Chen Yunnen

Comparison for Adsorption Modeling of Heavy Metals (Cd, Pb, Cu, Zn) from Aqueous Solution by Bio-Formulation

The demand for effective and inexpensive sorbents is increasing in response to the widespread recognition of the deleterious health effects of heavy metals exposure through aqueous solutions. An adsorbent, bio-formulation (BF), was prepared by agricultural waste. The maximal biosorption removal of cadmium (II), lead(II), copper(II), zinc(II) on BF are 99.4, 99.8, 97.6, 98.3% at pH 8, 5, 5, 7, respectively. Freundlich adsorption isotherm is well fitted to the experimental data. The adsorption kinetics of heavy metals reveal that adsorption of heavy metals is very rapid within the first 30 min and equilibrium time is independent of initial concentration. The adsorption process follows second-order sorption kinetics. The biosorption mechanism may be cation exchange effect.

The mechanism of ion exchange and adsorption coexist on medium–low concentration ammonium–nitrogen removal by ion-exchange resin

In this study, the removal of medium–low concentration ammonium–nitrogen () from waters and wastewaters on D113 resin was investigated with respect to pH, initial concentration, temperature and contact time. The equilibrium of on D113 resin reached in 20–30 min. The process of removal by D113 resin fitted Langmuir isotherm well. The pseudo second-order kinetic and intra-particle diffusion models were used to investigate the kinetic data of on D113 resin. The desorption solution can be returned to production after pretreatment. The mechanism of removal of by D113 resin was coexistence of adsorption and cation exchange. When the dosage of D113 resin was 5 g L−1, pH 6, contact 30 min at room temperature, initial concentration being 116 mg L−1 in rare earth metallurgical wastewater was reduced to 13 mg L−1 after adsorption treatment.

Equilibrium and Kinetics of Arsenic (V) Sorption by Bone Char

Arsenic is a toxic element and may be found in natural waters as well as in industrial waters, which requires proper treatment before its use as drinking water. Present investigation aims to remove arsenate ions [As(V)] by bone char. Effect of solution pH, initial concentration, and contact time has been investigated. Kinetics reveal that removal of As(V) ion by bone char is very rapid in the first 30 min and equilibrium time in independent of initial As(V) concentration. The arsenate removal is strongly dependent on pH. Equilibrium studies show that As(V) ions have high affinity towards bone char at pH 10. Both Freundlich and Langmuir adsorption isotherms are well fitted to the experimental data. The results suggests that adsorption of As(V) removal on bone char is complex mechanism where both surface adsorption and intraparticle diffusion contribute to the rate determining step.