentrations.