Boron removal and recovery from concentrated wastewater using a microwave hydrothermal method

JOURNAL OF HAZARDOUS MATERIALS

卷:186

Article

Tsai, Hao-Cheng¹  Lo, Shang-Lien¹ 

[1] Natl Taiwan Univ, Grad Inst Environm Engn, Taipei 106, Taiwan

关键词: Boron recovery;    Calcium hydroxide;    Microwave hydrothermal;    Mineralization;   

DOI  :  10.1016/j.jhazmat.2010.12.010

来源: Elsevier

【 摘 要 】

Boron compounds are widely-used raw materials in industries. However, elevated boron concentrations in aqueous systems may be harmful to human and plants. In this study, calcium hydroxide (Ca(OH)(2)) alone and Ca(OH)(2) with phosphoric acid (H3PO4) addition (P-addition) were used to remove and recover boron from wastewater using hydrothermal methods. A microwave (MW) hydrothermal method was used and compared with the conventional heating (CH) method in batch experiments. Physicochemical properties of the precipitates obtained from both methods were analysed by XRD, SEM with EDX and BET. For the case of Ca(OH)(2) alone and the MW method, experimental results showed that boron recovery efficiency reached 90% within 10 min. and crystals of Ca2B2O5 center dot H2O were found in the precipitates as indicated by the XRD analysis. For the case of P-addition and the MW method, boron recovery efficiency reached 99% within 10 min, and calcium phosphate species (CaHPO4 center dot H2O, CaHPO4 and Ca-10(PO4)(6)(OH)(2)) were formed. The experimental results of this study indicate that the required reaction time of the MW method was much less than that of the CH method, and the MW method is an effective and efficient method for boron removal and recovery from concentrated wastewater. (C) 2010 Elsevier B.V. All rights reserved.

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