氢氧化镧改性介孔稻壳生物炭除磷性能

通过共沉淀法将氢氧化镧固定在高介孔率的稻壳生物炭上,重点研究了生物炭孔结构、溶液pH和共存物质对氢氧化镧改性介孔稻壳生物炭吸附磷酸盐的影响.结果表明,镧负载量与生物炭介孔率呈正相关,生物炭介孔率越高,对磷酸盐的吸附速率越快,镧浸出量越低.吸附过程符合伪二级动力学模型,且受颗粒内扩散控制.Langmuir模型能够较好地描述氢氧化镧改性介孔稻壳生物炭对磷酸盐的吸附过程,理论最大吸附量分别为41.22、43.26和45.62 mg·g^-1,镧利用率较高,P/La量比均大于1.5.此外,氢氧化镧改性介孔稻壳生物炭能在pH 3~9的范围内有效吸附磷酸盐.共存物质影响实验表明,氢氧化镧改性介孔稻壳生物炭对磷酸盐表现出良好的选择吸附性,共存Ca²⁺会强化其对磷酸盐的吸附,而共存Mg²⁺则会抑制吸附过程.     

镧对UV-B胁迫下大豆幼苗类黄酮含量与抗氧化能力影响

为进一步认识La(Ⅲ)提高类黄酮含量及减轻UV-B辐射伤害植物机制,以大豆幼苗为材料,采用水培实验的方法研究了La(Ⅲ)对UV-B辐射胁迫下大豆幼苗类黄酮抗氧化能力的动态影响.结果表明, UV-B辐射(T1:0.15W·m-2和T2:0.45W·m-2)胁迫下,大豆幼苗类黄酮含量在胁迫期和恢复期均先升后降,质膜透性、MDA含量先升(1～5d)后降(6～11d),类黄酮对O·-2和·OH的清除率与其含量变化趋势近同.各处理组类黄酮含量La(Ⅲ) UV-B>UV-B>La(Ⅲ)>CK, La(Ⅲ) T1>La(Ⅲ) T2;质膜透性、MDA含量UV-B>La(Ⅲ) UV-B>CK>La(Ⅲ), La(Ⅲ) T2>La(Ⅲ) T1;类黄酮对O-2和·OH清除率La(Ⅲ) UV-B>UV-B>La(Ⅲ)>CK, La(Ⅲ) T1, La(Ⅲ) T2,表明La(Ⅲ)对类黄酮的调控作用,提高了清除活性氧自由基的运行效率,降低了MDA浓度,维持了质膜正常透性,且对低剂量(T1)的防护效果优于高剂量(T2),进而在防御系统层面实现了La(Ⅲ)对UV-B辐射伤害大豆幼苗的防护效应.     

磁性吸附材料CuFe2O4吸附砷的性能

根据Cu(Ⅱ)和Fe(Ⅲ)都对砷有较强的亲和性,制备了同时含有Cu(Ⅱ)和Fe(Ⅲ)的、可用磁分离方法进行分离回收的磁性吸附材料CuFe₂O₄,并对其进行了表征及吸附砷的性能研究.结果表明,该吸附剂对砷的吸附能力与溶液pH有关,在弱酸性及中性条件下,吸附砷的能力最强,而对As(V)的吸附能力比对As(Ⅲ)更强些,在平衡浓度为10μg/L时,其吸附容量可达10mg/g左右,可以很容易地将水中浓度为1～20mg/L的As(V)降到10μg/L以下.实验考察了几种无机阴离子对吸附砷的影响,表明较高浓度(砷浓度的20倍)的硫酸盐对As(Ⅲ)和As(V)的吸附均有一定影响,盐酸盐及磷酸盐则影响不明显;负载的As(V)可较容易地用0.1mol/L NaOH洗脱下来,使吸附剂再生,而As(Ⅲ)则难以洗脱,这与2种价态砷的吸附机理不同有关.     

