高比表面积羟基氧化铁的脱砷性能

利用羟基氧化铁的吸附特性可以有效脱除水体中的重金属,考察在不同条件下的脱砷效果。采用浆态床脱除法进行评价实验,主要考察废液砷含量、p H、温度、羟基氧化铁浓度和震荡时间等对脱砷率的影响。结果表明,废液砷含量和p H对脱砷率影响较小,时间、温度及羟基氧化铁浓度对脱砷率影响较大,羟基氧化铁浓度为影响脱砷效果的主要因素,整体来看,脱除率较高。在羟基氧化铁浓度为150 mg·m L-1、震荡时间1 h和温度50℃条件下,可将初始砷含量176.00 mg·L-1的废水降至砷含量为5.46 mg·L-1。     

壳聚糖对酸性品红的吸附研究

探讨了壳聚糖吸附酸性品红的影响因素。单因素试验优选了吸附时间、壳聚糖用量、p H值、酸性品红溶液初始浓度、温度及搅拌速率等。在此基础上进行了四因素三水平的正交试验,结果表明,壳聚糖吸附酸性品红的最佳工艺条件为:酸性品红溶液的初始质量浓度为30 mg/L、p H=4,壳聚糖投加量为0.008 g/mL,吸附时间为80 min,此时壳聚糖对酸性品红溶液的吸附脱色率达到96.8%。     

普鲁兰复合吸附剂对As的去除研究

以重金属砷为主要研究对象,将普鲁兰和氧化镁用溶胶凝胶法制得普鲁兰复合吸附剂,探究了普鲁兰复合吸附剂的最佳制备条件,并研究了其对As的吸附去除性能。试验表明:在氧化镁与普鲁兰的质量配比为3∶2,搅拌时间为12 h,烘干温度为65℃,煅烧温度为400℃和煅烧时间为1 h的条件下,可以得到具有良好除砷性能的复合吸附剂。同时考察了初始砷浓度、初始pH、吸附温度及吸附时间等因素对该吸附剂吸附砷的影响。结果表明:普鲁兰复合吸附剂能较好的处理As质量浓度为50～200 mg/L,pH为3～11的含砷废水,且在室温下吸附反应5 h吸附剂达到饱和,其吸附量可达到136. 190mg/g。     

新型纳米复合吸附剂对地下水中氟离子的去除效果研究

为了有效去除含氟地下水中的F^-,以Ca(NO₃)₂、(NH₄)₂HPO₄和柠檬酸为主要原料,通过水热合成反应,制备了一种新型纳米复合吸附剂Nam-1,并通过吸附实验考察了吸附剂加量、反应温度、反应时间、溶液p H值、振荡速度和地下水中F^-初始浓度对F^-去除率的影响。结果表明,吸附剂Nam-1的加量越大、反应温度越高、反应时间越长以及振荡速度越大,F^-去除率相对就越高,而溶液p H值和初始F^-浓度越大,F^-去除率相对就越低。在F^-初始浓度均为10mg·L^-1的条件下,吸附实验的最佳参数为：新型纳米复合吸附剂Nam-1的加量为2g·L^-1、反应温度为30℃、反应时间为120min、溶液p H值为7、振荡速度为160r·min^-1,在最佳实验参数下的F^-     

柚子皮粉末对铜离子的吸附

采用柚子皮粉末吸附水中Cu2+。通过单因素实验考察了温度、p H、Cu2+的初始浓度、吸附时间和投加量对吸附效果的影响。最佳吸附条件为:温度为室温,p H为6.0,Cu2+的初始浓度为20 mg/L,吸附时间为20 min,投加量为0.15 g/50 m L。在该条件下,吸附率能够达到60%以上。热力学和动力学试验表明吸附符合Langmuir等温吸附模式和准二级动力学模型。     

插层水滑石对水中Cd2+吸附性能研究

制备了Zn Al-NO3-LDH和Zn Al-EGTA-LDH。考察了Zn Al-NO3-LDH和Zn Al-EGTA-LDH在不同温度、初始浓度、不同p H值、不同时间条件下对废水中Cd2+的吸附量,结果显示Zn Al-EGTA-LDH对Cd2+的吸附量大于Zn Al-NO3-LDH;在无其他干扰离子,温度为40℃,p H值=5,Cd2+的初始浓度为70mg·L-1,吸附时间为3 h,对Cd2+最大静态吸附量为187.51 mg/g。     

