纯蒙脱石吸附Zn~（2＋）的研究

[目的]探索纯蒙脱石处理含锌废水的因素与效果。[方法]从蒙脱石提纯入手,进行纯蒙脱石处理含锌废水的试验研究,探讨纯蒙脱石对含锌废水处理效果的影响因素,确定纯蒙脱石去除水中Zn2＋的工艺条件,并研究纯蒙脱石对Zn2＋的吸附等温曲线。[结果]纯蒙脱石对含锌废水处理效果主要受振荡速度、吸附时间、溶液pH值和投加量等因素影响。温度为30℃时纯蒙脱石对Zn2＋的吸附等温曲线更符合Langmuir方程和BET方程,相关系数均为0.986 9,最大吸附容量39.00 mg/g。在该试验条件下,纯蒙脱石对水中Zn2＋（20ml,Zn2＋浓度均为50 mg/L）达到最佳去除效果时的工艺条件为：振荡速度150 r/min,吸附时间60 min,溶液pH值6.10,此条件下Zn2＋去除率达到85.3%。[结论]该研究为应用蒙脱石开发污水处理新材料提供了科学依据。     

吸附去除水产养殖中氨氮研究进展

介绍了吸附去除水产养殖中氨氮的重要性和优点,讨论了水的pH值、所含金属离子和有机物对吸附去除氨氮效果的影响,对常用的活性炭吸附剂、树脂吸附剂、沸石吸附剂和其他矿石、废弃物吸附剂的改良研究进行了比较,指出了其存在的一些问题,并对研究方向进行了展望。     

Magnetically modified spent grain for dye removal

Spent grain, the major by-product of the brewing industry, was magnetically modified by contact with water-based magnetic fluid. The prepared material has been used as a new inexpensive magnetic adsorbent for the removal of water-soluble dyes. The dye adsorption could be described both with the Langmuir and Freundlich isotherms. The maximum adsorption capacities reached the value up to 72.4 mg of dye (Bismarck brown Y) per g of dried magnetically modified spent grain.     

西施柚果发育过程中金属营养元素生理研究

研究西施柚果实发育过程K、Ca、Mg、Zn、Cu、Mn、Fe共7种金属营养元素的含量与分布、吸收规律及其与活性氧代谢的相关性.结果表明:(1)4～6月、6～8月和8～10月分别是果皮迅速生长期、果肉迅速生长期和果实转色成熟期.(2)果皮和果肉中K、Mg、Zn、Cu、Mn、Fe的含量均随果实的发育总体呈递减规律(果皮中Ca的含量相反),但7种元素的吸收总量则不断增加.K含量位居7种元素之首.K、Zn、Fe以果肉居多,Ca、Mg、Mn主要分布在果皮,Cu在果皮果肉中的含量相当.(3)7种元素的累积主要集中在6～8月果肉迅速增长期,K、Ca和Fe在10月果实成熟期也有较大的吸收.K的吸收率与单果重增长率呈极显著正相关,Ca和Fe与单果重、Mg和Cu与果肉直径呈显著正相关.(4)7种元素中K与其它元素的相关性显著率较高,Ca和Cu以负相关为主.(5)Mn和K与活性氧代谢指标相关性较显著,其次是Zn、Fe和Mg,Ca和Cu均不显著.     

Preparation of Aspergillus niger Mycelium-chitosan Biosorbent and Its Cu2+ Adsorption Mechanism北大核心CSCD

The waste Aspergillus niger mycelium and chitosan were cross-linked by epichlorohydrin and then solidified sodium tripolyphosphate to prepare the Aspergillus niger mycelium-chitosan biosorbent for Cu2+. The effects of adsorption time, pH value, temperature, the initial concentration of Cu2+ and the amount of biosorbent on the adsorption efficiency were investigated. Kinetics, intragranular diffusion model, adsorption isotherm equation, thermodynamic model were used to fit the experimental data. The results showed that the adsorption rate increased by increasing the adsorption temperature, adsorption time and pH value. The adsorption rate of Cu2+ reached 99.42% at the adsorption conditions of 0.4 g Aspergillus niger mycelium-chitosan biosorbent, adsorption time 180 min, adsorption temperature 50 ℃, mass concentration of Cu2+ 20 mg/L. The adsorption process conformed to the Freundlich isotherm model. The adsorbed Gibbs free energy became negative, and ΔHθ were ΔSθ are 6.104 2 kJ/mol and 45.258 1 J/(mol·K), respectively, ie the adsorption was a spontaneous endothermic process. Kinetic data analysis showed that the adsorption of Cu2+ by Aspergillus niger mycelia-chitosan biosorbents fitted quasi-second-order kinetic model. © 2018, Editorial Board of «Chemistry and Industry of Forest Products». All right reserved.     

Biosorption of macronutrients by Brazilian tropical peats

The objective of this work was to evaluate the adsorption of macronutrients calcium, potassium, magnesium, nitrogen, and phosphorus in two Brazilian tropical peat samples, investigating the effect of pH and determining the kinetics of the adsorption process. Two different Brazilian tropical peat samples were characterized using FTIR, TG, and SEM techniques. Different pH conditions were tested, as well as different mass concentrations of the peats. Differences in the chemical structures of the peat samples directly influenced the adsorptive capacities for the macronutrients. The adsorptive capacity for nitrogen was highest at pH 3, while the best adsorption of calcium and potassium was obtained at pH 6. The best fit to the data was provided by the pseudo-second-order model, which confirmed the rapid adsorption of calcium by both peats.     

