垃圾焚烧飞灰去除硫化氢气体

生活垃圾焚烧飞灰由于含有铅镉等重金属,是一种危险废物,若处理不当,会造成重金属迁移和污染地下水等环境生态问题.近年来,垃圾焚烧飞灰的污染控制及资源化利用得到国内人广泛的关注.以垃圾焚烧飞灰为吸附材料,对比研究了2种不同性质的垃圾焚烧飞灰、热电厂粉煤灰以及砂土在相同条件下对硫化氢(H2S)的吸附性能.结果表明,垃圾焚烧飞灰的H2S吸附能力优于其他吸附材料.通过分析吸附前后垃圾焚烧飞灰的浸出液毒性,发现吸附前Cd、Pb 2种金属离子浓度超标,H2S吸附后的飞灰浸出液中金属离子浓度均有一定程度的降低.     

巯基改性膨润土对小白菜吸收累积镍的影响

盆栽条件下,采用巯基改性膨润土(以下简称巯基土)为重金属钝化材料修复镍污染土壤,考察在不同镍污染程度和土壤pH下,其对盆栽小白菜吸收累积镍的影响。结果表明,巯基土可明显降低高污染土盆栽小白菜对镍的吸收累积。将巯基土按1∶1的质量比与成本较低的钠化改性膨润土混合制成混合材料,混合材料对低污染土有良好修复效果,当混合材料添加量为2.0%(质量分数)时,低污染土盆栽小白菜中的镍含量比空白对照(CK)组降低了41.8%。土壤pH为5.50时,混合材料对镍污染土壤的修复效果最好。土壤总镍含量与有效态镍含量占比呈负相关关系,盆栽小白菜中镍含量与盆栽土壤有效态镍含量占比呈极显著正相关关系。在利用重金属修复材料进行污染治理时,除关注重金属总量外,更应根据土壤中重金属的赋存形态,尤其是有效态含量来决定修复材料的施加量。     

改性膨润土对水体中多环芳烃的吸附

改性膨润土被广泛地应用于吸附水体中重金属离子和有机污染物,但关于改性膨润土吸附水体中多环芳烃混合物的动力学研究鲜见报道。利用十二烷基三甲溴化铵和十二烷基磺酸钠对膨润土进行改性,并将之应用于吸附水体中萘、蒽、菲和芘4种多环芳烃,考察了吸附剂投加量、时间和温度等条件对吸附效果的影响。实验结果表明,在25℃、吸附时间40 min、起始浓度为1.25 mg/m L、改性膨润土的投加量为4 g/L的条件下,该吸附剂对萘、蒽、菲和芘的吸附率分别为99.1%、99.6%、98.7%和98.9%。改性膨润土对水体中4种多环芳烃的吸附机理服从准二级动力学方程,该吸附剂吸附等温线服从Langmuir方程。     

膨润土的2种不同柱撑改性方式及其吸附重金属锌离子的比较

考察了钙基膨润土钠化过程中改性剂的用量,矿浆浓度,改性时间等对改性效果的影响,并测试了不同超声反应时间、陈化时间等条件下制备的钠化膨润土的性能,如:膨胀容,膨润值和阳离子交换容量CEC,然后分别以Al13-Cl和Al13-SO4方式嵌入矿物层间域中制备柱撑膨润土,考察和比较了不同陈化时间下2种柱撑膨润土煅烧前后的微观结构,及其对污水中锌离子的吸附去除效果,结果表明,Al13-Cl改性方法制备的柱撑膨润土对锌离子的吸附性能明显优于Al13-SO4柱撑效果。     

羟基金属柱撑膨润土吸附氟的性能研究

将膨润土进行改性制得4种羟基金属柱撑膨润土,用XRD考察了层间结构,并将它们应用于含氟废水的吸附处理中,研究了各种吸附剂的吸附速率、介质的pH、吸附剂用量、饱和吸附曲线和吸附剂的重复使用性.结果表明,改性得到的羟基金属柱撑膨润土的层间距都明显变大,在实验条件下对氟离子的吸附性能为羟基铁铝复合柱撑膨润土>羟基铁柱撑膨润土>羟基铝柱撑膨润土.该类吸附剂对氟离子还具有较好的重复使用性.     