改性硫酸铁铵丝瓜络生物炭对砷的吸附行为研究

在生态环境保护日益获得重视的背景下,加强砷污染治理成为迫切的工作。采用硫酸铁铵改性丝瓜络生物质炭,研究材料的砷吸附行为,对吸附时间、生物质炭投放量、砷溶液初始p H值和生物质炭制备温度几个方面进行了优化。结果表明,随着吸附时间延长和生物质炭投放量增加,吸附效果变好;砷溶液初始p H值增大,吸附效果先上升后下降,pH2.0时吸附率最高;在吸附时间、砷溶液初始p H值、生物质炭投放量和生物质炭制备温度相同的情况下,硫酸铁铵改性后的丝瓜络生物质炭具有更优的砷吸附效果。     

污泥活性炭对含酚废水的吸附性能研究

文章利用泉州市污水处理厂生化池污泥为主要原料制备污泥活性炭,研究其对含酚废水的吸附效果,考察了污泥活性炭添加量、振荡时间、反应温度、p H、初始浓度对含酚废水去除率的影响。结果表明,污泥活性炭的碘值为530 mg/g,吸附含酚废水的最佳条件为:污泥活性炭添加量为15 g/L、吸附时间为70 min、p H为6、温度为25℃、初始浓度为10 mg/L对苯酚溶液去除率最佳可达97.9%,符合Frenndlich吸附模型。     

花生油饼对Cr(Ⅵ)的吸附研究

以花生油饼作为吸附剂,对Cr(VI)进行吸附处理。通过单因素实验,探究了溶液初始质量浓度、吸附剂投加量、吸附时间、搅拌速率及溶液p H等因素对吸附性能的影响。在此基础上进行了正交试验,其结果表明花生油饼吸附Cr(VI)的最佳吸附条件为:100 m L初始质量浓度为15 mg/L的模拟含铬废水,吸附剂用量为1.0g,p H为2.0,搅拌速率为240 r/min,吸附时间为120 min。其中p H和吸附时间是影响去除率的两个重要因素,在该吸附条件下,花生油饼对Cr(VI)的去除率为97%,Cr(VI)的剩余质量浓度为0.45 mg/L,小于《污水综合排放标准》(GB8978—1996)中第一类污染物的排放限定值。等温吸附实验表明,花生油饼对Cr(VI)的吸附用弗罗因德利希吸附等温方程拟合更好。     

臭葱石法处理含砷废水

本文以锌冶炼过程的含砷废水为研究对象,研究了溶液初始p H值、温度、反应时间对沉砷过程的影响。实验结果表明,升高温度、提高初始pH值、延长反应时间,均能有效提高沉砷率。在初始Fe/As摩尔比为1.5、初始p H=4、温度90℃、反应时间5h的条件下,溶液的沉砷率和沉铁率分别为91.3%和79.1%,并析出了臭葱石晶体。     

Removal of As(V) Using an Iron-Impregnated Ion Exchange Bead

The ability of an iron-impregnated ion exchange bead (PWX5) to remove As(V) from ground water was investigated. The effects of particle size, solution pH, As(V) concentration, competition, adsorbent concentration, temperature, iron content, and iron accessibility on removal kinetics and/or equilibrium were determined. PWX5's performance was compared to other iron-based adsorbents, primarily Bayoxide® E-33 (E-33), a granular ferric oxide, for arsenic removal performance. All of the factors cited impacted either the amount of As(V) adsorbed or the rate of adsorption. Stirred batch reactor data showed the rate of adsorption increased as particle size decreased and bottle point isotherm data showed As(V) adsorption maximum capacity increased with higher initial adsorbate concentration. The presence of phosphate and silicate reduced the amount of As(V) adsorbed as did a pH > 7.0. PWX5 is durable, rather homogeneous in size and effective at removing As(V). It is a viable alternative to E-33 which has a wider size distribution and wears more easily.     