Arsenic and cadmium removal from water by a calcium-modified and starch-stabilized ferromanganese binary oxide

A new calcium-modified and starch-stabilized ferromanganese binary oxide (Ca-SFMBO) sorbent was fabricated with different Ca concentrations for the adsorption of arsenic (As) and cadmium (Cd) in water. The maximum As(III) and Cd(II) adsorption capacities of 1% Ca-SFMBO were 156.25 mg/g and 107.53 mg/g respectively in single-adsorption systems. The adsorption of As and Cd by the Ca-SFMBO sorbent was pH-dependent at values from 1 to 7, with an optimal adsorption pH of 6. In the dual-adsorbate system, the presence of Cd(II) at low concentrations enhanced As(III) adsorption by 33.3%, while the adsorption of As(III) was inhibited with the increase of Cd(II) concentration. Moreover, the addition of As(III) increased the adsorption capacity for Cd(II) up to two-fold. Through analysis by X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FTIR), it was inferred that the mechanism for the co-adsorption of Cd(II) and As(III) included both competitive and synergistic effects, which resulted from the formation of ternary complexes. The results indicate that the Ca-SFMBO material developed here could be used for the simultaneous removal of As(III) and Cd(II) from contaminated water.     

牛血清白蛋白对Ni2+与δ-MnO2间吸附平衡的影响

研究了溶液中牛血清白蛋白(BSA)的存在对Ni2 与δ-MnO2衡性质的影响.结果表明, BSA存在时Ni2 在δ-MnO2表面的吸附率'pH曲线仍为典型的"S"形, BSA使Ni2 的吸附突跃向高pH方向移动,影响程度与BSA的加入方式及浓度有关,其大小次序为Ⅳ(先加BSA后加Ni2 ),Ⅲ(N2 和BSA同时加)≈Ⅱ(先加Ni26 后加BSA).BSA存在时Ni2 的等温吸附线很好地遵循Langmuir等温吸附方程, Ni2 的饱和吸附量与BSA的加入方式有关,其大小次序为I(不加BSA)>Ⅱ.m,Ⅳ.升高温度促进Ni2 的吸附.在pH:4.0和pH:7.0条件下, Ni2 在δ-MnO2上的吸附均是不可逆的, BSA对Ni2 的吸附可逆性没有影响.     

氢氧化镧掺杂氧化铝去除水体磷酸盐性能研究

为有效去除水体中的磷酸盐,采用沉淀沉积方法合成了氢氧化镧〔La(OH)₃〕掺杂氧化铝(Al₂O₃)的吸附材料La(OH)₃(X)/Al₂O₃〔X表示吸附剂中的La(OH)₃质量含量〕,并对其吸附磷酸盐的性能进行研究. 结果表明:①Al₂O₃和La(OH)₃是吸附剂中磷酸盐的主要结合位点. ②磷酸盐初始浓度为50 mg/L时,La(OH)₃(19)/Al₂O₃吸附剂在初始阶段吸附较快,且在200 min左右达到吸附平衡. La(OH)₃(X)/Al₂O₃吸附剂对磷酸盐的吸附量随着La(OH)₃负载量的提高而升高,其吸附等温线符合Langmuir模型拟合. La(OH)₃(7)/Al₂O₃、La(OH)₃(13)/Al₂O₃、La(OH)₃(19)/Al₂O₃和La(OH)₃(27)/Al₂O₃对磷酸盐的最大吸附量可分别达到25.32、27.40、43.10和53.76 mg/g (以P计). 这表明La(OH)₃掺杂Al₂O₃后为磷酸盐提供更多的活性位点,有效提高了磷酸盐的吸附容量. ③La(OH)₃(19)/Al₂O₃对磷酸盐的吸附量随pH的升高而降低,共存阴离子影响试验表明,La(OH)₃(19)/Al₂O₃对磷酸盐具有较高的吸附选择性. ④经过5次吸附-脱附循环后,La(OH)₃(19)/Al₂O₃表现出稳定的吸附和再生性能,对实际水体磷酸盐的去除试验结果表明其可用于实际水体中磷酸盐的去除. 研究显示,La(OH)₃(19)/Al₂O₃的磷酸盐吸附速率快、吸附容量高、吸附选择性高,具有潜在的应用价值.      

