利用牡蛎壳和废玻璃粉制备废水除磷吸附材料的研究

以牡蛎壳和废玻璃粉为主要原料制备了空心管状型体废水除磷材料,探讨了在500～650℃不同预烧温度、不同样品配方及与废水接触不同时间下样品的废水除磷效果,从而选择最佳制备条件.采用XRD及SEM表征样品的微观结构及组成,采用磷钼蓝分光光度法测定废水中磷的含量.结果表明,含废玻璃粉20%、牡蛎壳80%的样品在600℃煅烧时除磷效果最好,12天后除磷率达到99%;XRD分析显示此时样品主要由3种晶相组成,CaCO3、SiO2和CaO,说明在此温度下牡蛎壳中的部分CaCO3已经分解为CaO.     

水滑石除磷的吸附动力学研究

采用共沉淀法制备了Mg/Al水滑石,研究了不同Mg/Al物质的量比、材料用量、不同pH条件下Mg/Al水滑石吸附除磷的动力学特征,从而对吸附速率的控制过程进行分析。结果表明水滑石对磷的吸附能较好地符合准二级动力学方程、Elovich动力学方程和内扩散模型。n(Mg)/n(Al)=3是水滑石最理想配比,水滑石投加量越大,外扩散过程越慢;一定范围内pH的升高能促进水滑石对磷吸附速率和吸附容量的提升。     

不同结构铝氧化物对磷的吸附特征

磷是影响藻类生长的重要营养元素,它在沉积物界面上的吸附是海洋环境中磷循环的重要环节,金属氧化物是吸附磷沉积物的重要活性组分之一。采用批量实验法研究不同结构的氧化铝对无机磷的吸附特征,分别使用二段一级动力学方程和Freundlich等方程对其动力学曲线和平衡吸附等温线进行定量描述,并对介质盐度、温度等影响因素进行研究。结果发现,无定型氧化铝结晶弱且比表面积大,该特点使其吸附容量大于γ-Al₂O₃,结合表面酸碱滴定的结果,可知吸附也与铝氧化物的表面酸碱性质相关。分析影响因素可知,与NaNO₃介质相比,氧化铝吸附海水中的磷受到阻滞,且随着介质离子强度增大,吸附量均呈现降低趋势;p H显著影响磷的吸附量,在pH=5左右,两种氧化铝表面对磷酸根的吸附达到最大值;温度升高,有利于吸附的进行,该吸附为吸热、自发、熵增加的过程,两种结构氧化铝的吸附热力学参数无显著差异。     

磁性Zr基MOFs材料的合成及吸附水中磷的性能研究

基于液相外延生长原理,采用自组装法合成了磁性氨基功能化MOFs材料Fe₃O₄@NH₂-UiO-6(Fe-NUiO(Zr)-005),对其进行了XRD、FTIR、SEM和BET等表征分析,研究了其在水体中对磷的吸附性能,探讨了吸附除磷的机理。结果表明,在Fe₃O₄上自组装生成了具有介孔结构的纳米磁性复合材料Fe-NUiO(Zr)-005,其比表面积大,稳定性高,该材料适应磷溶液的pH(3.0～9.0)宽,吸附效果良好,吸附过程符合Langmuir模型,饱和吸附量达71.94 mg·g^-1。材料吸附磷的平衡时间为200 min,吸附过程符合伪二级动力学方程,且受到了多种机制的影响。在实际水环境和共存离子(Cl^-、SO₄^2-和NO^-₃)中应用时,吸附剂呈现出较强的抗干扰能力,其具有较高的吸附低浓度磷的潜力。材料能够循环使用至少5次,Fe-NUiO(Zr)...     

海洋聚磷菌 Halomonas YSR-3 的除磷特性研究

用改变培养条件的方法对海洋聚磷菌Halomonas YSR-3 的生长和除磷特性进行了研究.研究结果表明,无磷培养时,该菌菌体不能生长;用磷酸钾盐作为磷源时,菌体生长较好,形成多聚磷酸盐的菌体比例较高;较适合YSR-3菌体生长和多聚磷酸盐形成的磷源是 KH2PO4,较适磷浓度为1 mmol/L.pH 的变化影响菌株的生长、多聚磷酸盐形成和除磷效果.pH 值为5时,菌体的数量几乎不增加(△OD480为0.013),体内多聚磷酸盐和培养基中磷含量变化不大;pH 值为6、7和8时,菌体生长良好(△OD480分别为1.529、1.539和1.497),95%以上的菌体内形成多聚磷酸盐,培养基中磷含量明显下降.YSR-3在不同培养基中除磷量和除磷率不同.在高磷培养基中除磷量为0.7 mmol/L(磷含量由1.84mmol/L降到1.14 mmol/L),除磷率为37.5%;在低磷培养基中除磷量为0.02 mmol/L(磷含量由0.028 mmol/L降到0.008 mmol/L),除磷率为72.2%.     

