纳米Fe3O4磁性粒子的制备及吸附性能研究

采用共沉淀法制备了纳米Fe3O4磁性粒子。应用透射电子显微镜（TEM）、扫描电子显微镜（SEM）、X-射线衍射仪（XRD）和振动样品磁强计（VSM）等对纳米磁性粒子的粒径、结构、形貌、磁性能进行了表征，进行了磁分离沉降性能和腐殖酸吸附去除实验研究。结果表明：在未添加任何分散剂的条件下，制得的纳米Fe3O4磁性粒子主要呈球状，平均粒径约11nm，为典型的反尖晶石结构；饱和磁化强度、矫顽力和剩余磁化强度分别为73．10emu／g、159．2A／m和0．41emu／g；磁分离沉降速度为重力场的50倍；纳米Fe3O4磁性粒子对腐殖酸的吸附符合Langmuir型吸附等温线。     

流化催化裂化中DeSOx催化剂的研究

用共沉淀法合成了三个系列的ＤｅＳＯｘ催化剂：铜类催化剂、铈类催化剂、铜铈类催化剂。模拟流化催化裂化（ＦＣＣ）条件，分别考察了催化剂的组成、水热处理、反应温度、体系中氧气浓度为ＳＯｘ吸附容量的影响，研究了催化剂吸附ＳＯｘ后的再生性能，同时将合成催化剂与工业催化剂（ＩＮＴＥＲＣＡＴ公司的ＤｅＳＯｘ催化剂）的ＤｅＳＯｘ性能进行了比较。结果表明，随 反应温度５的升高，催化剂的ＳＯｘ吸附容量出现一极大值；水     

沉淀分离富集-电感耦合等离子原子发射光谱测定土壤中可溶态稀土元素

研究电感耦合等离子体原子发射光谱测定土壤中微量可溶态稀土元素的方法。在适宜的ｐＨ＝１０－１１条件下,以ＭｇＣｌ２为载体沉淀分离除去浸提液中的大部分基体杂质如Ｎａ＾＋,Ａｃ＾－,Ｃａ＾２＋,Ｍｇ＾２＋等,有效地消除了这些杂质的干扰,提高了测定方法的准确度;同时,待测可溶态稀土元素被沉淀集,样品中总稀土及单一稀土加标回收率为８８％－１１０％,样品测定结果满意,方法简便快速。     

纳米零价铁颗粒除磷反应机理

从溶液化学与固相表征两方面对纳米零价铁(NZVI)去除水中磷酸根(PO3-4)的机理进行初步探究。分别研究不同初始p H值、溶解氧(DO)对NZVI除磷效果的影响,结果表明,酸性环境(p H为3.0~7.0)有利于NZVI除磷,且初始p H值越低,磷去除率越高;好氧环境较厌氧环境更利于磷的去除,DO8.0 mg/L时对磷酸根的去除率是厌氧条件(DO0.1 mg/L)下的2倍。采用Na OH对反应后含磷NZVI进行解析,发现磷解析率不到30%,说明吸附并非NZVI除磷惟一作用机理。微米铁、NZVI和Ca(OH)2等7种不同去除材料中以Ca(OH)2的共沉淀作用去除率最大(99.9%),NZVI次之(87.2%),表明NZVI除磷机理中还存在共沉淀作用。采用多种固相表征手段对NZVI除磷前后进行分析:扫描电子显微镜(SEM)显示反应后出现不规则颗粒;X射线衍射(XRD)表明Fe3(PO4)2是主要反应产物;X射线光电子能谱(XPS)分析未发现磷被还原成低价态。研究表明,NZVI可有效去除水中磷酸根,主要去除机理包括:NZVI对磷酸根的吸附作用、NZVI在水中腐蚀产生的Fe2+离子对磷酸根的化学沉淀作用及铁氢氧化物与磷酸根的共沉淀作用。     