改性油页岩灰渣对水中镉离子的吸附性能

采用酸碱化改性方法对油页岩灰渣进行改性,确定最佳酸碱化方案,并研究了环境因素对改性油页岩灰渣吸附镉离子的影响。实验研究结果表明,油页岩灰渣经50%的HNO3和20%的NaOH处理时,对镉离子的吸附能力最强。在吸附温度为30℃,初始溶液pH为6～7条件下,0.6 g的改性油页岩灰渣对50 mg/L Cd2+溶液50 mL,吸附150 min时,其吸附率达到86%以上。在实验条件下,改性油页岩灰渣对Cd2+的吸附符合Langmuir和Freundlich等温吸附方程,相关系数分别为0.9626和0.9944,其对Cd2+的理论饱和吸附量达到7.91 mg/g。改性油页岩灰渣对Cd2+的吸附主要归因于离子交换和表面吸附作用。     

有机膨润土吸附苯胺的性能及其在水处理中的应用

分别用氯化十六烷基吡啶(CPC)和溴化十六烷基三甲铵(CTMAB)改性的有机膨润土吸附处理水中的苯胺,研究了两种有机膨润土吸附处理苯胺的性能及适宜条件.结果表明,有机膨润土对苯胺的去除率比原土增大了十几倍,CTMAB-膨润土、CPC-膨润土及原土的饱和吸附容量分别为130mg/g、87.5mg/g及37.5mg/g.     

CTAB改性膨润土制备及其对海洋溢油的吸附

利用室内吸附实验,以钙基膨润土和改性后的CTAB-膨润土为研究对象,研究了改性前后的膨润土在海洋环境条件下对石油的吸附性能。结果表明,CTAB已经成功地插层到钙基膨润土层间,使其表面形貌更加蓬松,层间距增大为2.04 nm,改性后膨润土由亲水性变为疏水性。改性前后的膨润土对海洋溢油的吸附率均随着膨润土浓度的增加及粒径的减小而增加,改性后膨润土的吸油率比改性前提高了13.1%,最高达到59.5%。临界颗粒物浓度为1 000 mg·L~(-1),最佳颗粒物粒径范围为100μm。CTAB-膨润土对委内瑞拉原油的吸附过程较好地符合准二级动力学模型和Freundlich吸附等温线模型,吸附的最佳时间为240 min,最佳温度为30℃,饱和吸附量约为526 mg·g~(-1)。改性前后的膨润土在海洋环境条件下对石油的吸附性能有明显变化,CTAB-膨润土对海洋溢油的吸附优势较为显著。     

天然海泡石-二乙基二硫代氨基甲酸钠复合体对土壤中镉的钝化机制

通过材料的表征、吸附实验及钝化实验,探讨了天然海泡石-二乙基二硫代氨基甲酸钠复合体(SEP-DDTC)对土壤中镉的钝化效果和机制。结果显示,SEP-DDTC与镉的反应机制除了静电吸附、离子交换吸附和羟基配位吸附外,还存在CSS—基团螯合配位吸附作用。海泡石改性后对镉的饱和吸附容量明显提高;在2种土壤中,添加0.10%(质量分数)SEP-DDTC能够不同程度地降低土壤中有效态镉含量,有效态镉含量分别比对照降低59.4%、18.8%。表明SEP-DDTC是一种潜在的土壤重金属镉修复材料。     

水溶性巯基壳聚糖对污染土壤吸附态汞的解吸作用研究

用两种巯基化试剂半胱氨酸(Cys)和硫代乙醇酸(Thi)与壳聚糖(CTS)反应,制备了两种水溶性巯基壳聚糖,即Cys-CTS和Thi-CTS,对比研究了这两种巯基壳聚糖与CTS对被染毒土壤中吸附态汞的提取能力.结果表明,Thi-CTS在pH=3、质量浓度为0.5g/L、用量为20 mL的条件下.对汞的提取率为59.44%,相同条件下CTS和cys-CTS对汞的最高提取率只有31.81%和10.15%.     