改性牡蛎壳对废水中磷吸附性能的研究

采用高温煅烧对天然牡蛎壳进行改性处理,并初步研究了天然牡蛎壳和经过不同煅烧温度处理后的牡蛎壳样品对废水中磷的吸附作用。采用TGA-DTA、XRD、SEM分别对天然牡蛎壳的热分解历程和不同温度烧结后所得的改性牡蛎壳的相组成和微观结构进行研究。结果表明:在相同的条件下,天然牡蛎壳粉对废水中磷的吸附效果较差;牡蛎壳经过650~800℃煅烧处理后,其对废水中磷的吸附性能明显提高。当煅烧温度为750℃时,牡蛎壳煅烧物对废水中磷的去除率可以达到99%。因此牡蛎壳经过750℃煅烧处理后,是一种固磷性能较好的新型钙基除磷剂。     

茭白苞叶中总黄酮提取及其体外抗氧化性能研究

运用超声波技术辅助提取茭白苞叶中的总黄酮,经正交实验得出茭白苞叶中总黄酮提取的最佳工艺参数:超声波功率700 W,温度60℃,料液比(g/mL)1∶60,乙醇质量分数浓度为60%,提取时间为35 min,茭白苞叶中总黄酮最大提取率为1.127%.采用抗坏血酸作为对照,全面测定了茭白苞叶总黄酮对超氧阴离子自由基、羟基自由基、DPPH自由基的清除率,以及还原能力、抗脂质过氧化活性和对食用油脂的抗氧化性的影响,结果表明,白苞叶中的总黄酮是一种有开发价值的天然抗氧化剂.     

氧化镁/聚醚砜复合膜吸附材料的制备与除氟性能研究

以活性氧化镁和聚醚砜(PES)为原料,采用共混法制备了氧化镁/聚醚砜复合膜吸附材料;用扫描式电子显微镜(SEM)和ASAP2020型比表面及孔径分析仪进行了表征,并研究了复合膜对氟离子的吸附性能。SEM结果表明,氧化镁颗粒在聚合物膜中均匀镶嵌分布,提高了膜的孔隙率。比表面积与孔径分析表明复合膜的比表面积约为颗粒氧化镁的1/3。复合膜对水中氟离子的吸附在60min后基本达到平衡;30cm2的复合膜(厚度为200μm)可以处理50mL氟离子溶液(质量浓度为5mg/L),使其符合饮用水含氟标准(<1mg/L);吸附量随初始浓度的增加而增加,吸附符合Freundlich等温式,无最大饱和吸附量;吸附氟离子的复合膜可以脱附再生,且再生后仍具有较高的吸附容量。     

改性水滑石类材料的制备及其吸附性能研究进展

水滑石和类水滑石及其插层材料统称为水滑石类材料(layered double hydroxides,LDHs)。在分析层状结构的基础上,综述改性LDHs的制备方法及其在废水处理中的吸附去除性能应用进展。制备改性LDHs主要有共沉淀法、水热及溶剂热法、离子交换法和焙烧复原法。共沉淀法工艺简单,条件易控,合成周期短;水热及溶剂热法产品粒子纯度高,晶形可控,生产成本低;离子交换法反应时间短,通过在层间容纳不同的阴离子调整LDHs性能并保持层状结构;焙烧复原法利用"记忆效应"实现LDHs重复利用;磁性LDHs具有超顺磁性,可快速回收固体吸附剂。改性LDHs的阴离子交换容量高,热稳定性良好,比表面积大,可以有效吸附去除废水中的重金属离子、有机污染物和无机阴离子。改性LDHs可广泛应用于催化、吸附、医药、阻燃、离子交换等领域。     

三维石墨烯的水热法制备及其吸附性能研究

系统研究了一种在水热条件下制备三维石墨烯的新方法,建立了最佳的稳定制备工艺。该方法不需要添加化学交联剂,简单、可控性高。经X射线衍射、扫描电镜、视频接触角测量仪,拉曼光谱检测分析表明,制备的三维石墨烯样品具有密度低、孔隙率、机械强度及吸附率高的特点,与其它方法相比,此制备工艺具有较好的稳定性和重复性。制备的三维石墨烯有望应用在超级电容器、储氢材料、催化剂和环境保护等方面。     

