泥炭吸附法去除废水中重金属

介绍了天然廉价矿物泥炭的物理化学性质,综述了泥炭的改性方法及其对多种重金属离子的吸附容量．分析了pH、改性方法、竞争离子浓度等因素的影响。并对泥炭吸附重金属离子的机理和规律进行了总结．其吸附机理有离子交换、络合、表面吸附、化学吸附等四种,吸附一般符合Langmuir吸附等温式或Freundlich吸附等温式。最后展望了泥炭在重金属废水处理中的应用前景,提出了一些建议。     

泥煤对镍吸附作用的研究

在介质pH=6～8左右时,泥煤吸附镍的吸附量最大,在pH〈6时,随着介质pH值的升高,吸附量增加。介质的离子强度升高可以使泥煤对镍的吸附量迅速降低。温度升高可以使泥煤吸附镍的量降低。吸附液镍浓度升高,泥煤吸附镍量增加。泥煤对溶液中Ni^2＋的吸附符合Freundlich吸附等温方程,泥煤对Ni^2＋的吸附过程是比较快的。     

Development of a first-order kinetics-based model for the adsorption of nickel onto peat

The use of peat for the removal of nickel from aqueous solutions has been investigated at various pH values by means of static conditions. The present research shows that the ability of Ni to hind to peat increases as the pH value increases. The solutions reach adsorption equilibrium rapidly. A reasonable kinetic model, first-order in nickel concentration, has been developed and fitted to the adsorption of nickel (Ⅱ) onto peat. The first-order model provides a good correlation to the experimental data. The characteristic parameters of the Langmuir isotherm were determined at various temperatures. The relationship between kinetics and equilibrium isotherms was established through the forward- and backward-rate-constants, k and k2, and the equilibrium constant, K.     

Geochemistry of two peats suitable for medical uses and their behaviour during leaching

The compositional characteristics of two peats, from Austria and Italy, have been studied. The Massaciuccoli peat shows a high quantity of trace elements (Br, Cd, Mo, Se, U, As and Sb) with respect to the average shale, whereas the Neydharting peat contains more Br, Se and U. Since the therapeutic properties of peats are broad and interesting, the mobility of trace elements (As, Cd, Hg, Pb, Sb, Se, Te and Tl) used for pelotherapy, during water leaching and after Na exchange, have been checked. The data concerning the leaching procedure indicate that the analysed peats are rather stable materials under laboratory conditions. Although the concentration of some toxic elements (As, Se, Cd and Hg) in bulk peats are of the same order of magnitude as in muds used in pelotherapy, the release after similar leaching is lesser. The higher release from muds could be explained by the high exchange capacity of smectite minerals. These minerals are characterised by low cation selectivity because the chemical interactions between smectite and sorbed species is mainly ionic. On the other hand, the cation–organic matter interactions can establish a higher degree of covalent bonds, that are more stable during the interactions developed with leaching. An additional possibility can be considered taking into account the genetic conditions of peat formation. In the upper part, the acidic and oxidising conditions cause the depletion of mobile elements. This process can be seen as a natural cleaning, which occurs under relatively strong conditions compared to the use during medical treatments.     

The kinetics of sorption of basic dyes from aqueous solution by sphagnum moss peat

The kinetics of sorption of three basic dyes, namely, Chrysoidine (BO2), Astrazon Blue (BB3) and Astrazone Blue (BB69) onto sphagnum moss peat have been investigated. The study focuses on the application of three sorption kinetic models for predicting the uptake of basic dyes. The sorption behaviour is found to be second order, based on the assumption of a pseudo-second order mechanism. The rate constant of sorption, the equilibrium capacity and initial sorption rate with the effect of various peat doses and initial dye concentrations have also been predicted.