污泥活性炭的制备及其对溶液中Cr6+的吸附

以城市污水厂剩余污泥为原料，采用ZnCl2作活化剂，热解制备污泥活性炭。实验结果表明，制备污泥活性炭的最佳条件热解温度为550℃，ZnCl2溶液浓度为3mol／L，ZnCl2溶液体积与污泥质量比（mL／g）为2．5：1，热解时间为25min。用所制备的污泥活性炭吸附溶液中的Cr6＋最佳吸附条件为：吸附时间90min，Cr6＋初始质量浓度50mg／L，污泥活性炭加入量0．2g，溶液pH2，在此条件下，Cr6＋去除率达99．9％。污泥活性炭对溶液中Cr6＋的吸附等温线属于I型，等温吸附方程可用Langmuir模型和Freundlich模型来拟合。     

用黄姜皂素残渣制备活性炭

以黄姜皂素残渣为原料,用ZnCl2为活化剂制备活性炭,研究了活化温度、活化剂浓度、液固比、活化时间对活性炭吸附性能的影响。在活化温度600℃、活化时间90min、ZnCl2质量分数40％、液固比（质量比）4条件下。制备的活性炭碘吸附值为933mg/g,苯酚吸附值为139mg/g,亚甲基蓝脱色力为150mL/g,性能优于对比的商业颗粒活性炭。     

甘蔗叶活性炭的制备

以H3PO4为活化剂制备甘蔗叶活性炭,采用正交实验对活性炭的制备工艺进行了优化,并研究了活性炭对含铬废水的吸附和再生性能.实验结果表明:在H3PO4体积分数为15％、H2SO4体积分数为6％、HC1体积分数为3％、活化温度为723 K、活化时间为0.58 h的工艺条件下,活性炭得率为35.07％,碘吸附值为1 207 mg/g.活性炭对Cr(Ⅵ)的最大平衡吸附量为30.89 mg/g,HNO3再生后对Cr(Ⅵ)的最大平衡吸附量为39.48 mg/g;再生效率最高达87.41％,经3次再生,活性炭的再生效率仍能维持在80％以上.     

焦粉活性炭的制备及其应用

用废弃焦粉制备焦粉活性炭，通过正交实验考察了各种因素对焦粉活性炭性能的影响。实验结果表明：在活化时间80min、活化温度900℃、碱炭比（氢氧化钾与废弃焦粉的质量比）4、废弃焦粉粒径小于0．05mm的最佳条件下，制备的焦粉活性炭的亚甲基蓝吸附值为304．8mg／g，产率为35．6％；废弃焦粉的活化是活化剂刻蚀其颗粒形成丰富孔结构的氧化还原反应过程；用最佳条件下制备的焦粉活性炭处理质量浓度为60mg／t．的模拟含Cr^6＋废水，在废水pH为3—4、焦粉活性炭加入量为4g/L、吸附时间为50min的条件下，Cr^6＋去除率达93．2％。     

氯化锌活化法制备甘蔗渣活性炭吸附剂

采用氯化锌活化法制备了甘蔗渣活性炭吸附剂，并考察了活化剂氯化锌溶液浓度、活化温度和活化时间对吸附剂吸附性能的影响。实验结果表明，氯化锌活化法制备甘蔗渣活性炭吸附剂的最佳工艺条件为：活化温度800℃、氯化锌溶液质量浓度190g／L、活化时间60min。所得甘蔗渣活性炭吸附剂的得率为30．3％，碘吸附值为1070mg／g，亚甲基蓝吸附值（以0．1g吸附剂吸附的亚甲基蓝体积计）为15．0mL，达到了GB／T13803．2—1999《木质净水用活性炭》一级品标准（碘吸附值1000mg／g，亚甲基蓝吸附值9mL）。     

