吸附耦合浮选回收低浓度铅离子

Adsorption coupled with flotation for recovering low concentration of Pb^(2+)

为了高效去除工业废水中的低浓度重金属,开发了一种吸附耦合浮选的工艺,以铅离子(15.0 mg/L)为待去除的重金属,纳米二氧化硅(SNPs)为吸附剂,低浓度的十六烷基三甲基溴化铵(CTAB)作为捕获剂捕获吸附Pb^(2+)的SNPs.实验结果表明,在pH为7.0、SNPs浓度为180.0 mg/L、CTAB加入时间为5 min、CTAB浓度为20.0 mg/L的条件下,铅离子的回收率和富集比分别达到(98.1±1.0)%和12.5±0.6,SNPs的回收率和富集比分别达到(97.2±1.0)%和16.2±0.8,最终残液中Pb^(2+)的浓度为(0.8±0.04)mg/L.在这个过程中,SNPs除了作为吸附剂之外,还可作为新型稳泡剂,显著提高了泡沫的稳定性.此外,Pb^(2+)也易从富集的SNPs上实现进一步分离.

In order to effectively recover low concentration heavy metal ions fronl their industrial wastewater, a promis-ing process of adsorption coupled with flotation ,was developed. Specially, silica nanoparticle （SNP） acted as an adsor-bent to adsorb Pb^2＋ （15.0 mg/L） and cetyl trimethyl ammonium bromide （CTAB） ,was utilized acted as a collector to capture the SNPs. The results showed that under the suitable conditions of pH 7.0, SNP concentration 180.0 mg/L, the adding time of CTAB 5 min, CTAB concentration 20.0 mg/L, the recovel7 percentage and the enrichment ratio of Pb^2＋ reached （98.1± 1.0）% and 12.5 ±0.6, respectively, and the recovery percentage and the enrichment ratio of SNPs reached （97.2± 1.0）% and 16.2±0.8, respectively. Moreover, the concentration of Pb^2＋ in the residual solution ,was （0.8±0.04） mg/L. In this process, SNPs, apart from being an adsorbent, also served as a novel foam stabilizer to enhance the foam stability. Furthermore, Pb^2＋ ,was easily isolated from the enriched SNPs.