Enhancement of phenanthrene adsorption on a clayey soil and clay minerals by coexisting lead or cadmium

Phenanthrene is commonly present together with heavy metals at many contaminated sites. This study investigated the influence of coexisting lead (Pb²⁺) or cadmium (Cd²⁺) on phenanthrene adsorption on soils. Batch experiments were conducted under different geochemical conditions including pH, mineral structure, organic matter content, and varying amounts of heavy metals. The results showed that the presence of heavy metals in solution at a fixed pH of 5.8 ± 0.1 enhanced phenanthrene adsorption, the extent of which was closely related to the concentrations and the electro-negativity of the metals. The enhancement on phenanthrene adsorption was positively correlated to the amount of adsorbed metals. Although Cd²⁺ is a softer Lewis acid, Pb²⁺ displayed a more significant effect as it was adsorbed to a greater extent on the soil surfaces. Thus, density of cation accumulation appears to be more influential than metal softness in enhancing phenanthrene adsorption. Moreover, with a portion of organic matter removed by heating at 550 °C, there was a stronger enhancement of phenanthrene adsorption by coexisting Pb²⁺, indicating an increasingly dominant mechanisms associated with Pb²⁺ at a lower organic matter content. Similar enhancement phenomenon was observed on bentonite and kaolinite, probably resulting from the cation-π bonding between the adsorbed soft metal cations and the aromatic ring of phenanthrene in solution. The desorption experiments further suggested that the bonding of phenanthrene adsorption was strengthened in the presence of Pb²⁺ and that a larger proportion of adsorbed phenanthrene remained on the soils (residual fraction) even after sequential methanol extractions. Further spectroscopic analyses and surface characterization are required to provide direct evidence of the formation and relative significance of cation-π bond for phenanthrene adsorption.     

液/固体系中硅藻土对Pb2+和Cd2+的吸附机制

为了提高硅藻土在重金属废水处理上的应用水平,采用静态吸附实验考察了液/固体系中硅藻土对Pb2＋、Cd2＋的吸附影响因素、吸附等温线和吸附动力学属性。结果表明,随着投加量的减少,离子初始浓度的提高,pH值的增大,吸附作用时间的延长,硅藻土对Pb2＋、Cd2＋吸附量不断上升;硅藻土对Pb2＋、Cd2＋的等温吸附都符合Langmuir模型,硅藻土对Pb2＋、Cd2＋最大吸附量分别为10.428 mg/g和7.916 mg/g,硅藻土对Pb2＋具有更好的吸附能力;Pb2＋具有较低的水合自由能,更容易脱去水膜与硅藻土孔道内的活性基团发生吸附作用;双常数扩散方程可以很好地描述硅藻土对Pb2＋、Cd2＋的吸附动力学属性,硅藻土对Cd2＋有较快的吸附速率。     

Removal of heavy metal ions from wastewater by a novel HEA/AMPS copolymer hydrogel: preparation, characterization, and mechanism

This study aims to synthesize 2-hydroxyethyl acrylate (HEA) and 2-acrylamido-2-methylpropane sulfonic (AMPS) acid-based hydrogels by gamma radiation and to investigate their swelling behavior and heavy metal ion adsorption capabilities. The copolymer hydrogels prepared were characterized via scanning electron microscopy, Fourier transformed infrared spectra, thermal gravimetric analysis, and X-ray photoelectron spectroscopy. The research showed that the copolymer hydrogel was beneficial for permeation due to its porous structure. In addition, the experimental group A-2-d [70 % water volume ratio and (n (AMPS)/n (HEA))?=?1:1] was an optimal adsorbent. The optimal pH was 6.0 and the optimal temperature was 15 °C. Pb²⁺, Cd²⁺, Cu²⁺, and Fe³+ achieved adsorption equilibriums within 24 h, whereas Cr³⁺ reached equilibrium in 5 h. Pb²+, Cd²⁺, Cr³⁺, and Fe³⁺ maximum load capacity was 1,000 mg L^?1, whereas the Cu²⁺ maximum capacity was 500 mg L^?1. The priority order in the multicomponent adsorption was Cr³⁺>Fe³⁺>Cu²⁺>Cd²⁺>Pb²⁺. The adsorption process of the HEA/AMPS copolymer hydrogel for the heavy metal ions was mainly due to chemisorption, and was only partly due to physisorption, according to the pseudo-second-order equation and Langmuir adsorption isotherm analyses. The HEA/AMPS copolymer hydrogel was confirmed to be an effective adsorbent for heavy metal ion adsorption.     