中孔活性炭对水溶液中Cr3+的吸附

采用模板法和氢氧化钾化学活化法制备出不同中孔率的中孔活性炭并用于水中Cr3+的静态吸附,探讨了中孔活性炭吸附Cr3+的影响因素.实验结果表明,当溶液pH为6.0、吸附温度为50℃、吸附时间为120min、活性炭加入量为2.0g/L以及活性炭中孔率为80.0％～90.0％时.中孔活性炭对溶液中Cr3+的去除率达到98.5％.分别采用Langmuir和Freundlich方程拟合活性炭对Cr3+吸附的等温线,发现Langmuir等温吸附模型对活性炭吸附Cr3+拟合程度更好.活性炭中孔率的增大有利于提高Cr3+的平衡吸附量,但同时还受到活性炭表面酸总量的影响.吸附Cr3+前、后活性炭的FTIR谱图表明,Cr3+与活性炭表面含氧官能团发生了离子交换反应.     

豆渣对水中Cd2+和Zn2+的吸附

研究了新型生物吸附剂豆渣对水中Cd^2＋和Zn^2＋的吸附机制和吸附能力；分析了吸附时间、溶液pH、豆渣质量浓度和重金属离子质量浓度对重金属离子去除效果的影响。豆渣对Cd^2＋和Zn^2＋的吸附过程符合Langmuir等温吸附方程。在Cd^2＋溶液和Zn^2＋溶液的pH分别为6．0和7．0、质量浓度为50mg／L、豆渣质量浓度为10．0g／L的条件下，吸附12h，Cd^2＋和Zn^2＋的去除率分别为96．O％和89．4％。通过Langmuir吸附等温线模拟，得出豆渣对Cd^2＋和Zn^2＋的最大吸附量分别为19．61mg／g和11．11mg／g。     

重金属在碱渣层中的分布及形态研究

采用自制动态吸附柱考察了碱渣层对重金属离子(Cu2+、Zn2+和Cd2+)的吸附截留能力.实验结果表明,在高浓度和高水力负荷条件下,碱渣对Cu2+、Zn2+和Cd2+的最大吸附量分别可达194.451,24.245,11.036 mg/g,穿透时间均达 60 h 以上,饱和吸附时间超过 80 h.通过 Testier ...     

脂肪磺酸基阳离子交换树脂对Cr3+的吸附和解吸性能

研究了脂肪磺酸基阳离子交换树脂（简称树脂）对Cr3＋的吸附和解吸性能。在溶液初始Cr3＋质量浓度为250m∥L、吸附温度为25℃、溶液pH为5的条件下，树脂对Cr3＋的吸附量最大。Cr3＋质量浓度在实验范围内，等温吸附过程均符合Langmuir和Freundlich方程，最大吸附量为18．6208mg／g。树脂对Cr3＋的吸附在吸附时间为180min时趋于平衡，且吸附为液膜扩散控制。随吸附温度的升高（10～55℃），树脂对Cr3＋的吸附量略有增加。用质量分数为5％的HCl溶液可将吸附在树脂上的Cr3＋解吸，解吸率近100％，且重复5次吸附和解吸过程，树脂对Cr3＋的吸附量基本保持不变。     

污泥碳化制备活性炭

采用城市污水厂二沉池湿污泥为原料,添加活化剂直接活化制备污泥活性炭。实验结果表明,最优的制备条件:0.5mol/L的KOH为活化剂,浸泡时间为20h,碳化温度为600℃,升温速率为15℃/h,碳化时间为1h。在此条件下所制备的污泥活性炭吸附性能最好,孔体积为0.19cm3/g,比表面积为737.61m2/g,碘值为879.62mg/g,性能优于普通颗粒活性炭。采用最优条件下制备的污泥活性炭吸附处理电镀废水,总铬去除率为69.46%,铅去除率为78.88%,镍去除率为60.34%。     

