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Abstract-The effects of three physical pretreatment methods (water bath, ultrasound and microwave) on the cellulose recovery of water hyacinth were investigated in this study. Before treatment, cellulose and hemicellulose content of dried water hyacinth sample was 36.04%. After treating by ultrasound (70 o C for 1 h) at a ratio of deionized water (DIW) (mL) to dried sample (g) of 10:1, cellulose and hemicellulose content in the treated sample was 57.70.65 %. The highest yield of cellulose and hemicellulose (58.190.59%) obtained by water bath treament at 100 o C for 1 h whereas the cellulose and hemicellulose yield was 60.420.07% attained by microwave pretreatment (350W, 10 min at a ratio of DIW (mL) to dried sample (g) of 10:1). Therefore, among three pretreatment methods, microwave assisted DIW pretreatment presented the best efficiency on cellulose recovery. The outcome showed that microwave assisted DIW pretreated water hyacinth is a promising raw material for bioethanol production. The effects of these treatments on the composition and structure of water hyacinth were studied by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM).Index Terms-Water hyacinth, Eichhornia crassipes, cellulose recovery, ultrasound, microwave and water bath.

This work investigated the speciation and solubility of indium (In) and its flotation separation from aqueous solution. Lowest theoretical In solubility was predicted for pH 5.5−8.5, and the solubility increased as it became more acidic or more alkaline. Experimentally, 20 mg/L of In completely dissolved at pH < 3.0, which agreed with theoretical prediction. At pH 3.6−9.9, In showed slightly higher solubility than predictions. There was good agreement at pH > 9.9. Flotation reaction was described by pseudo-first-order kinetic model and its reaction rate increased with increasing nitrogen flow rate. The results indicated that pH played a key for the flotation process. As pH increased from 4.0 to 6.8, removal efficiency rose from 65.0% to 95.8% when applying surfactant SDS as collector. The efficiency decreased to 56.7% at pH 9.9. Lower removal efficiency was found once using CTAB. Electrostatic interaction between collector with both soluble and colloidal In was the main mechanism for In flotation.

Flotation separation of strontium (Sr) from wastewater via phosphate precipitation was investigated. While 37.33% of Sr precipitated at highly alkaline pH in the absence of PO, it completely precipitated as Sr(PO) at a molar ratio ([PO]:[Sr]) of 0.62 at a lower pH value. The presence of Ca hindered Sr precipitation, yet it could be overcome by increasing the PO dose. Sodium dodecyl sulfate (SDS) was a better collector for dispersed air flotation of Sr(PO) than cetyl trimethyl ammonium bromide, or mixed collector systems of SDS and saponin. The highest separation efficiency of 97.5% was achieved at an SDS dose of 40 mg/L. The main mechanism in the precipitate flotation is adsorption of anionic SDS on the positively charged surface of colloidal Sr(PO) via electrostatic interaction. SDS enhanced the aggregation of Sr(PO) precipitates as the size increased from 1.65 to 28.0 μm, which was beneficial to separation as well.