纳米Fe_3O_4磁性粒子的制备及吸附性能研究

采用共沉淀法制备了纳米Fe3O4磁性粒子。应用透射电子显微镜(TEM)、扫描电子显微镜(SEM)、X-射线衍射仪(XRD)和振动样品磁强计(VSM)等对纳米磁性粒子的粒径、结构、形貌、磁性能进行了表征,进行了磁分离沉降性能和腐殖酸吸附去除实验研究。结果表明:在未添加任何分散剂的条件下,制得的纳米Fe3O4磁性粒子主要呈球状,平均粒径约11 nm,为典型的反尖晶石结构;饱和磁化强度、矫顽力和剩余磁化强度分别为73.10 emu/g、159.2 A/m和0.41 emu/g;磁分离沉降速度为重力场的50倍;纳米Fe3O4磁性粒子对腐殖酸的吸附符合Langmuir型吸附等温线。     

Preparation of calcium oxalate—bromopyrogallol red inclusion sorbent and application to treatment of cationic dye and heavy metal wastewaters

Background, aim, and scope  Dye pollutants are a major class of environmental contaminants. Over 100,000 dyes have been synthesized worldwide and more than 700,000 tons are produced annually and over 5% are discharged into aquatic environments. The adsorption or sorption is one of the most efficient methods to remove dye and heavy metal pollutants from wastewater. However, most of the present sorbents often bear some disadvantages, e.g. low sorption capacity, difficult separation of spoil, complex reproduction, or secondary pollution. Development of novel sorbents that can overcome these limitations is desirable. Materials and methods  On the basis of the chemical coprecipitation of calcium oxalate (CaC₂O₄), bromopyrogallol red (BPR) was embedded during the growing of CaC₂O₄ particles. The ternary C₂O₄ ^2––BPR–Ca²⁺ sorbent was yielded by the centrifugation. Its composition was determined by spectrophotometry and AAS, and its structure and morphology were characterized by powder X-ray diffraction (XRD), laser particle-size analysis, and scanning electron microscopy (SEM). The adsorption of ethyl violet (EV) and heavy metals, e.g. Cu(II), Cd(II), Ni(II), Zn(II), and Pb(II) were carried out and their removal rate determined by spectrophotometry and ICP-OES. The adsorption performance of the sorbent was compared with powder activated carbon. The Langmuir isothermal model was applied to fit the embedment of BPR and adsorption of EV. Results  The saturation number of BPR binding to CaC₂O₄ reached 0.0105 mol/mol and the adsorption constant of the complex was 4.70 × 10⁵ M^–1. Over 80% of the sorbent particles are between 0.7 and 1.02 μm, formed by the aggregation of the global CaC₂O₄/BPR inclusion grains of 30–50 nm size. Such a material was found to adsorb cationic dyes selectively and sensitively. Ethyl violet (EV) was used to investigate the adsorption mechanism of the material. One BPR molecule may just bind with one EV molecule. The CaC₂O₄/BPR inclusion material adsorbed EV over two times more efficiently than the activated carbon. The adsorption of EV on the CaC₂O₄/BPR inclusion sorbent was complete in only 5 min and the sedimentation complete in 1 h. However, those of EV onto activated carbon took more than 1.5 and 5 h, respectively. The treatment of methylene blue and malachite green dye wastewaters indicated that only 0.4% of the sorbent adsorbed over 80% of color substances. Besides, the material can also adsorb heavy metals by complexation with BPR. Over 90% of Pb²⁺, and approximately 50% of Cd²⁺ and Cu²⁺, were removed in a high Zn²⁺-electroplating wastewater when 3% of the material was added. Eighty-six percent of Cu²⁺, and 60% of Ni²⁺ and Cd²⁺, were removed in a high Cd²⁺-electroplating wastewater. Discussion  The embedment of BPR into CaC₂O₄ particles responded to the Langmuir isothermal adsorption. As the affinity ligand of Ca²⁺, BPR with sulfonic groups may be adsorbed into the temporary electric double layer during the growing of CaC₂O₄ particles. Immediately, C₂O₄ ^2– captured the Ca²⁺ to form the CaC₂O₄ outer enclosed sphere. Thus, BPR may be released and embedded as a sandwich between CaC₂O₄ layers. The adsorption of EV on the sorbent obeyed the Langmuir isothermal equation and adsorption is mainly due to the ion-pair attraction between EV and BPR. Different from the inclusion sorbent, the activated carbon depended on the specific surface area to adsorb organic substances. Therefore, the adsorption capacity, equilibrium, and sedimentation time of the sorbent are much better than activated carbon. The interaction of heavy metals with the inclusion sorbent responded to their coordination. Conclusions  By characterizing the C₂O₄ ^2––BPR–Ca²⁺ inclusion material using various modern instruments, the ternary in situ embedment particle, [(CaC₂O₄)₉₅(BPR)] _n ^2n–, an electronegative, micron-sized adsorbent was synthesized. It is selective, rapid, and highly effective for adsorbing cationic dyes and heavy metals. Moreover, the adsorption is hardly subject to the impact of electrolytes. Recommendations and perspectives  The present work provides a simple and valuable method for preparing the highly effective adsorbent. If a concentrated BPR wastewater was reused as the inclusion reactant, the sorbent will be low cost. By selecting the inclusion ligand with a special structure, we may prepare some particular functional materials to recover the valuable substances from seriously polluted wastewaters. The recommended method will play a significant role in development of advanced adsorption materials. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