钛铁矿造孔核桃壳基活性炭的制备及其吸附性能

以核桃壳为原料，钛铁矿为造孔剂，制备钛铁矿造孔核桃壳基活性炭。实验结果表明：在氯化锌浓度为3mol/L、碳化时间为40min、碳化温度为400℃、钛铁矿加入量为5%的条件下，制得的钛铁矿造孔核桃壳基活性炭对苯酚、碱性品红、Pb²⁺的吸附量分别达到了156.80，181.35，35.84mg/g，比核桃壳活性炭分别提高了25.84%，18.59%，19.10%；钛铁矿作为造孔剂制备活性炭，可以降低碳化温度和缩短碳化时间，且对活性炭中孔的形成起促进作用，有利于对大分子物质和重金属的吸附去除。     

Acidic bioleaching of heavy metals from sewage sludge

The overall objective of this study was to evaluate the use of controlled bio-acidification prior to land application as a decontamination process to remove heavy metals from sludge. The sulfur-oxidizing bacteria were naturally available in the sludge samples and were activated by providing sulfur and aeration at 28°C–30°C. Activation resulted in bio-acidification to pH 2 within 5–11 days. Successive inoculation of fresh sludges with 5% acidified samples reduced the acidification time to 2–3 days in most samples. Bio-acidification resulted in dissolving significant quantities of heavy metals from all sludge types tested. The maximum solubilization results were: 86%–97% for Ni; 48%–98% for Pb; 26%–71% for Cr; 18%–91% for Zn; 16%–90% for Cu; 7%–60% for Cd. Limited metal solubilization results were observed in the various control samples that accompanied the bio-acidified samples. The leaching results in the control samples were limited to 2%–19% for Ni, 0%–7% for Pb, 0%–5% for Cr, 0.3%–4% for Zn, 0.2%–4% for Cu and 0%–3% for Cd. The results confirmed that Ni and Pb were the easiest metals to dissolve from the various sludge types. On the other hand, the lowest solubilization results were observed for Cu and Cd, and moderate solubilization results were achieved for Cr. The bio-acidification process resulted in moderate gains in terms of improving the suitability of tested sludges for land application. Received: April 19, 1999 / Accepted: November 4, 1999     

次氯酸钠废液活化法制备柚子皮活性炭

以柚子皮为原料,采用次氯酸钠废液活化法制备了柚子皮活性炭,通过正交实验优化了制备条件,并运用SEM、FTIR和XRD技术对活性炭产品进行了表征。实验结果表明:制备柚子皮活性炭的最佳工艺条件为炭化温度350℃、次氯酸钠废液含量25%(φ)、次氯酸钠废液活化时间25 min、高温活化温度650℃、高温活化时间60 min;最佳条件下,柚子皮活性炭的产率为31.88%、碘吸附值为854 mg/g、亚甲基蓝吸附值为216.9 mg/g。表征结果显示:活化后的柚子皮炭具有更大的孔体积、更有序的孔径排布和更发达的孔隙结构;柚子皮活性炭表面存在大量的含氧基团;柚子皮活性炭的石墨化度为61.32%,具有较高的稳定性。     

亚临界湿式氧化法脱除含油污泥中的重金属

采用亚临界湿式氧化法及金属络合剂协同亚临界湿式氧化法去除含油污泥中的重金属,考察了去除效果,优化了反应条件,并探讨了脱除重金属的含量上限。实验结果表明:在1 L反应釜内加入200 g含油污泥,在反应温度200℃、反应时间60 min、液固比(去离子水与含油污泥的质量比)0.30的优化条件下,Cu和Zn的去除率分别可达67.3%和22.0%;加入金属络合剂后,各重金属的去除率均有明显提高;在金属络合剂加入量为0.05mol/L的优化条件下,应用金属络合剂协同亚临界湿式氧化法可将2.5倍于CJ/T 309—2009《城镇污水处理厂污泥处置农用泥质》B级标准的重金属含量降至标准范围内。     

Fixation and partitioning of heavy metals in slag after incineration of sewage sludge