Adsorptive removal of phosphate by the bimetallic hydroxide nanocomposites embedded in pomegranate peel

This study aimed to fabricate new and effective material for the efficiency of phosphate adsorption. Two types of adsorbent materials, the zirconium hydroxides embedded in pomegranate peel (Zr/Peel) and zirconium-lanthanum hydroxides embedded in pomegranate peel (Zr–La/Peel) were developed. Scanning electronic microscopy (SEM), x-ray photoelectron spectroscopy (XPS) and x-ray diffraction (XRD) were evaluated to give insight into the physicochemical properties of these adsorbents. Zr–La/Peel exceeded the adsorption efficiency of Zr/Peel adsorbents in batch adsorption experiments at the same pH level. The peel as a host can strive to have a strong “shielding effect” to increase the steadiness of the entrenched Zr and La elements. La and Zr are hydroxide metals that emit many hydrogen ions during the hydrolysis reaction, which contribute to protonation and electrostatic attraction. The highest adsorption capacity of La–Zr/Peel for phosphate was calculated to be 40.21 mg/g, and pseudo second-order equation is very well fitted for kinetic adsorption. Phosphate adsorption efficiency was reduced by an increase of pH. With the background of coexisting Cl^?, little effect on adsorption efficiency was observed, while adsorption capacities were reduced by almost 20–30% with the coexistence of ${{\text{SO}}_4}^{2?}$, ${{\text{NO}}_3}^{?}$ and humic acid (HA).     

La3+、Yb3+在土壤和矿物中的吸附特征及其环境意义

实验研究了轻稀土镧离子Ｌａ~３＋和重稀土镱离子Ｙｂ~３＋在赣南稀上矿区的土壤及风化次生矿物中的吸附特性，结果表明，土壤和矿物对稀土元素的吸附过程符合Ｌａｎｇｍｕｉｒ和Ｆｒｅｎｄｌｉｃｈ等温吸附方程，ｐＨ值是影响吸附作用的主要因素。随着ｐＨ值的变化，Ｌａ~３＋和Ｙｂ~３＋在土壤和次生矿物上的吸附能力也发生变化。Ｌａ~３＋与Ｙｂ~３＋在土壤和次生矿物中的吸附等势点ｐＨ值分别为６．２６和５．２８．在等势点ｐＨ值以下，Ｌａ~３＋的吸附势大于Ｙｂ~３＋；在等势点ｐＨ值以上，Ｙｂ~３＋的吸附势相对较高。土壤和次生矿物对轻、重稀土元素的吸附特征以及对稀士元素的分布、分异、成矿和生态效应具有重要意义。     

新型Fe3O4@SA/La复合凝胶微球的制备及吸附性能

将海藻酸钠（SA）、Fe₃O₄和La（Ⅲ）离子通过溶液反应法制得一种新型磁性海藻酸镧复合凝胶微球（Fe₃O₄@SA/La）,采用扫描电子显微镜（SEM）、X射线衍射（XRD）及红外光谱（FT-IR）等进行表征.以直接红棕RN（DRB RN）和直接深棕2M（DDB 2M）2种直接染料为吸附对象,考察了染料溶液pH值、吸附时间和温度对吸附剂性能的影响.结果表明：在吸附剂投加量为0.1g、染料溶液自然pH值条件下,Fe₃O₄@SA/La复合凝胶微球室温下对DDB 2M和DRB RN均有良好的吸附性,120min即可达吸附平衡,吸附量分别可达678和688mg/g.吸附过程符合拟二级吸附动力学方程,等温吸附符合Freundlich模型.吸附剂对2种染料的吸附热力学参数（ΔG<0、ΔH<0、ΔS>0）表明吸附反应均为混乱度增加的自发放热反应.     

