污泥基生物炭的制备及其对Hg~(2+)的吸附

在添加乙酸钾的条件下将污泥低温热解制备出污泥基生物炭,并将其用于溶液中Hg~(2+)的吸附,考察了Hg~(2+)吸附效果的影响因素,并对吸附机理进行了分析。表征结果显示:热解对污泥有一定的造孔作用,而乙酸钾对孔隙结构的形成影响更大。实验结果表明:在吸附温度为25℃、溶液p H为6、初始Hg~(2+)质量浓度为15 mg/L、污泥基生物炭投加量为6 g/L的条件下,吸附24 h时的Hg~(2+)去除率达97.08%;污泥基生物炭对Hg~(2+)的吸附过程符合Langmuir等温吸附模型,吸附行为符合Lagergren准二级动力学方程。     

MgO/SiO_2纳米复合材料同步吸附亚甲基蓝和Cu~(2+)

采用化学沉积法合成了MgO/SiO_2纳米复合材料,通过扫描电子显微镜和X射线能谱分析(SEM-EDX)、X射线衍射(XRD)、Zeta电位仪、FTIR等方法对其进行了表征。研究了MgO/SiO_2对亚甲基蓝(MB)和Cu~(2+)的吸附行为及同步吸附效果。表征结果表明:MgO/SiO_2为褶皱、凸起的球形形貌;MgO成功负载在SiO_2表面。实验结果表明:MgO/SiO_2对MB和Cu~(2+)的吸附符合准二级动力学模型和Langmuir等温吸附模型,MB和Cu~(2+)的饱和吸附量分别为83.72 mg/g和208.70 mg/g;MB和Cu~(2+)的同步吸附在MgO/SiO_2表面存在竞争关系;在溶液体积为30m L、MgO/SiO_2加入量为10 mg、MB质量浓度为10 mg/L或Cu~(2+)质量浓度为100 mg/L、吸附温度为25℃、吸附时间为24 h、初始溶液pH为4.00、解吸时间为4 h的条件下,MgO/SiO_2第1次吸附MB和Cu~(2+)的去除率分别为92.8%和90.1%,第5次吸附的去除率分别为59.6%和57.4%。     

Recycling of Tannery (chrome) sludge into sludge biochar (SB) /TiO2 nanocomposite via chemical activation through hydrothermal pre-treatment

Journal of Material Cycles and Waste Management - The preparation of biochar from Tannery (chrome) sludge has gained recent attention among many scientists globally. Hydrothermal pre-treatment...     

Characterization of coal gangue and coal gangue-based sodalite and their adsorption properties for Cd2+ ion and methylene blue from aqueous solution

Journal of Material Cycles and Waste Management - Synthesis and development of high-efficiency and low-cost adsorbents for treating of the wastewater containing heavy metal ions and/or dyes has...     

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.     

Adsorption characteristics of Cu2+ and Zn2+ from aqueous solution using carbonized food waste

The aim of the present study was to analytically provide adsorption characteristics of Cu²⁺ and Zn²⁺ using carbonized food waste (CFW); more specifically, batch tests were conducted using various concentrations of metal ions, contact times, and initial pH levels in an attempt to understand the adsorption removal of heavy metal ions in aqueous solution at concentrations ranging between 50 and 800 mg/l. The results confirmed that the adsorption equilibrium was established within a maximum of 80 min, and the maximum concentrations for adsorption of Cu²⁺ and Zn²⁺ were 28.3 and 23.5 mg/g, respectively. These adsorption levels indicate that CFW has better performance than many other adsorbents. In experiments using different pH conditions, the applicability to acid wastewater was found to be high, and an excellent adsorption removal ratio of 75%–90% was observed under acid conditions at pH 2–4. Furthermore, as the adsorption time increased, the calcium component in the CFW began to leach into the aqueous solution and raise the pH, accordingly causing the removal of heavy metal ions partially as a result of precipitation. When our results were analyzed using the Langmuir model and the Freundlich model for isothermal adsorptivity, the activity of CFW in this study was shown to be more consistent with the former; the adsorption speed of Cu²⁺ and Zn²⁺ according to a pseudosecond-order reaction model was found to be very fast for an initial concentration of not more than 100 mg/l. In a test in which an attempt was made to compare adsorption capacity values obtained from the experiments in this study with the aforementioned three models, the pseudosecond-order reaction model was found to provide results closest to the actual values.     

The mild hydrothermal synthesis of hydrogrossular from coal ash

In this study, an attempt was made to synthesize hydrogrossular, a group of garnet minerals, under hydrothermal conditions at temperatures below 180°C, using coal ash, which is the solid waste from thermal power plants, as a starting material. A single phase corresponding to hydrogrossular was found at around 120°C, and the hydrogrossular coexisted with 11-Å tobermorite above 140°C. The hydrogrossular phase decreased with increasing reaction temperature, while that of 11-Å tobermorite increased concurrently. The physicochemical properties of the hydrogrossular obtained from the hydrothermal synthesis was characterized by X-ray diffraction thermogravimetry/differential thermal, analysis, scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray fluorescence spectroscopy. Received: September 4, 2000 / Accepted: March 7, 2001     

Adsorption of Pb2+ by insolubilized humic acid extracted from sewage sludge

Journal of Material Cycles and Waste Management - This study used excess sludge from a sewage treatment plant as raw material to extract humic acid (HA) and explore the ability of HA to adsorb Pb2+...     