Fixation of heavy metals in the slag produced during incineration of sewage sludge will reduce emission of the metals to the atmosphere and make the incineration process more environmentally friendly. The effects of incineration conditions (incineration temperature 500-1100°C, furnace residence time 0-60min, mass fraction of water in the sludge 0-75%) on the fixation rates and species partitioning of Cd, Pb, Cr, Cu, Zn, Mn and Ni in slag were investigated. When the incineration temperature was increased from 500 to 1100°C, the fixation rate of Cd decreased from 87% to 49%, while the fixation rates of Cu and Mn were stable. The maximum fixation rates for Pb and Zn and for Ni and Cr were reached at 900 and 1100°C, respectively. The fixation rates of Cu, Ni, Cd, Cr and Zn decreased as the residence time increased. With a 20min residence time, the fixation rates of Pb and Mn were low. The maximum fixation rates of Ni, Mn, Zn, Cu and Cr were achieved when the mass fraction of water in the sludge was 55%. The fixation rate of Cd decreased as the water mass fraction increased, while the fixation rate of Pb increased. Partitioning analysis of the metals contained in the slag showed that increasing the incineration temperature and residence time promoted complete oxidation of the metals. This reduced the non-residual fractions of the metals, which would lower the bioavailability of the metals. The mass fraction of water in the sludge had little effect on the partitioning of the metals. Correlation analysis indicated that the fixation rates of heavy metals in the sludge and the forms of heavy metals in the incinerator slag could be controlled by optimization of the incineration conditions. These results show how the bioavailability of the metals can be reduced for environmentally friendly disposal of the incinerator slag.     

Experimental study on flue gas purifying of MSW incineration using in-pipe jet adsorption techniques

This paper presents the experimental research process and results about flue gas purifying of municipal solid wastes (MSW) incineration using in-pipe jet adsorption techniques. MSW incineration was carried out in a fluidized bed test rig, and the flue gas purifying was carried out in an in-pipe jet adsorption test rig. The experimental results are as follows: when the feedstock of activated carbon is 1.6g/Nm(3), the desulfurization efficiency is 83%, the denitrification efficiency is 41%, and the dechlorination efficiency is 27%. The order of purifying effect of the three kinds of adsorbents on acidic gases from MSW incineration is activated carbon>activated bauxite>kaolin. Comparison of adsorption capabilities of the three kinds of adsorbents to heavy metals shows that activated carbon is the best additive to remove Cd, Pb and Cu, kaolin is inferior, and activated bauxite is the worst one. However, activated bauxite is the best additive to remove Hg, and it can remove Cd effectively. PAHs in fly ash are dominated by three-, four-, and five-ringed PAHs, and PAHs in the flue gas mainly include three- and four-ringed PAHs. When the injected quantity of additive is constant, the order of cleaning effect on PAHs is kaolin>activated carbon>activated bauxite. These three kinds of adsorbents have different purifying effects on acidic gases, heavy metals and PAHs in the flue gas from MSW incineration. In general, activated carbon has a better adsorption capability.     

Characteristic of heavy metals in biochar derived from sewage sludge

This study investigates the characteristic of heavy metals (Pb, Zn, Cu, Cd, Cr, Ni and As) in biochar derived from sewage sludge at different pyrolysis temperatures (300, 400, 500, 600 and 700 °C). The heavy metal concentrations, chemical speciation distribution, leaching toxicity, and bio-available contents were investigated using ICP-OES after microwave digestion, a sequential extraction procedure recommended by the Community Bureau of Reference (BCR), an improved nitric acid–sulphuric acid method, and diethylenetriamine pentaacetic acid (DTPA) extraction method, respectively. The results showed that a great percentage of the heavy metals remained in biochar, the concentrations of heavy metals in biochar (except Cd in B7) were higher than that in sludge, and the enrichment of the heavy metals in biochar enhanced with the pyrolysis temperature. Although the effect of pyrolysis temperature on the chemical speciation distribution, the leaching toxicity and the bio-available contents of heavy metals in biochar was inconsistent, the potential risk of biochar on soil and groundwater contamination was lower than sewage sludge.     

