Thallium (Tl) in industrial wastewater is a public health concern due to its extremely high toxicity. However, there has been limited research regarding Tl removal techniques and engineering practices to date. In this...Thallium (Tl) in industrial wastewater is a public health concern due to its extremely high toxicity. However, there has been limited research regarding Tl removal techniques and engineering practices to date. In this investigation, bench and pilot studies on advanced treatment of industrial wastewater to remove Tl to a trace level were conducted. The treatment process involved a combination of hydroxide precipitation, Fenton oxidation, and sulfide precipitation. While hydroxide precipitation was ineffective for Tl^+ removal, it enabled the recovery of approximately 70%-80% of Zn as Zn hydroxide in alkaline conditions. The Fenton process provided good Tl removal (>95%) through oxidation and precipitation. Tl was then removed to trace levels (< 1.0 μg/L) via sulfide precipitation. Effective removal of other heavy metals was also achieved, with Cd < 13.4 μg/L, Cu < 39.6 μg/L, Pb < 5.32 μg/L, and Zn < 357 μg/L detected in the effluent. X-ray photoelectron spectroscopy indicated that T12S precipitate formed due to sulfide precipitation. Other heavy metals were removed via the formation of metal hydroxides during hydroxide precipitation and Fenton treatment, as well as via the formation of metal sulfides during sulfide precipitation. This combined process provides a scalable approach for the in-depth removal of Tl and other heavy metals from industrial wastewater.展开更多
Nano zero-valent manganese(nZVMn,Mn^0)was prepared through a borohydride reduction method and coupled with different oxidants(persulfate(S2O8^2-),hypochlorite(CIO^-),or hydrogen peroxide(H2O2))to remove thallium(TI)fr...Nano zero-valent manganese(nZVMn,Mn^0)was prepared through a borohydride reduction method and coupled with different oxidants(persulfate(S2O8^2-),hypochlorite(CIO^-),or hydrogen peroxide(H2O2))to remove thallium(TI)from wastewater.The surface of Mn°was readily oxidized to form a core-shell composite(MnOx@Mn°),which consists of Mn°as the inner core and MnOr(MnO,M112O3,and Mn3O4)as the outer layer.When Mn^0 was added alone,effective T1(I)removal was achieved at high pH levels(>12).The Mn-H2O2 system was only effective in T1(I)removal at high pH(>12),while the Mn^0-S2O8^0or Mn0-ClO^-system had excellent T1(I)removal(>96%)over a broad pH range(4-12).The Mn-S2O8 oxidation system provided the best resistance to interference from an external organic matrix.The isotherm of T1(I)removal through the Mn°-S2O8^2-system followed the Freundlich model.The Mn°nanomaterials can activate persulfate to produce sulfate radicals and hydroxyl radicals.Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy suggested that oxidation-induced precipitation,surface adsorption,and electrostatic attraction are the main mechanisms for T1(I)removal resulting from the combination of Mn^0 and oxidants.Mn^0coupled with S2O8^2-/ClO^-is a novel and effective technique for T1(I)removal,and its application in other fields is worthy of further investigation.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 51808144, 41830753, 41673110 and U1612442)Guangdong innovation platform characteristic innovation project (No. 2016KTSCX106)+2 种基金the Guangzhou Education Bureau (No. 1201630390)the Science and Technology Program of Guangzhou (No. 201804010281)the Guangdong natural science foundation (No. 2018A0303130265).
文摘Thallium (Tl) in industrial wastewater is a public health concern due to its extremely high toxicity. However, there has been limited research regarding Tl removal techniques and engineering practices to date. In this investigation, bench and pilot studies on advanced treatment of industrial wastewater to remove Tl to a trace level were conducted. The treatment process involved a combination of hydroxide precipitation, Fenton oxidation, and sulfide precipitation. While hydroxide precipitation was ineffective for Tl^+ removal, it enabled the recovery of approximately 70%-80% of Zn as Zn hydroxide in alkaline conditions. The Fenton process provided good Tl removal (>95%) through oxidation and precipitation. Tl was then removed to trace levels (< 1.0 μg/L) via sulfide precipitation. Effective removal of other heavy metals was also achieved, with Cd < 13.4 μg/L, Cu < 39.6 μg/L, Pb < 5.32 μg/L, and Zn < 357 μg/L detected in the effluent. X-ray photoelectron spectroscopy indicated that T12S precipitate formed due to sulfide precipitation. Other heavy metals were removed via the formation of metal hydroxides during hydroxide precipitation and Fenton treatment, as well as via the formation of metal sulfides during sulfide precipitation. This combined process provides a scalable approach for the in-depth removal of Tl and other heavy metals from industrial wastewater.
基金the National Natural Science Foundation of China(Grant Nos.51808144,51678562,and 41830753)the Science and Technology Program of Guangzhou(Nos.201906010037 and 201804010281)the Guangdong Natural Science Foundation(No.2018A0303130265).
文摘Nano zero-valent manganese(nZVMn,Mn^0)was prepared through a borohydride reduction method and coupled with different oxidants(persulfate(S2O8^2-),hypochlorite(CIO^-),or hydrogen peroxide(H2O2))to remove thallium(TI)from wastewater.The surface of Mn°was readily oxidized to form a core-shell composite(MnOx@Mn°),which consists of Mn°as the inner core and MnOr(MnO,M112O3,and Mn3O4)as the outer layer.When Mn^0 was added alone,effective T1(I)removal was achieved at high pH levels(>12).The Mn-H2O2 system was only effective in T1(I)removal at high pH(>12),while the Mn^0-S2O8^0or Mn0-ClO^-system had excellent T1(I)removal(>96%)over a broad pH range(4-12).The Mn-S2O8 oxidation system provided the best resistance to interference from an external organic matrix.The isotherm of T1(I)removal through the Mn°-S2O8^2-system followed the Freundlich model.The Mn°nanomaterials can activate persulfate to produce sulfate radicals and hydroxyl radicals.Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy suggested that oxidation-induced precipitation,surface adsorption,and electrostatic attraction are the main mechanisms for T1(I)removal resulting from the combination of Mn^0 and oxidants.Mn^0coupled with S2O8^2-/ClO^-is a novel and effective technique for T1(I)removal,and its application in other fields is worthy of further investigation.