表生稀土矿区土壤中稀土元素的吸附特征

研究了赣南典型表生稀土矿区土壤中稀土元素的吸附特征及其主要影响因素。结果表明，稀土元素（Ｌａ，Ｙｂ）的吸附过程符合Ｌａｎｇｍｕｉｒ和Ｆｒｅｎｄｌｉｅｃｈ等温方程，稀土绵吸附以可交换吸附为主，ＰＨ值是影响土壤中稀土元素吸附的极重要因素，随着ＰＨ值的增加，稀土吸附量增加，土壤去除有机质后，对稀土的吸附量下降约７．６％；去游离氧化铁后，稀土元素的吸附量增长７．４％，不同阴离子条件下，土壤对稀土元素的吸附     

3种耐锑土壤细菌的筛选及对锑的吸附研究

从湖南省冷水江锡矿山尾渣土壤中筛选分离出3株具有较高锑耐性的细菌,通过宏观吸附结合X射线光电子能谱（XPS）,阐明3株细菌对Sb（Ⅲ）和Sb（Ⅴ）的吸附机制.根据生理生化指标和16S rDNA序列同源性对比,鉴定出1株革兰氏阴性菌和2株革兰氏阳性菌,分别为人苍白杆菌（Ochrobactrum anthropi）、芽孢杆菌（Bacillus sp.）及蜡状芽孢杆菌（Bacillus cereus）.3株细菌都呈杆状,且都能在高锑含量营养液中良好生长.3株细菌对锑的等温吸附符合Langmuir模型,对锑的最大吸附量约为11.0~14.3 mg·g^-1,其中,蜡状芽孢杆菌对锑的吸附能力高于其它两株细菌,3株细菌对Sb（Ⅲ）的吸附量略高于Sb（Ⅴ）.XPS结果表明,细菌表面的羧基和氨基在锑吸附过程中发挥主导作用.本研究结果对于理解土壤微生物吸附固定锑机制及其在土壤修复中的应用有重要意义.     

天然菱铁矿改性及强化除砷研究

我国高砷地下水分布广泛,经济、高效地饮用水除砷技术受到广泛关注.静态批实验采用资源丰富、价格便宜的天然菱铁矿为主要原材料,考虑灼烧温度、时间及添加黏合剂等因素确定最优改性条件使除砷效果达到最佳.结果表明,在加铝量为10 mg.g-1、350℃下恒温灼烧90 min后造粒达到强度要求并除砷效果较优.25℃、固液比为0.5 g∶50 mL、As(Ⅲ)和As(Ⅴ)初始浓度为5 mg.L-1时,吸附后溶液中残留As浓度均<10μg.L-1.静态吸附批实验结果表明,25℃时,接触反应时间为12 h可达到吸附平衡,吸附过程较好地符合Lagergren假二级吸附速率方程;最优改性天然菱铁矿对砷的吸附规律可用Langmuir和Freundlich等温吸附模型很好地描述,As(Ⅲ)、As(Ⅴ)饱和吸附容量分别可以达到1 039、1 026μg.g-1.结合XRD、SEM等研究方法和比表面及孔结构分析初步探讨天然菱铁矿改性以及除砷的主要机制.分析表明,改性后天然菱铁矿比表面积大幅度增大,孔径减小,且在表面活化生成一层圆球状的含Fe(Ⅱ)和Fe(Ⅲ)的化合物.改性天然菱铁矿是一种值得进一步研究并实际应用的除砷材料.     

Adsorption behavior of phosphate on Lanthanum(Ⅲ) doped mesoporous silicates material

A series of lanthanum doped meosoporous MCM-41 (La_xM41, x is Si/La molar ratio) was prepared by sol-gel method. The surface structure of the materials was investigated with X-ray diffraction and N_2 adsorption/desorption technique. The content of La in the materials was determined by ICP. It was found that the La content of La_(25)M41, La_(50)M41 and La_(100)M41 was 7.53%, 3.89% and 2.32%, respectively. The phosphate adsorption capacities increased with increasing amount of La incorporation. With 0.40 g La_(25)M41 99.7% phosphate could be removed. The effects of Si/La molar ratio, La_xM41 dose, pH, initial concentration of phosphate solution, co-ions on phosphate adsorption were also evaluated. The phosphate adsorption kinetics of La_xM41 could be well-described by the pseudo second-order model, and Langmuir isotherm fit equilibrium data much better than the Freundlich isotherm.     