风化煤对农田土壤重金属汞的钝化修复

风化煤钝化修复土壤主要是其活性官能团与重金属发生络合、鳌合等一系列反应,进而降低重金属在土壤中的可迁移性和生物有效性,以达到修复土壤的目的。本文系统研究了风化煤对重金属汞(Hg)的吸附特性及其对Hg在土壤中径向迁移和生物可利用性的影响。结果显示:风化煤对酸碱有一定的缓冲作用,pH对Hg的平衡吸附量影响不大,最大吸附量为8.19 mg/g,该吸附为吸热反应。风化煤对Hg的吸附作用采用Freundlich方程描述较好,为多分子层吸附,吸附动力可用拟二级速率方程描述。土柱试验中风化煤用量为1、2、4、8 g时,淋溶液中Hg含量分别下降2.62、1.66、1.10、0.70μg/g,风化煤的使用可以降低Hg从土壤向溶液的迁移。盆栽试验进一步验证了风化煤对土壤中Hg迁移的阻控作用,其中添加风化煤黄壤中移栽30 d和70 d收获的白菜叶中Hg含量较未添加风化煤黄壤中下降了0.14μg/kg和0.09μg/kg;添加风化煤和外源Hg黄壤中Hg含量是未添加风化煤黄壤的2.4倍,而收获的30、70d小白菜叶中Hg含量前者分别为0.53、0.82μg/kg,后者分别为0.35、0.48μg/kg,理论上可认为前者较后者分别下降了0.31、0.33g/kg。可见,风化煤实现了对土壤中Hg的吸附、钝化,减缓了其生物可利用性,是一种廉价高效的环境友好型钝化剂。     

Cd/Cu/Pb对磺胺嘧啶在土壤中吸附迁移的影响

通过室内批平衡实验和土柱出流实验,探讨了不同浓度镉(Cd)及相同浓度的Cd、铜(Cu)、铅(Pb)对磺胺嘧啶在土壤中吸附、迁移的影响,并分别用Freundlich、Langmuir、Linear方程及Hydrus-1D中的单点和两点吸附模型模拟其在土壤中的吸附、运移过程。结果表明:当Cd浓度为10.0mg·kg~(-1)时促进磺胺嘧啶的吸附;Cd浓度为1.0、300.0mg·kg~(-1)时抑制磺胺嘧啶吸附;Cd浓度为100.0 mg·kg~(-1)时对磺胺嘧啶的吸附无影响;300 mg·kg~(-1)的Cd、Cu、Pb存在时,磺胺嘧啶吸附量大小顺序为:CdCuPb。土柱出流实验中,当Cd浓度为10.0mg·kg~(-1)时,磺胺嘧啶在土柱中的迁移速度最慢,其他浓度对迁移影响不明显;Cd、Cu、Pb相比较而言,Cu存在时磺胺嘧啶的迁移最快,Cd存在时迁移最慢。在对静态吸附特征的拟合过程中,Linear方程拟合效果最好,决定系数R~2均在0.98以上;Hydrus-1D模拟时,两点模型可更好地拟合磺胺嘧啶的运移特征,R~20.907,均方根误差RMSE0.051,瞬时吸附f所占分数较高,说明磺胺嘧啶在迁移过程中存在较大程度的瞬时吸附。     

改性活性炭吸附咪唑类离子液体的效果

[目的]通过氧化处理提高活性炭吸附量。[方法]活性炭的表面化学性质可以直接影响活性炭对离子液体的吸附,采用过氧化氢、硝酸、过硫酸铵氧化活性炭(F300),改变其表面的官能团含量,合成过氧化氢改性活性炭(HF300)、硝酸改性活性炭(NF300)、过硫酸铵改性活性炭(SF300),研究其对氯化1-丁基-3-甲基咪唑(Bmimcl)和氯化1-辛基-3-甲基咪唑(Omimcl)的吸附影响。[结果]HF300、NF300、SF300表面的含氧官能团显著增加;HF300、NF300、SF300中SF300对含亲水性阳离子的Bmimcl的吸附效果最佳且提升最为显著,吸附容量由TF300的0.19 mmol/g增加到0.29 mmol/g;HF300、NF300、SF300对含疏水性阳离子的Omimcl的吸附无明显变化。SF300对Bmimcl和Omimcl的吸附均符合Freundlich模型;SF300对Bmimcl和Omimcl的吸附符合准二级动力学,Bmimcl在SF300上的准二级动力学速率常数为0.016 3 g/(mg·min),Omimcl在SF300上的准二级动力学速率常数为0.002 2 g/(mg·min)。无机阳离子(Na~+,Ca~(2+))会抑制SF300对Bmimcl和Omimcl的吸附,且Ca~(2+)的抑制效果强于Na~+。SF300对Bmimcl和Omimcl的吸附量随pH的升高呈现出先升高后变低的变化趋势,对Bmimcl和Omimcl的吸附量分别在pH=7和5时达到最大。[结论]氧化处理可以提高活性炭的吸附量。