原位帽封材料对水体中Pb(Ⅱ)与Cd(Ⅱ)静态吸附

用无纺布包裹珊瑚和丙烯酸树脂制成帽封材料,将底泥中重金属离子原位固定的同时吸附水体中的重金属离子pb2和Cd2.通过红外光谱,电镜扫描和火焰原子吸收仪器来分析该帽封材料的吸附性能.通过改变pH值,吸附剂投放量来检测其吸附效果.结果表明,该帽封材料在pH等于5的时候,Cd2最大吸附量达到434.67 mg/g,pb2+最大吸附量达到524.27 mg/g.pH和吸附剂量保持不变,随着底物浓度增加吸附量也增加;电镜扫描图和红外光谱图表明,该材料能很好地吸附重金属离子.     

硅烷化改性沸石对重金属离子的吸附性能

制得一种用于重金属废水处理的新型硅烷化改性沸石吸附剂,成本低、效果显著且稳定。通过对改性沸石表征,分析了改性对沸石结构的影响。结果表明,改性一定程度降低了原沸石的晶体特征,但基本上保持了其结构组成;硅烷化改性成功地在沸石上接枝了氨基。对硅烷化沸石的特性研究,得出硅烷化沸石对Ni2+、Cu2+、Zn2+和Pb2+吸附最佳投加量为1、1、1.6和0.6 g/L,且此时对4种离子的去除率也较好;吸附动力学研究得出,其吸附过程可用二级动力学方程较好地拟合;吸附达到平衡时,4种金属离子的平衡吸附量分别为11.23、17.41、15.45和59.42 mg/g;硅烷化沸石对金属离子的吸附行为更符合Langmuir模型,为化学吸附;在酸性条件下(pH=2～6),硅烷化沸石仍保持一定的吸附能力,具有一定的耐酸性。     

三乙二醇二甲基丙烯酸酯为交联剂制备的高吸水树脂对重金属的吸附

以前期工作中合成的树脂PAANa-TE为吸附剂进行重金属吸附测试,考察吸附剂用量、丙烯酸中和度、吸附时间、溶液pH、初始浓度和吸附温度对树脂吸附重金属离子Cu2+、Pb2+、Cr3+和Co2+性能的影响,用原子吸收分光光度计测定了树脂吸附Cu2+、Pb2+、Cr3+和Co2+后的残留浓度,树脂对4种金属离子的吸附容量分别为21.59、2.39、5.66和4.98 mmol/g,吸附容量大小为Cu2+Cr3+Co2+Pb2+,吸附速率顺序为Cr3+Pb2+Cu2+Co2+。结果表明,该树脂对高浓度重金属离子有较快速,高效率的吸附,吸附过程在100 min左右吸附容量达到最大,并用不同浓度的酸对吸附重金属离子的树脂进行脱附处理,脱附量很小,据此可考虑进一步对金属离子进行回收处理。且脱附率较低,因此,可对工业化和城市化进程所产生的各种化学形态的重金属水体污染物造成的生态环境和质量问题起到重要的改善作用。     

Multi-component adsorption of copper,nickel and zinc from aqueous solutions onto activated carbon prepared from date stones