Adsorption behavior of phosphate on Lanthanum（III） doped mesoporous silicates material

A series of lanthanum doped meosoporous MCM-41 (LaxM41, x is Si/La molar ratio) was prepared by sol-gel method. The surface structure of the materials was investigated with X-ray diffraction and N2 adsorption/desorption technique. The content of La in the materials was determined by ICP. It was found that the La content of La25M41, La50M41 and La100M41 was 7.53%, 3.89% and 2.32%, respectively. The phosphate adsorption capacities increased with increasing amount of La incorporation. With 0.40 g La25M41 99.7% phosphate could be removed. The effects of Si/La molar ratio, LaxM41 dose, pH, initial concentration of phosphate solution, co-ions on phosphate adsorption were also evaluated. The phosphate adsorption kinetics of LaxM41 could be well-described by the pseudo second-order model, and Langmuir isotherm fit equilibrium data much better than the Freundlich isotherm.     

改性纳米零价铁对稻田土壤As污染的修复效能

为实现对稻田土壤As污染的高效修复,通过制备C-NZVI(壳聚糖基稳定化纳米零价铁),分析其对还原态亚砷酸〔As(Ⅲ)〕的吸附动力学和等温吸附特征,阐明典型竞争性阴离子/分子对C-NZVI吸附As(Ⅲ)效率的影响;在此基础上,重点研究淹水和拮抗性肥料对稻土As的强化溶出效应,揭示C-NZVI对稻土液相As的异位吸附去除与原位补充钝化作用.结果表明:准一级动力学和Langmuir等温吸附模型能很好地描述C-NZVI对As(Ⅲ)的吸附过程特征,该材料对As(Ⅲ)的最大吸附量为145.09 mg/g;当竞争性K₂HPO₄、H₃BO₃、Na₂SiO₃和CH₃COOH的摩尔浓度为0.05~0.50 mmol/L时,C-NZVI对As(Ⅲ)的去除率依然高达99%.在对稻田土壤进行淹水和依次施用NH₄H₂PO₄、(NH₄)₂C₂O₄、Na₂SiO₃三种拮抗性肥料条件下,稻土中累积溶出w(水溶态As)(18.1 mg/kg)达到土壤w(As)的30.0%;对强化溶出反应后的淹水稻土进行排水并利用C-NZVI对各步分离获得的含As液相进行异位吸附,As去除率为91.3%~99.8%,该过程使稻土中w(As)减少43.4%~52.6%;进一步利用1%和5%的C-NZVI对强化溶出后的稻土进行补充钝化,可使稻土中w(非专性吸附态As)降低94.7%~100%.研究显示,淹水强化条件下,利用C-NZVI对稻田土壤As污染进行异位去除与原位钝化的联合修复可为有效减控稻田土壤As生物有效性提供有益途径.      

High phosphate removal using La(OH)3 loaded chitosan based composites and mechanistic study

Our present study was to prepare a biomass-supported adsorbents with high adsorptive capacity and high selectivity to prevent the accelerated eutrophication in water body. To this end, different metal hydroxide (La, Zr and Fe) first was successfully loaded on chitosan microspheres. Then the quaternary ammonium group with different content was introduced into the adsorbent by polymerization. By comparison of adsorption properties, chitosan-La(OH)₃-quaternary ammonium-20% (CS-La-N-20%) has strong adsorption to phosphate (160 mg/g) by immobilizing nano-sized La(OH)₃ within a quaternary-aminated chitosan and it maintain high adsorption in the presence of salt ions. The pH results indicated that the CS-La-N-20% would effectively sequestrate phosphate over a wide pH range between 3 and 7 without significant La³⁺ leaching. What's more, adsorption capacity on the introduce of positively charged quanternary-aminated groups was significantly higher than that of the unmodified adsorbents at alkaline conditions. The column adsorption capacity reached 1300 bed volumes (BV) when phosphate concentration decreased until 0.5 mg/L at 6 BV/hr. The column adsorption/desorption reveals that no significant capacity loss is observed, indicating excellent stability and repeated use property. Characterizations revealed that phosphate adsorption on CS-La-N-20% through ligand exchange (impregnated nano-La(OH)₃) and electrostatic attraction (positively charged quanternary-aminated groups). All the results suggested that CS-La-N-20% can serve as a promising adsorbent for preferable phosphate removal in realistic application.     