Removal mechanism of phosphate from aqueous solution by fly ash

This work studied the effectiveness of fly ash in removing phosphate from aqueous solution and its related removal mechanism. The adsorption and precipitation of phosphate by fly ash were investigated separately in order to evaluate their role in the removal of phosphate. Results showed that the removal of phosphate by fly ash was rapid. The removal percentage of phosphate in the first 5min reached 68-96% of the maximum removal of phosphate by fly ash. The removal processes of phosphate by fly ash included a fast and large removal representing precipitation, then a slower and longer removal due to adsorption. The adsorption of phosphate on fly ash could be described well by Freundlich isotherm equation. The pH and Ca2+ concentration of fly ash suspension were decreased with the addition of phosphate, which suggests that calcium phosphate precipitation is a major mechanism of the phosphate removal. Comparison of the relative contribution of the adsorption and precipitation to the total removal of phosphate by fly ash showed that the adsorption accounted for 30-34% of the total removal of phosphate, depending on the content of CaO in fly ash. XRD patterns of the fly ash before and after phosphate adsorption revealed that phosphate salt (CaHPO4 x 2H2O) was formed in the adsorption process. Therefore, the removal of phosphate by fly ash can be attributed to the formation of phosphate precipitation as a brushite and the adsorption on hydroxylated oxides. The results suggested that the use of fly ash could be a promising solution to the removal of phosphate in the wastewater treatment and pollution control.     

转炉污泥吸附性能研究

Converter sludge, a byproduct produced on large amounts in the steel making process, is an important resource that can be utilized effectively. This paper describes an experiment in which converter sludge was tested as an adsorbent for the removal of phosphorus from waste water. It was found that the phosphorus removal depended on the amount of converter sludge added, the pH value and the contact time. Under laboratory conditions when the added sludge was 2. 0mg/100ml, the contact time 4h and the pH value of equalized 4, over 88% of phosphorus was removed; the experimental data on converter sludge adsorption of phosphorus in the water fitted the Freundlich isotherm model. Converter sludge was found to be very effective in adsorbing the phosphorus.     

LiFePO4/C正极材料的液相合成及电化学性能研究

采用磷酸三丁酯(TBP)为多功能反应物并添加表面活性剂PEG-4000合成了LiFePO4/C正极材料,利用XRD、SEM、XPS和滴定分析对产品进行了结构、表面形貌和化学组成表征.结果表明在650℃烧结15h所得产物结晶良好,为均匀分布在100nm左右的类球形颗粒.循环伏安曲线显示,该样品具有对称且尖锐的氧化还原电位峰,表明材料具有良好的电化学可逆性.在0.1mA/cm2电流密度下,其首次充放电比容量分别为162和158mAh/g,经100次循环后放电容量损失率仅为3.3%,当充放电密度增加到4mA/cm2时,材料的放电比容量仍然接近100mAh/g,倍率性能优良.     

Removal of phosphate from polluted water by lanthanum doped vesuvianite

The adsorption capacities of vesuvianite and lanthanum doped vesuvianite were studied. The effects of different mass ratios of La/vesuvianite at different contact times, pHs, and temperatures on adsorption capacity were also studied. It was found that lanthanum doped vesuvianite exhibited higher adsorption capacity than undoped one due to the reaction of bounded lanthanum with phosphate. The adsorption capacity of lanthanum doped vesuvianite for phosphate removal increased with the increase of La/vesuvianite mass ratio. The Freundlich and Langmuir models were used to simulate the sorption equilibrium, and the results indicate that the Langmuir model had a better correlation with the experimental data than the Freundlich model did. When the initial phosphate concentration was 1 mg P/L, the adsorptive capacity rate would be 1.32 mg P/g lanthanum doped vesuvianite (La/vesuvianite mass ratio ≥0.14) at pH between 6 and 9 after 40 h. The concentrations of residual lanthanum ions in solution at different conditions were measured. Lanthanum doped vesuvianite was also used for the removal of phosphate in a polluted river water and it could be easily recycled once without losing its activity to a greater extent.     

Removal of aniline from aqueous solution by PVC-CDAE ligand-exchanger

The adsorption of aniline from aqueous solutions onto cobalt(II)-poly(vinyl chloride)-carboxylated diaminoethane (PVC-CDAE) resin has been studied using a mini-column apparatus at 25 ± 0.1 °C. First of all, experimental data obtained from the breakthrough curves were tested by using the Scatchard plot analysis, to have a preliminary prediction about the types of interaction of the resin with aniline. Our aim was to determine the model which best describes the experimental data. The aspect of the Scatchard plot indicated that the aniline adsorption did not follow the Langmuir model and the presence of two types of binding sites for aniline on the resin. However, the dynamics of aniline uptake were represented by the Freundlich model reasonably well. The kinetics of aniline adsorption from aqueous solution on the cobalt(II)-PVC-CDAE have also been tested using continuous column runs and rate-controlling step of the process was determined. In this study, homogeneous diffusion model was adapted to a column system to describe the change in the aniline concentration at the column exit beginning from breakthrough point as a function of time. Kinetic studies revealed that the rate-controlling step of the aniline adsorption was predominately film diffusion controlled rather particle diffusion.     

