School of Materials Science and Engineering, Zhengzhou University, Zhengzhou, Henan 450001, China.
School of Materials Science and Engineering, Zhengzhou University, Zhengzhou, Henan 450001, China.
Waste Manag. 2022 Apr 15;143:105-115. doi: 10.1016/j.wasman.2022.02.030. Epub 2022 Feb 28.
Management and safe disposal of chrome-tanned leather wastes generated in leather industry are of great importance due to their potential health risks and environmental hazards. Herein, an integrated strategy was proposed for disposing of chrome-tanned leather scrap (CTLS). This method involves the separation of chromium salts from CTLS with sulfuric acid for recycling purpose, followed by pyrolysis of the acid-treated CTLS in an inert atmosphere. SEM/EDX analysis was employed to characterize the changes in composition and morphology of CTLS after acid treatment. CO and HO are main pyrolysis gases of CTLS, while the acid treatment increases the relative content of aliphatic hydrocarbons and NH in evolved gases. The pyrolysis characteristics and kinetics of the acid-treated CTLS were investigated by thermogravimetric analysis (TGA) at three different heating rates. After 3 and 6 days of acid treatment, the average activation energy of CTLS (450.9 kJ/mol) obtained from the Flynn-Wall-Ozawa method decreased to 369.6 and 351.0 kJ/mol, respectively. It is assumed that the CTLS consists of two pseudocomponents: low-crosslinked collagen (LCol) and highly-crosslinked collagen (HCol). Using the generalized master plots method, random nucleation and nuclei growth model (An model) was found to be the most probable kinetic model for the pyrolysis process of LCol and HCol. The kinetic exponent for pseudocomponent pyrolysis varied between 3.00 and 3.90, and the pre-exponential factor ranged from 5.83 × 10 to 2.93 × 10 min. The results of the present study provide an alternative route and useful information for recycling and disposing of chrome-containing leather wastes.
由于铬鞣皮革废弃物具有潜在的健康风险和环境危害，因此对其进行妥善管理和安全处置至关重要。本文提出了一种综合策略来处理铬鞣革废料（CTLS）。该方法涉及用硫酸从 CTLS 中分离铬盐以进行回收，然后在惰性气氛中对酸处理后的 CTLS 进行热解。通过 SEM/EDX 分析对酸处理前后 CTLS 的组成和形貌变化进行了表征。CO 和 HO 是 CTLS 的主要热解气体，而酸处理会增加挥发气体中脂肪族烃和 NH 的相对含量。通过热重分析（TGA）在三种不同的加热速率下研究了酸处理 CTLS 的热解特性和动力学。经过 3 天和 6 天的酸处理后， Flynn-Wall-Ozawa 法得到的 CTLS 的平均活化能（450.9 kJ/mol）分别降低至 369.6 和 351.0 kJ/mol。假设 CTLS 由两种拟组分组成：低交联胶原（LCol）和高交联胶原（HCol）。使用广义主图法，发现随机成核和核生长模型（An 模型）最有可能是 LCol 和 HCol 热解过程的动力学模型。拟组分热解的动力学指数在 3.00 到 3.90 之间变化，而前指数因子在 5.83×10 到 2.93×10 min 之间变化。本研究的结果为回收和处理含铬皮革废物提供了一种替代途径和有用的信息。
