Phosphate adsorption on granular palygorskite: batch and column studies.

A method to prepare granular palygorskite (GPA) was put forward in this research, and its potential use to remove phosphate species from aqueous solution was assessed. Batch experiments were performed to study the adsorption equilibrium and influence of contact time and pH on the adsorption and desorption of phosphate onto GPA in water. The maximum phosphate adsorption capacity of GPA was 13.1 mg/g. Kinetic data revealed that more than 90% of phosphate was adsorbed onto GPA within 2 hours. Phosphate adsorption capacity was 0.10 mg/g in column experiments, and co-existing anions could decrease phosphate removal. The saturated column was regenerated by 0.2 mol/L sodium hydroxide, and the GPA could be reused in phosphate removal. The data obtained from both batch and column studies indicated that GPA could be used effectively to remove phosphate from water.

Characterization of animal manures using mid-infrared photoacoustic spectroscopy.

The feasibility of using Fourier transform mid-infrared photoacoustic spectroscopy (FTIR-PAS) for rapid characterization of animal manures was investigated. Animal manure samples were collected from various places in China, and probabilistic neural networks (PNN) and partial least squares (PLS) were initially applied in the qualitative and quantitative analysis of animal manures, respectively. The animal manures exhibited distinctive bands, specifically around 2900-3700 cm(-1), 1200-1800 cm(-1) and 500-1100 cm(-1). There were numerous differences in the spectra of different animal manures, and manures were successful identified by PNN model; organic matter contents in animal manure were well predicted by PLS model, and the calibration coefficient (R(2)), validation error and RPD (ratio of standard deviation to predicted error) were 0.93, 2.38% and 2.58%, respectively, suggesting the potential application of FTIR-PAS for the fast characterization of animal manures.