The removal of Cu²⁺, Ni²⁺, and Zn²⁺ ions from their multi-component aqueous mixture by sorption on activated carbon prepared from date stones was investigated. In the batch tests, experimental parameters were studied, including solution pH, contact time, initial metal ions concentration, and temperature. Adsorption efficiency of the heavy metals was pH-dependent and the maximum adsorption was found to occur at around 5.5 for Cu, Zn, and Ni. The maximum sorption capacities calculated by applying the Langmuir isotherm were 18.68 mg/g for Cu, 16.12 mg/g for Ni, and 12.19 mg/g for Zn. The competitive adsorption studies showed that the adsorption affinity order of the three heavy metals was Cu²⁺?>?Ni²⁺?>?Zn²⁺. The test results using real wastewater indicated that the prepared activated carbon could be used as a cheap adsorbent for the removal of heavy metals in aqueous solutions.     

Competitive biosorption of lead, cadmium, copper, and arsenic ions using algae

The present study aims to evaluate the competitive biosorption of lead, cadmium, copper, and arsenic ions by using native algae. A series of experiments were carried out in a batch reactor to obtain equilibrium data for adsorption of single, binary, ternary, and quaternary metal solutions. The biosorption of these metals is based on ion exchange mechanism accompanied by the release of light metals such as calcium, magnesium, and sodium. Experimental parameters such as pH, initial metal concentrations, and temperature were studied. The optimum pH found for removal were 5 for Cd²⁺ and As³⁺ and 3 and 4 for Pb²⁺ and Cu²⁺, respectively. Fourier transformation infrared spectroscopy analysis was used to find the effects of functional groups of algae in biosorption process. The results showed that Pb²⁺ made a greater change in the functional groups of algal biomass due to high affinity to this metal. An ion exchange model was found suitable for describing the biosorption process. The affinity constants sequence calculated for single system was K _Pb > K _Cu > K _Cd > K _As; these values reduced in binary, ternary, and quaternary systems. In addition, the experimental data showed that the biosorption of the four metals fitted well the pseudo-second-order kinetics model.     

木粉/壳聚糖接枝丙烯酸-丙烯酰胺吸附树脂对二元重金属离子溶液中Pb2+的吸附

采用自制木粉/壳聚糖接枝丙烯酸-丙烯酰胺吸附树脂R1、R2、R3对二元金属离子Cu2 +/pb2和Zn2+/pb2+溶液中的吸附性能进行了较系统考察.pb2+离子溶液中存在竞争离子Cu2+、Zn2+时,随竞争离子浓度增加,3种吸附树脂R1、R2、R3对pb2+的吸附量明显下降,而竞争离子吸附量显著增加.二元溶液中各金属离子浓度相同时,3种树脂对竞争离子Cu2+、Zn2+的吸附量大于对pb2+的吸附量;各溶液中分别加入NaCl及NaNO3、尿素后,对pb2+离子的吸附量下降迅速.随吸附树脂用量增加,竞争离子Cu2+、Zn2+的吸附量逐渐减小,pb2+的吸附量在吸附树脂用量0.10 g/L(Zn2 +/pb2+溶液)或0.15 g/L(Cu2+/pb2+溶液)时出现最大值.溶液pH值对树脂吸附性能有显著影响.3.0＜pH＜5.O时,3种树脂对竞争离子和pb2+的吸附量快速增大;5＜ pH ＜9时,树脂对竞争离子和pb2+的吸附量基本不变;9＜pH＜ll时,树脂对pb2+的吸附量减小,而对竞争离子的吸附量或增大或减小.     

胺基树脂的合成及对水中重金属离子的吸附特征

研究了使用氯甲基化聚苯乙烯交联微球为前驱体与二乙烯三胺经回流反应合成胺基树脂及其对水中Cd2+和Ni2+的吸附特征。结果表明,胺基官能团成功地嫁接到树脂表面,胺基含量为5.6 mmol/g。胺基树脂对Cd2+和Ni2+的吸附等温线表明,温度的升高有利于吸附,且吸附等温线都符合Langmuir模型。pH值对吸附的影响较大,最佳吸附pH值范围为4~6。2种金属离子在胺基树脂上的吸附都符合准二级动力学方程。