He Ziqi, Traina Samuel J, Weavers Linda K
Department of Civil and Environmental Engineering and Geodetic Science, The Ohio State University, Columbus, Ohio 43210, USA.
Environ Sci Technol. 2007 Feb 1;41(3):773-8. doi: 10.1021/es0613299.
To investigate the sonochemical dissolution of cinnabar, sulfur oxidation products (S(ox)) and dissolved Hg(II) released into the aqueous solution were determined. Detected S(ox), in the presence of ultrasound suggests that dissolution of cinnabar occurred. Terephthalic acid (TA) used to scavenge *OH in bulk solution formed from sonication showed that oxidative dissolution occurred in both the bulk solution and the interfacial areas of cavitation bubbles. Dissolved S(-II) was not detected, and SO4(2-) was the main S(ox) indicating that the formation of S(-II) from cinnabar by physical and thermal effects of sonication was the rate-limiting step. Hg(Il) released was much lower than S species measured. Hg(II) adsorption isotherms indicated that dissolved Hg(II) adsorbed back onto the remaining cinnabar particles lowering Hg(II) release. Ultrasound significantly reduced cinnabar particle size and increased surface area, leading to higher Hg(ll) adsorption. In addition, the cinnabar surface isoelectric point (IEP) increased after sonication, indicating adsorption of Hg(II) and/ or mineral phase transformation from cinnabar to metacinnabar. The presence of humic acid (HA) and ultrasound enhanced cinnabar dissolution and greatly increased the dissolved Hg(ll) concentration due to the synergistic effects of ultrasound and HA.
为了研究朱砂的声化学溶解过程，测定了释放到水溶液中的硫氧化产物（S(ox)）和溶解的Hg(II)。在超声作用下检测到的S(ox)表明朱砂发生了溶解。用于清除超声处理形成的本体溶液中*OH的对苯二甲酸（TA）表明，氧化溶解在本体溶液和空化气泡的界面区域均发生。未检测到溶解的S(-II)，且SO4(2-)是主要的S(ox)，这表明超声的物理和热效应使朱砂形成S(-II)是限速步骤。释放的Hg(II)远低于所测的硫物种。Hg(II)吸附等温线表明溶解的Hg(II)会重新吸附到剩余的朱砂颗粒上，从而降低Hg(II)的释放。超声显著减小了朱砂颗粒尺寸并增加了表面积，导致更高的Hg(II)吸附。此外，超声处理后朱砂表面等电点（IEP）升高，表明有Hg(II)吸附和/或从朱砂到黑辰砂的矿物相转变。腐殖酸（HA）的存在与超声协同作用，增强了朱砂的溶解并大大提高了溶解的Hg(II)浓度。