Arsenic adsorption using copper (II) oxide nanoparticles

Arsenic poisoning is a major problem in today's life. To reduce its concentration in drinking water, different metal based compounds were explored as arsenic adsorbents. In the present study, copper (II) oxide nanoparticles were prepared by thermal refluxing technique and used as an adsorbent for arsenic removal from water. Characterization of the adsorbent using TEM, BET, XRD and FTIR implied that the prepared adsorbent was in nano size and had excellent adsorption behavior with surface area of 52.11 m²/g. Systematic adsorption experiments were carried out with different process parameters such as contact time, adsorbent mass, pH, temperature and stirring speed and found that copper (II) oxide had very good efficiency towards arsenic adsorption. Thermodynamic parameters and adsorption kinetics were studied in detailed to know the nature and mechanism of adsorption. Results showed that the adsorption process followed pseudo second order kinetic and endothermic behavior. Adsorption equilibrium was studied with Langmuir and Freundlich isotherm models. The adsorption process followed Langmuir isotherm with an adsorption capacity of 1086.2 μg/g. A regeneration study was proposed in order to reuse the adsorbent for better economy of the process. Finally, a process design calculation is reported to know the amount of adsorbent required for efficient removal of arsenic from aqueous medium.     

氢氧化铁胶体对砷吸附行为的初步研究

研究了pH值、铁与砷的量比和初始砷浓度等因素对用氢氧化铁胶体吸附去除砷的影响,确定了最佳吸附条件。研究结果表明,在初始As(Ⅴ)或As(Ⅲ)浓度为0.1mmol/L条件下,去除As(Ⅴ)的最佳pH值为4～8,去除As(Ⅲ)最佳pH值为6～9;在初始As(Ⅴ)浓度为0.5mmol/L条件下,去除As(Ⅴ)的最佳pH值为5～7,吸附后溶液中砷含量低于0.5mg/L,达到了《污水综合排放标准(GB8978-1996)》中工业废水最高容许排放总砷浓度一级标准。通过等温吸附试验的研究,得出了As(Ⅴ)和As(Ⅲ)的饱和吸附容量分别为0.4971mol/kg和0.3068mol/kg。     

Effects of temperature and phosphoric acid addition on the solubility of iron phosphate dihydrate in aqueous solutions

As important controlling factors for the synthesis of iron phosphate materials by liquid-phase precipitation, the solubilities of iron phosphate dihydrate were systematically measured at H_3PO_4 concentrations from 1.13 wt%to 10.7 wt%, temperature from 298.15 to 363.15 K, and atmosphere pressure in this work. The solubility was found to increase 5 orders of magnitude or more with increasing the concentration of phosphoric acid, and decrease 1 to 2 orders of magnitude with increasing the equilibrium temperature. The phosphoric acid addition and temperature were found to affect the solubility of iron phosphate dihydrate by the formation or dissociation of coordination species, which could further accelerate the phase transformation from the amorphous iron phosphate dihydrate to orthorhombic iron phosphate dehydrate by dissolution–recrystallization mechanism.The high dependences of the solubility of iron phosphate materials on H_3PO_4 concentration and temperature were also well predicted by calibration equations, which are meaningful for quantitatively understanding the precipitation process and sequential crystalline structure transformation and pursuing a rational strategy for synthesizing specific iron phosphate materials.     

磷在涂铁浮石上的吸附性能

通过对天然浮石进行涂铁改性,研究了涂铁浮石吸附水溶液中磷的热力学和动力学. 结果表明,Langmuir等温吸附方程比Freundlich等温吸附方程更能准确地描述涂铁浮石对磷的吸附,粒径为0.63~1.2 mm的涂铁浮石,298 K时对磷的最大吸附量为0.245 mg/g. 准二级动力学模型比准一级动力学模型和颗粒内扩散模型更能准确地描述涂铁浮石吸附除磷的动力学过程. 通过计算不同温度下的热力学参数DG0, DH0和DS0,证实该吸附为自发的吸热过程. SEM和EDAX分析表明磷吸附在涂铁浮石表面上.     