改性多孔淀粉对Cu2+的捕集性能

以玉米淀粉为原料,采用糖化酶和α-淀粉酶复合酶解制成多孔淀粉,多孔淀粉经交联、间接醚化、胺化、黄原酸酯化反应得到二硫代氨基甲酸基改性多孔淀粉(DTCPS)重金属捕集剂.研究了DTCPS对Cu2+的捕集性能.实验结果表明:制得的多孔淀粉的比表面积为1.264 5 m2/g,比玉米淀粉的比表面积增大了138.5%;制得的多孔淀粉是一种中孔淀粉;Cu2+溶液pH为1-5时,DTCPS的Cu2+饱和捕集量均较高;Cu2+初始质量浓度为0～70 mg/L时,DTCPS对Cu2+的捕集性能很好,溶液中Cu2+的剩余质量浓度低于0.12 mg/L,Cu2+的去除率达99%以上.DTCPS对Cu2+的捕集性能明显优于二硫代氨基甲酸基改性淀粉(DTCS).     

改性生物炭对Ni~(2+)和Cu~(2+)的吸附

以废弃松木屑为原料制备了生物炭,采用六亚甲基四胺(HMTA)和/或CO2对其进行改性,并将其用于水中Ni2+和Cu2+的吸附。表征结果显示,以HMTA和CO2共同改性的生物炭BC1的表面积最小但表面含氧官能团含量最高。实验结果表明:生物炭经改性后,其吸附性能明显提高,且以BC1为最优;在不调节溶液p H、初始重金属离子质量浓度为50 mg/L、吸附剂加入量分别为2.0 g/L和1.0 g/L、吸附时间分别为360 min和240 min的优化条件下,BC1对Ni2+和Cu2+的去除率分别达到99.81%和95.88%;改性生物炭对Ni2+和Cu2+的吸附过程可以用Langmuir等温吸附模型来描述,而其吸附动力学具有拟二级动力学方程特征。     

Hydrogen-rich gas production from sorption-enhanced sludge gasification using CaO-based biochar derived from crab shell as a CO2 sorbent

Journal of Material Cycles and Waste Management - A CaO-based biochar (CSC) prepared from waste crab shell was used as a low-cost CO2 sorbent to enhance sludge steam gasification for H2-rich gas...     

Size-fractionation and characterization of landfill leachate and the improvement of Cu2+ adsorption capacity in soil and aged refuse

Leachate was collected from an anaerobic lagoon at Shanghai Laogang refuse landfill, the largest landfill in China, and the sample was separated into six fractions using micro-filtration membranes, followed by ultra-filtration membranes. Several parameters of the samples were measured, including chemical oxygen demand (COD), total organic carbon (TOC), total solids (TS), pH, total phosphate (TP), total nitrogen (TN), fixed solids (FS), NH4+, orthophosphate, color, turbidity, and conductivity. These parameters were then quantitatively correlated with the molecular weight cutoff of the membrane used. Organic matter in the dissolved fraction (MW<1kDa) predominated in the leachate, accounting for 65% of TOC. Thermal infrared spectroscopy was used to characterize the filter residues. Asymmetric and symmetric stretching of methyl and methylene groups, and of functional groups containing nitrogen and oxygen atoms, were observed. In addition, the ability of two different samples to adsorb heavy metals was tested. Cu2+ was chosen as the representative heavy metal in this study, and the samples were soil; aged refuse, which had spent 8 years in a conventional sanitary landfill; and samples of soil and aged refuse treated for 48h with leachate in the ratio of 5g of sample per 50ml of leachate. Cu2+ uptake by the raw soil was approximately 4.60microg/g, while uptake by the leachate-contacted soil and leachate-contacted aged refuse were 5.66 and 5.11microg/g, respectively. These results show that the organic matter in the leachate enhanced the capacity of aqueous solutions to adsorb Cu2+.     

改性多壁碳纳米管对Pb2+、Cu2+和Co2+的竞争吸附研究

采用HNO3改性的多壁碳纳米管（MWCNTs）分别对Pb^2＋、Cu^2＋和Co^2＋进行吸附,并在含3种离子的混合溶液中进行竞争吸附。单一离子吸附结果表明,在室温、pH=5的条件下,MWCNTs对单一离子的饱和吸附量分别为：Pb^2＋91mg／g;Cu^2＋24mg／g;Co^2＋12mg／g。竞争吸附结果表明,在溶液中各金属离子的平衡质量浓度均为30mg／L时,MWCNTs对Pb^2＋、Cu^2＋和Co^2＋的平衡吸附量分别为43,15,6mg／g。MWCNTs对3种金属离子的吸附选择性大小顺序为：Pb^2＋〉Cu^2＋〉Co^2＋分别用Langmuir和Frundlich模型对单一吸附和竞争吸附进行拟合,结果表明,该吸附过程更符合Langmuir模型。     