Adsorption of Cr(Ⅲ) from acidic solutions by crop straw derived biochars

Cr（Ⅲ） adsorption by biochars generated from peanut, soybean, canola and rice straws is investigated with batch methods. Adsorption of Cr（Ⅲ） increased as pH rose from 2.5 to 5.0. Adsorption of Cr（Ⅲ） led to peak position shifts in the FFIR-PAS spectra of the biochars and made zeta potential values less negative, suggesting the formation of surface complexes between Cr^3＋ and functional groups on the biochars. The adsorption capacity of Cr（Ⅲ） followed the order： peanut straw char 〉 soybean straw char 〉 canola straw char 〉 rice straw char, which was consistent with the content of acidic functional groups on the biochars. The increase in Cr^3＋ hydrolysis as the pH rose was one of the main reasons for the increased adsorption of Cr（Ⅲ） by the biochars at higher pH values. Cr（llI） can be adsorbed by the biochars through electrostatic attraction between negative surfaces and Cr^3＋, but the relative contribution of electrostatic adsorption was less than 5%. Therefore, Cr（Ⅲ） was mainly adsorbed by the biochars through specific adsorption. The Langumir and Freundlich equations fitted the adsorption isotherms well and can therefore be used to describe the adsorption behavior of Cr（Ⅲ） by the crop straw biochars. The crop straw biochars have great adsorption capacities for Cr（Ⅲ） under acidic conditions and can be used as adsorbents to remove Cr（Ⅲ） from acidic wastewaters.     

Preparation and evaluation of Zr-β-FeOOH for efficient arsenic removal

A Zr-β-FeOOH adsorbent for both As(V) and As(III) removal was prepared by a chemical co-precipitation method.Compared with β-FeOOH,the addition of Zr enhanced the adsorption capacities for As(V) and As(III),especially As(III).The maximum adsorption capacities for As(III) and As(V) were 120 and 60mg/g respectively at pH 7.0,much higher than for many reported adsorbents.The adsorption data accorded with Freundlich isotherms.At neutral pH,for As(V),adsorption equilibrium was approached after 3 hr,while for As(III),adsorption equilibrium was approached after 5 hr.Kinetic data fitted well to the pseudo second-order reaction model.As(V) elimination was favored at acidic pH,whereas the adsorption of As(III) by Zr-β-FeOOH was found to be effective over a wide pH range of 4-10.Competitive anions hindered the adsorption according to the sequence:phosphate > silicate > bicarbonate > sulfate > nitrate,while Ca2+ and Mg2+ increased the removal of As(III) and As(V) slightly.The high adsorption capability and good performance in other aspects make Zr-β-FeOOH a potentially attractive adsorbent for the removal of both As(III) and As(V) from water.     

Metal affinities in single and multiple ion adsorption reaction at sulfide mineral surfaces

Sulfide minerals are found in porous media in both aerobic and anaerobic environments, they should have a high affinities for certain metals. The relative binding affinities and reaction processes for 10 metal/metalloid ions reacting with four sulfide mineral surfaces has been defined.The order of reactivity is chalcocite > pyrite > galena >> sphalerite. For any particular metal and mineral, the greater reactivity occurs in the single-ion metal system except Ag(I) on pyrite and Cu(II) on galena.Both precipitation and adsorption reaction can decrease metal ion mobility on porous media, the order of metal mobility in the presence of the four sulfide minerals is predicted to be: Zn(II), Cd(II) and Ni(II) - mobile; Cu(II), Pb(II), Fe(III), As(III) and Cr(III) - variable mobility and Ag(I) - immobile.MINTEQA1 predictions on metal phase distribution / partitioning compared quite well with those observed experimentally. Solubility product considerations, intrinsic acidity constant of the mineral, EH, pH and th