Limitations for heavy metal release during thermo-chemical treatment of sewage sludge ash

Phosphate recycling from sewage sludge can be achieved by heavy metal removal from sewage sludge ash (SSA) producing a fertilizer product: mixing SSA with chloride and treating this mixture (eventually after granulation) in a rotary kiln at 1000 ± 100 °C leads to the formation of volatile heavy metal compounds that evaporate and to P-phases with high bio-availability. Due to economical and ecological reasons, it is necessary to reduce the energy consumption of this technology. Generally, fluidized bed reactors are characterized by high heat and mass transfer and thus promise the saving of energy. Therefore, a rotary reactor and a fluidized bed reactor (both laboratory-scale and operated in batch mode) are used for the treatment of granulates containing SSA and CaCl₂. Treatment temperature, residence time and - in case of the fluidized bed reactor - superficial velocity are varied between 800 and 900 °C, 10 and 30 min and 3.4 and 4.6 m s⁻¹. Cd and Pb can be removed well (>95 %) in all experiments. Cu removal ranges from 25% to 84%, for Zn 75-90% are realized. The amount of heavy metals removed increases with increasing temperature and residence time which is most pronounced for Cu.In the pellet, three major reactions occur: formation of HCl and Cl₂ from CaCl₂; diffusion and reaction of these gases with heavy metal compounds; side reactions from heavy metal compounds with matrix material. Although, heat and mass transfer are higher in the fluidized bed reactor, Pb and Zn removal is slightly better in the rotary reactor. This is due the accelerated migration of formed HCl and Cl₂ out of the pellets into the reactor atmosphere. Cu is apparently limited by the diffusion of its chloride thus the removal is higher in the fluidized bed unit.     

Synthesis of Chitosan@activated Carbon Beads with Abundant Amino Groups for Capture of Cu(II) and Cd(II) from Aqueous Solutions

In this study, chitosan and bio-based activated carbon obtained from sugarcane bagasse biowaste were used for the synthesis of efficient sorbent for Cu(II) and Cd(II) ion via precipitation method. The prepared material was enriched with amino groups through grafting tetraethylenepentamine and tested for heavy metal remediation from water samples. The influence of pH was investigated showing optimum sorption at pH 6 for Cu(II) and Cd(II). Sorption tests, explained by means of the most common sorption models, evidenced that the best performances were reached pointing out the promising application of the prepared sorbent for water purification treatments: Uptake kinetics are relatively fast: the equilibrium was reached within 140 min; and the kinetic profiles were preferentially fitted by the pseudo-second order rate equation. Sorption isotherms are fitted by Langmuir equation. The sorbent showed high metal ion sorption capacity with negligible influence of ion strength. The maximum sorption capacities reached 3.44 and 2.38 mmol g^??1 for Cu(II) and Cd(II), respectively at 298 K. Thermodynamic parameters were evaluated through variation of temperature. The sorption is unfavorable at elevated temperatures. Metal ions were successfully desorbed using 1 M HNO₃ solution.     

Poultry litter-based activated carbon for removing heavy metal ions in water

Utilization of poultry litter as a precursor material to manufacture activated carbon for treating heavy metal-contaminated water is a value-added strategy for recycling the organic waste. Batch adsorption experiments were conducted to investigate kinetics, isotherms, and capacity of poultry litter-based activated carbon for removing heavy metal ions in water. It was revealed that poultry litter-based activated carbon possessed significantly higher adsorption affinity and capacity for heavy metals than commercial activated carbons derived from bituminous coal and coconut shell. Adsorption of metal ions onto poultry litter-based carbon was rapid and followed Sigmoidal Chapman patterns as a function of contact time. Adsorption isotherms could be described by different models such as Langmuir and Freundlich equations, depending on the metal species and the coexistence of other metal ions. Potentially 404 mmol of Cu²⁺, 945 mmol of Pb²⁺, 236 mmol of Zn²⁺, and 250–300 mmol of Cd²⁺ would be adsorbed per kg of poultry litter-derived activated carbon. Releases of nutrients and metal ions from litter-derived carbon did not pose secondary water contamination risks. The study suggests that poultry litter can be utilized as a precursor material for economically manufacturing granular activated carbon that is to be used in wastewater treatment for removing heavy metals.