尿素基纤维的制备及对水中Cu2+和Cd2+的吸附

以棉纤维为原料,经氯化和取代反应,制得尿素基纤维并用于水中Cu^2＋和Cd^2＋的吸附,考察了各种因素对吸附效果的影响。尿素基纤维对Cu^2＋和Cd^2＋的吸附可用Langmuir等温吸附方程描述,吸附过程可看成单层吸附。较佳吸附条件：重金属离子溶液pH为5,流量为7mL／min。用过的尿素基纤维经2mol／L的盐酸洗脱再生后,对Cu^2＋的吸附、解吸、再吸附的性能良好,可重复使用。     

丙烯酸柱撑类水滑石的制备及其对Cu2+的吸附性能

以Zn-Al-NO3--类水滑石为前体,采用返混沉淀法制备了丙烯酸柱撑类水滑石,将其用于吸附废水中的Cu2+.实验结果表明:当初始Cu2+质量浓度为80 mg/L、丙烯酸柱撑类水滑石加入量为40 g/L、废水pH为6、吸附时间为2.0 h时,丙烯酸柱撑类水滑石对Cu2+有较好的吸附效果,在此条件下废水中Cu2+的吸附率高达95.31％;丙烯酸柱撑类水滑石对Cu2+的吸附符合Freundlich等温吸附模型.     

Cu2+-Mn2+-H2O2体系催化氧化降解罗丹明B

研究了Cu2＋-Mn2＋-H2O2体系催化氧化降解染料罗丹明B的效果。实验结果表明,Cu2＋-Mn2＋-H2O2体系的罗丹明B降解率比H2O2体系、Mn2＋-H2O2体系和Cu2＋-H2O2体系有显著提高,反应120rain后罗丹明B降解率接近100％。对于Cu2＋-Mn2＋-H2O2体系,最佳罗丹明B降解条件：溶液pH为5,反应温度为45℃,质量浓度为10mg／L的罗丹明B溶液体积100mL,浓度为0．01mol／L的硫酸铜溶液加入量5．0mL,浓度为0．01moVL的硫酸锰溶液加入量3．0mL,体积分数为30％的H2O2溶液加入量1．5mL。在此条件下罗丹明B降解的反应速率常数最大,为0．04228min-1,其拟合相关系数为0．99912。罗丹明B降解符合一级动力学模型。     

HW型高分子捕集剂处理含铅铜废水

采用聚丙烯酰胺、NH：OH·HCI和NaOH反应合成了HW型高分子捕集剂（简称捕集剂）,考察了捕集剂对Ph^2＋,Cu^2＋质量浓度分别为100mg／L的废水的处理效果。研究结果表明：在含Ph^2＋废水pH为6．5～7．0、n（捕集剂）：n（Pb^2＋）：1．6、反应时间为50min的最佳条件下,Ph^2＋去除率达100．00％;在含Cu^2＋废水pH为5．5～6．0、n（捕集剂）：n（Cu^2＋）=1．0、反应时间为60min的最佳条件下,Cu^2＋去除率达99．73％。对Ph^2＋,Cu^2＋质量浓度分别为50mg／L的混合废水,n（捕集剂）：n（Pb^2＋＋Cu^2＋）=1．2时,对Ph^2＋,Cu^2＋的去除率均达到99％以上。捕集剂去除pb^2＋,Cu^2＋的机理为羟肟酸基团与Ph^2＋,Cu^2＋反应生成稳定的螯合物。与中和法沉淀物相比,捕集剂与Ph^2＋,Cu^2＋反应生成的螯合物的Ph^2＋,Cu^2＋浸出量小,具有更好的环境安全性。     

水性油墨废水絮凝污泥制备吸附剂及阳离子染料的吸附

以水性油墨废水絮凝污泥为原料、采用一步炭化活化法制备了吸附剂,并将其用于阳离子蓝X-GRRL溶液(300 mg/L)的吸附处理。考察了吸附剂投加量、吸附时间、吸附温度和吸附pH对吸附效果的影响,并对吸附动力学进行了探讨。结果表明:所制得吸附剂的总孔体积为0.5 cm~3/g,平均孔径为7.12 nm;在吸附剂投加量0.6g/L、吸附时间420 min、吸附温度25℃、吸附pH 5.4的条件下,吸附量高达486.21 mg/g,脱色率达97.24%;该吸附剂对于阳离子蓝X-GRRL的吸附过程可用准二级动力学模型和颗粒内扩散效应模型很好地描述。     

竹炭对废水中Cu2+的吸附

探讨了竹炭粒径、加入量、溶液 pH、吸附时间、Cu2+初始质量浓度等因素对竹炭吸附 Cu2+效果的影响.实验结果表明:竹炭对废水中Cu2+有很好的吸附效果,当竹炭粒径小于0.15 mm、加入量为 16 g/L、溶液 pH 为 6.0、Cu2+初始质量浓度 25 mg/L、吸附时间为 1.5 h 时,竹炭对 Cu2+的去...