Removal of phosphate from aqueous solutions and sewage using natural and surface modified coir pith

Iron impregnated coir pith (CP-Fe-I) can be effectively used for the removal of phosphate from aqueous streams and sewage. Iron impregnation on natural coir pith was carried out by drop by drop addition method. The effect of various factors such as pH, initial concentration of phosphate, contact time and adsorbent dose on phosphate adsorption was studied by batch technique. The pH at 3.0 favored the maximum adsorption of phosphate from aqueous solutions. The effect of pH on phosphate adsorption was explained by pH(zpc), phosphate speciation in solution and affinity of anions towards the adsorbent sites. A comparative study of the adsorption of phosphate using CP-Fe-I and CP (coir pith) was made and results show that the former one is five to six times more effective than the latter. Kinetic studies revealed that the adsorption process followed a pseudo-second order kinetic model. Adsorption followed Langmuir isotherm model. Column studies were conducted to examine the utility of the investigated adsorbent for the removal of phosphate from continuously flowing aqueous solutions.     

Kinetics of adsorption of dyes from aqueous solution using activated carbon prepared from waste apricot

Adsorbent (WA11Zn5) has been prepared from waste apricot by chemical activation with ZnCl(2). Pore properties of the activated carbon such as BET surface area, pore volume, pore size distribution, and pore diameter were characterized by N(2) adsorption and DFT plus software. Adsorption of three dyes, namely, Methylene Blue (MB), Malachite Green (MG), Crystal Violet (CV), onto activated carbon in aqueous solution was studied in a batch system with respect to contact time, temperature. The kinetics of adsorption of MB, MG and CV have been discussed using six kinetic models, i.e., the pseudo-first-order model, the pseudo-second-order model, the Elovich equation, the intraparticle diffusion model, the Bangham equation, the modified Freundlich equation. Kinetic parameters and correlation coefficients were determined. It was shown that the second-order kinetic equation could describe the adsorption kinetics for three dyes. The dyes uptake process was found to be controlled by external mass transfer at earlier stages (before 5 min) and by intraparticle diffusion at later stages (after 5 min). Thermodynamic parameters, such as DeltaG, DeltaH and DeltaS, have been calculated by using the thermodynamic equilibrium coefficient obtained at different temperatures and concentrations. The thermodynamics of dyes-WA11Zn5 system indicates endothermic process.     

Removal of metals from aqueous solution and sea water by functionalized graphite nanoplatelets based electrodes

In the present wok, we have demonstrated the simultaneous removal of sodium and arsenic (pentavalent and trivalent) from aqueous solution using functionalized graphite nanoplatelets (f-GNP) based electrodes. In addition, these electrodes based water filter was used for multiple metals removal from sea water. Graphite nanoplatelets (GNP) were prepared by acid intercalation and thermal exfoliation. Functionalization of GNP was done by further acid treatment. Material was characterized by different characterization techniques. Performance of supercapacitor based water filter was analyzed for the removal of high concentration of arsenic (trivalent and pentavalent) and sodium as well as for desalination of sea water, using cyclic voltametry (CV) and inductive coupled plasma-optical emission spectroscopy (ICP-OES) techniques. Adsorption isotherms and kinetic characteristics were studied for the simultaneous removal of sodium and arsenic (both trivalent and pentavalent). Maximum adsorption capacities of 27, 29 and 32 mg/g for arsenate, arsenite and sodium were achieved in addition to good removal efficiency for sodium, magnesium, calcium and potassium from sea water.     

Removal of phosphate species from solution by adsorption onto calcite used as natural adsorbent

Phosphates are very important basic materials in agricultural and other industrial applications. Phosphorus is often present in low concentrations in wastewater, almost solely in the form of organic and inorganic phosphates (ortho- and poly-phosphates). The removal of phosphates from surface waters is generally necessary to avoid problems, such as eutrophication, particularly near urban areas. The usual methods of treatment are either biological or physicochemical by sedimentation. This paper studies the removal of phosphate species by adsorption onto calcite used as natural adsorbent. The phosphate solutions were prepared artificially by adding certain quantities of K2HPO4 in water. The effect of equilibrium pH, phosphate/mineral ratio and contact time was studied. The results showed that pH plays an important role in the removal of phosphate species from solution, with removal being more efficient in the basic pH region. The experimental results also show that adsorption is also efficient for high ratios phosphate/adsorbent. Finally, the adsorption process is time dependent. Based on the experimental results a possible mechanism of phosphate removal onto calcite surface is proposed. As a general conclusion, phosphate species seem to be efficiently removed from solutions using calcite as natural adsorbent. In addition, the adsorption product can be used as fertilizer for acid soils.