硫酸生产中废水治理工艺的改进

采用ＮａＣｌＯ氧化共沉淀脱砷工艺处理硫酸废水，在ＮａＣｌＯ投加量１２００ｍｇ／Ｌ、铁砷比３．０、氧化终点ｐＨ３．５、聚丙烯酰胺投加量１５ｍｇ／Ｌ的条件下，处理后出水中砷含量降至１．０６ｍｇ／Ｌ，再经第二级中和沉淀后可达国家排放标准。此工艺能使砷富集于沉渣中，达到可回收的水平，此外还可大大减少含砷废渣的产生量。     

沉积物中氧化物结合态镉对芦苇的生物有效性研究：氧化物种类、结合形式、老化的影响

沉积物中重金属的生物有效性在很大程度上取决于其赋存形态.选用沉积物中2种典型氢氧化物矿物:氢氧化铁和氢氧化铝,以水培法和矿物结合态Cd为培养介质,以芦苇为受试植物,研究环境中吸附和共沉淀态Cd生物有效性差别,并探究老化过程对生物有效性的影响.经过13 d的培养,发现2种结合形式的Cd均可被芦苇富集,不同处理体系中富集强度不同,根中富集量为9.1~37.8 mg.kg-1;地上部分富集量为0~10.0 mg.kg-1.其中,结合在Fe0.5Al0.5(OH)3矿物上的Cd的生物有效性最大,其次是Fe(OH)3和老化的Fe0.5Al0.5(OH)3,富集量最少的是老化的Fe(OH)3的处理.采用2种低分子量有机酸对Cd进行解吸实验,Cd的解吸规律与芦苇对Cd的富集规律一致.因此,共沉淀处理降低了Cd的富集,矿物的理化性质决定了含铝矿物对Cd的结合较差,老化作用抑制了吸附态Cd的富集,有机酸解吸实验也验证了不同形态Cd生物有效性的差异.     

含铀硼镁铁矿硫酸浸出液除铀的研究

辽宁省翁泉沟含铀硼镁铁矿的硫酸浸出液主要成分是Ｈ３ＢＯ３和ＭｇＳＯ５,并含有少量Ｆｅ＾３＋和ＵＯ＾２＋２。本研究用ＭｇＯ调节溶液的ｐＨ值,进行了含铁与不含铁７种溶液的除铀试验。当溶液不含Ｆｅ＾３＋时,靠ＵＯ＾２＋２自身沉淀后,溶液中Ｕ浓度高于硫酸出液中的Ｕ含量,无法将铀除去。     

改进铁氧体共沉淀法去除污泥浸出液中的铜锌

采用改进铁氧体共沉淀法，用石灰乳溶液作中和剂，从污泥浸出液中去除铜、锌。实验结果表明，在混合液．pH为8．9、反应温度为室温、反应时间为1h、FeCl3和FeSO4初始浓度分别为0．1068mol／L和0．0534mol／L、n（Fe^3＋）：[n（Cu^2＋）＋n（Zn^2＋）]=10的最佳工艺条件下，浸出液中铜去除率为94．5％，锌去除率为98．0％。