稳定化海藻酸钠/纳米零价铁生物炭对水中Pb^(2+)、Cu^(2+)和 Cd^(2+)的吸附

Adsorption of Aqueous Pb^(2+),Cu^(2+)and Cd^(2+)Using Stabilized Sodium Alginate/Nano-Zero-Valent Iron Biochar

选用玉米秸秆为原材料,在无氧条件下高温热解浸渍Fe的玉米秸秆粉末,一步合成了负载纳米零价铁的玉米秸秆生物炭(B-nZVI)。通过借鉴生物包埋法,制成海藻酸钠/纳米零价铁生物炭小球(SA/B-nZVI)。通过扫描电子显微镜(SEM)、傅里叶-红外光谱(FT-IR)、X射线衍射(XRD)对SA/B-nZVI进行表征,结果表明,纳米零价铁成功负载于生物炭上,负载的纳米零价铁未发现团聚,纳米零价铁粒径约为27.6 nm,并均匀包埋于海藻酸钠小球中。用SA/B-nZVI研究了水溶液中Pb^(2+)、Cu^(2+)和Cd^(2+)的吸附性能,在最佳吸附条件下,SA/B-nZVI对Pb^(2+)、Cu^(2+)和Cd^(2+)的最大吸附量分别为349、147、106 mg/g。由Langmuir计算出SA/B-nZVI对Pb^(2+)、Cu^(2+)和Cd^(2+)的理论饱和吸附容量分别为351、153、109 mg/g。重复使用5次后,SA/B-nZVI对Pb^(2+)、Cu^(2+)和Cd^(2+)的去除率分别为87%、79%、73%。

We synthesized corn stalk biochar loaded with nano-zero-valent iron(B-nZVI) in one step by high-temperature pyrolysis of corn stover powder impregnated with Feunder anaerobic conditions. Sodium alginate/nano-zero-valent iron biochar pellets(SA/B-nZVI) were prepared by using biological embedding method. SA/B-nZVI was characterized by scanning electron microscope(SEM), Fourier Transform Infrared Spectrometer(FT-IR) and diffraction of X-rays(XRD), and the results showed that nano-zero-valent iron was successfully loaded on corn stover biochar, which inhibited the shortcomings of easy agglomeration. The particle size of nano-zero-valent iron was 27.6 nm and it is evenly embedded in the pellet. SA/B-nZVI can be used to study the adsorption of Pb^(2+), Cu^(2+)and Cd^(2+)in aqueous solution. The maximum adsorption capacities of SA/B-nZVI are 349, 147 and 106 mg/g, respectively, under the optimal adsorption conditions. The theoretical saturated adsorption capacities of SA/B-nZVI for Pb^(2+), Cu^(2+)and Cd^(2+)were calculated by Langmuir equation as 351, 153 and 109 mg/g, respectively. After recycling 5 times, the removal rates of Pb^(2+), Cu^(2+)and Cd^(2+)were 87%, 79% and 73%, respectively.