http://dns2.asia.edu.tw/~ysho/YSHO-English/1000%20WC/PDF/Pro%20Bio34,%20451.pdf

Pseudo-second order model for sorption processes

http://libir.tmu.edu.tw/bitstream/987654321/43034/1/4.pdf

Review of second-order models for adsorption systems.

A review of potentially low-cost sorbents for heavy metals

http://dns2.asia.edu.tw/~ysho/ysho-english/1000 wc/pdf/wat res34, 735.pdf

The kinetics of sorption of divalent metal ions onto sphagnum moss peat

The kinetics of sorption from a solution onto an adsorbent has been explored theoretically. The general analytical solution was obtained for two cases. It has been shown that at high initial concentration of solute (sorbate) the general equation converts to a pseudo-first-order model and at lower initial concentration of solute it converts to a pseudo-second-order model. In other words, the sorption process obeys pseudo-first-order kinetics at high initial concentration of solute, while it obeys pseudo-second-order kinetics model at lower initial concentration of solute. The theoretical results (derived equations) show that the observed rate constants of pseudo-first-order and pseudo-second-order models are combinations of adsorption and desorption rate constants and also initial concentration of solute. The obtained theoretical equations are used to correlate experimental data for sorption kinetics of some solutes on various sorbents. The predictions of the theory are in excellent agreement with the experimental data.

Kinetic models of sorption: a theoretical analysis.

A pseudo-second order rate equation describing the kinetics of sorption of divalent metal ions on to sphagnum moss peat at various initial metal ion concentrations and peat doses has been developed. The sorption kinetics were followed based on the concentrations of metal sorbed at various time intervals. Results show that chemical sorption processes might be rate-limiting for the sorption of divalent metal ions on to peat during agitated batch contact time experiments. The rate constant, the equilibrium sorption capacity and the initial sorption rate were calculated. From these parameters, an empirical model for predicting the concentrations of metal ions sorbed was derived.

http://dns2.asia.edu.tw/~ysho/YSHO-English/Publications/PDF/Ads%20Sci%20Tec18,%20639.pdf

Study of the Sorption of Divalent Metal Ions on to Peat

Much of the work on the adsorption of metals by low-cost, natural biosorbents has focussed on the uptake of single metals. In practice, wastewaters are polluted with multiple metals. In addition, the kinetics of adsorption, which are important in the design of treatment systems, have largely been neglected. This paper describes the results of an examination into the adsorption by peat of copper and nickel from both mono and bi-solute systems. These showed that, in general, pore diffusion appeared to be the rate-controlling step and that the presence of ‘contaminant’ copper ions reduced the binding of nickel. In fact, the best interpretation which could be placed on the data was that the behaviour of nickel was unusual. The results also showed that the kinetics of adsorption were best described by a second-order expression rather than a first-order model.

Kinetic Studies of Competitive Heavy Metal Adsorption by Sphagnum Moss Peat

The use of sphagnum moss peat for the removal of lead from aqueous solution has been studied in batch experiments. Investigations include the effect of pH and temperature, and kinetics of adsorption. The adsorption equilibria data were found to follow Langmuir models. It was found that the efficiency of lead removal using sphagnum moss peat as adsorbent depended very little either on the reaction temperatures (10 to 40°C) or on the initial pH values (4.0 to 6.0). Kinetic data suggested that the adsorption process was endothermic and pore diffusion was not the only rate-determining step.

D.A.J. Wase

Papers

Study of the Sorption of Divalent Metal Ions on to Peat

Kinetic Studies of Competitive Heavy Metal Adsorption by Sphagnum Moss Peat

Removal of lead ions from aqueous solution using sphagnum moss peat as adsorbent

The Adsorption of Divalent Copper Ions from Aqueous Solution by Sphagnum Moss Peat.