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BACKGROUND The extractable state of soil heavy metal elements is an important index to measure their bioavailability, but its content changes with soil acid-base properties and other environmental conditions. When determining which method to use for the extractable state of soil heavy metal elements, there are more than 7 kinds of extraction reagents involved in relevant standard methods or technical specifications. These include hydrochloric acid of pH=5.8, 0.1mol/L hydrochloric acid, 0.43±0.02mol/L nitric acid, 0.11mol/L acetic acid, 1mol/L ammonium nitrate solution, 0.005mol/L DTPA leaching agent, 0.01mol/L calcium chloride solution. Different scholars have different research conclusions on different extractants. There is no systematic research report on extractants suitable for different soil types. OBJECTIVES To select and determine the general extractant suitable for the extractable state of heavy metal elements in soil with different acid-base properties. METHODS Using typical farming soil samples as the research objective, 7 kinds of extracting agent were used to extract 8 heavy metals (Cd, Ni, Cu, Zn, Cr, Pb, As and Hg). Inductively coupled plasma-mass spectrometry (ICP-MS) was used to determine Cd, Cr, Cu, Pb, Zn, Ni, whereas atomic fluorescence spectrometry (AFS) was used to determine As and Hg. The extraction rates of 7 kinds of extractants were compared, and the effects of soil acid and alkali properties on the extraction rate of heavy metal elements were studied. RESULTS Dilute acid solution had a strong ability of leaching heavy metals from soil, and it was not related to the acidity and alkalinity of the soil. Although the extraction ability of 1mol/L ammonium nitrate solution for cadmium indicated that the activity of cadmium in acidic soil was much higher than that in alkaline soil, its extraction rate of lead in alkaline soil was higher than that of cadmium. The extraction rate of DTPA extractant for soil heavy metal elements was significantly higher than that of 0.01mol/L calcium chloride solution, especially for lead, copper and zinc. Moreover, the extraction rate of DTPA extractant for soil heavy metal elements did not change significantly with soil acid-base properties. 0.01mol/L calcium chloride solution had the highest extraction rate of cadmium in soil, which was closely related to the acid-base properties of soil. CONCLUSIONS 0.01mol/L calcium chloride solution is an ideal general extractant for the extractable state of soil heavy metal elements.

C19H25NO8, monoclinic, P21/n (no. 14), a = 10.149(2) Å, b = 12.338(3) Å, c = 15.898(3) Å, β = 97.58(3)°, V = 1973.2(7) Å3, Z = 4, Rgt(F) = 0.0581, wRref(F2) = 0.1842, T = 293(2) K.

C19H25NO8, monoclinic, P21/n (no. 14), a = 10.149(2) Å, b = 12.338(3) Å, c = 15.898(3) Å, β = 97.58(3)°, V = 1973.2(7) Å3, Z = 4, Rgt(F) = 0.0581, wRref(F2) = 0.1842, T = 293(2) K. [ABSTRACT FROM AUTHOR]

C19H25NO8, monoclinic, P21/n (no. 14), a = 10.149(2) Å, b = 12.338(3) Å, c = 15.898(3) Å, β = 97.58(3)°, V = 1973.2(7) Å3, Z = 4, Rgt(F) = 0.0581, wRref(F2) = 0.1842, T = 293(2) K. [ABSTRACT FROM AUTHOR]

To achieve the "double carbon" (carbon peak and carbon neutrality) target, low-cost CO 2 capture at large CO 2 emission points is of great importance, during which the development of low-cost CO 2 sorbents will play a key role. Here, we chose peanut shells (P) from crop waste as the raw material and KOH and K 2 CO 3 as activators to prepare porous carbons by a simple one-step activation method. Interestingly, the porous carbon showed a good adsorption capacity of 2.41 mmol/g for 15% CO 2 when the mass ratio of K 2 CO 3 to P and the activation time were only 0.5 and 0.5 h, respectively, and the adsorption capacity remained at 98.76% after 10 adsorption-desorption cycle regenerations. The characterization results suggested that the activated peanut shell-based porous carbons were mainly microporous and partly mesoporous, and hydroxyl (O-H), ether (C-O), and pyrrolic nitrogen (N-5) functional groups that promoted CO 2 adsorption were formed during activation. In conclusion, KOH- and K 2 CO 3 -activated P, especially K 2 CO 3 -activated P, showed good CO 2 adsorption and regeneration performance. In addition, not only the use of a small amount of the activator but also the raw material of crop waste reduces the sorbent preparation costs and CO 2 capture costs., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

In this paper, the developments of microfluidic chip-based capillary electrophoresis (CE) for protein separation in recent years are reviewed. Various chip-based CE systems for protein separation based on different CE separation modes are introduced. The approaches to suppress the adsorption of proteins on the surface of microchannel on chips are discussed. The application prospect for chip-based CE in protein separation is also proposed. Forty-seven references are cited.