负载铁离子活性炭除砷的研究进展

砷污染是一个严重的世界问题,在其诸多的去除方法中,负载铁离子活性炭兼顾了活性炭和混凝沉淀的优势,可高效去除砷离子.作者对负载铁离子活性炭的制备方法、影响砷去除率的主要因素和吸附模型的研究现状进行了详细评述,其中负载铁离子活性炭的孔径结构、表面性质,负载铁离子的形貌、分布、种类和质量等决定着其吸附容量；通过调节搅拌时间、...     

沸石用于高温凝结水除铁的实验研究

针对高温凝结水温度较高,需要降温处理的特点,研究了一种新的高温水除铁方法,采用斜发沸石替代传统的树脂材料除去高温凝结水中的铁离子.考察了pH、溶液浓度、沸石用量对吸附的影响.在95℃高温条件下,用2 g活化沸石处理1 mg/L的铁溶液,40 min可达到吸附平衡,使铁离子浓度降到0.3 mg/L以下,研究结果表明活化斜发沸石是一种适合工业热能动力系统高温凝结水除铁处理的理想吸附材料.     

Dispersion of FeOOH on Chitosan Matrix for Simultaneous Removal of As(III) and As(V) from Drinking Water

Bio-inorganic chitosan based spherical shaped beads were prepared by dispersing rod-shaped FeOOH nanoparticles into a chitosan matrix for the removal of pure As(III) and As(V) from aqueous media, such as drinking water. A homogeneous mixture of chitosan and ferric nitrate, ferric chloride was prepared respectively with or without oxalic acid. The mixture was added dropwise in to a NaOH bath, where iron salts reacted with NaOH to form FeOOH particles. The scanning electron microscopy (SEM) showed that rod shaped FeOOH particles were distributed homogenously in the chitosan matrix. Diffuse reflective UV-vis (DRUV) spectra revealed that hydrated iron oxide formed a complex with functional groups in chitosan. Adsorption of As(III) and As(V) on different iron salt based bead was found to be pH dependent. The bead prepared from iron nitrate showed better performance for arsenic removal from aqueous solution over the bead that was prepared using iron chloride salt. The bead prepared using chitosan and iron-FeOOH is known as a chitosan-iron oxyhydroxide (CFOH) bead. The CFOH beads were found to be more efficient in removing As(III) from the solution compared to As(V). The adsorption of As(III) and As(V) from aqueous solution on CFOH beads was studied under equilibrium conditions in the concentration range of 1 mg/L to 50 mg/L in the presence of 0.05 M NaNO₃ at pH 6.5 and 298 K temperature. The maximum adsorption capacity of the CFOH bead was found to be 5.4 mg/g for As(V) and 7.2 mg/g for As(III) using the Langmuir equation. The presence of sulphate, phosphate, and silicate in aqueous solution had no effects on adsorption of either As(III) or As(V) on CFOH beads but decreased significantly at pH> 8.     

Adsorption and desorption characteristics of arsenic onto ceria nanoparticles

The rapid increase in the use of engineered nanoparticles [ENPs] has resulted in an increasing concern over the potential impacts of ENPs on the environmental and human health. ENPs tend to adsorb a large variety of toxic chemicals when they are emitted into the environment, which may enhance the toxicity of ENPs and/or adsorbed chemicals. The study was aimed to investigate the adsorption and desorption behaviors of arsenic on ceria NPs in aqueous solution using batch technique. Results show that the adsorption behavior of arsenic on ceria NPs was strongly dependent on pH and independent of ionic strength, indicating that the electrostatic effect on the adsorption of these elements was relatively not important compared to surface chemical reactions. The adsorption isotherms fitted very well to both the Langmuir and Freundlich models. The thermodynamic parameters (ΔH ⁰ , ΔS ⁰ , and ΔG ⁰ ) for the adsorption of arsenic were determined at three different temperatures of 283, 303, and 323 K. The adsorption reaction was endothermic, and the process of adsorption was favored at high temperature. The desorption data showed that desorption hysteresis occurred at the initial concentration studied. High adsorption capacity of arsenic on ceria NPs suggests that the synergistic effects of ceria NPs and arsenic on the environmental systems may exist when they are released into the environment.