School of Chemical Engineering, University of Campinas (UNICAMP), Cidade Universitária Zeferino Vaz, Campinas, São Paulo, 13083-852, Brazil.
Environ Sci Pollut Res Int. 2019 Oct;26(28):28455-28469. doi: 10.1007/s11356-018-3378-z. Epub 2018 Oct 6.
In this study, two novel low water-soluble sericin and alginate-based biosorbents were successfully developed for precious metal removal from wastewater: sericin and alginate particles chemically crosslinked by proantocyanidins (SAPAs) and sericin, alginate and polyvinyl alcohol particles (SAPVA). The proportions of proantocynidins (PAs) or polyvinyl alcohol (PVA) added to sericin (2.5% w/v) and alginate (2.0% w/v) blend were 0.5, 1.5, 2.5 and 3.5% w/v. Among these concentrations, particles produced with 0.5% w/v of PVA or 2.5% w/v of PAs presented the lowest water solubility percentages (3.74 ± 0.05 and 3.56 ± 0.21%, respectively) and the following metallic affinity order: AuCl > PdCl > PtCl > Ag. Then, gold biosorption kinetics by SAPAs was evaluated at three gold initial concentrations (72.88, 187.12, and 273.79 mg/L), and its performance was compared to activated carbon adsorbent uptake. The data modeling revealed that the process follows pseudo-first-order kinetics and is mainly controlled by external diffusion. SAPAs before and after gold biosorption (SAPAs-gold) were characterized by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy, optical microscopy, helium pycnometry, mercury porosimetry, N physisorption, and Fourier-transform infrared spectroscopy.
在这项研究中，成功开发了两种新型低水溶性丝胶和海藻酸盐基生物吸附剂，用于从废水中去除贵金属：丝胶和海藻酸盐颗粒通过原花青素（SAPAs）和丝胶、海藻酸盐和聚乙烯醇颗粒（SAPVA）化学交联。添加到丝胶（2.5%w/v）和海藻酸盐（2.0%w/v）混合物中的原花青素（PAs）或聚乙烯醇（PVA）的比例为 0.5、1.5、2.5 和 3.5%w/v。在这些浓度中，用 0.5%w/v 的 PVA 或 2.5%w/v 的 PAs 制成的颗粒具有最低的水溶性百分比（分别为 3.74±0.05%和 3.56±0.21%），以及以下金属亲和顺序：AuCl> PdCl> PtCl> Ag。然后，在三个初始金浓度（72.88、187.12 和 273.79mg/L）下评估 SAPAs 对金的吸附动力学，并将其性能与活性炭吸附剂的吸附进行比较。数据建模表明，该过程遵循准一级动力学，主要受外部扩散控制。用扫描电子显微镜结合能谱仪、光学显微镜、氦比重计、压汞仪、N 物理吸附和傅里叶变换红外光谱对吸附金前后的 SAPAs（SAPAs-gold）进行了表征。
