Wang Jianchao, Liu Weiqi, Wang Hui, Wang Chongqing, Huang Wenqiu
School of Chemistry and Chemical Engineering, Central South University, Changsha, 410083 Hunan, China.
School of Public Administration, Central South University, Changsha, 410083 Hunan, China.
Waste Manag. 2018 Aug;78:829-840. doi: 10.1016/j.wasman.2018.07.001. Epub 2018 Jul 6.
This work develops a simple and practical process for separation of acrylonitrile-butadienestyrene (ABS) and polystyrene (PS) waste plastics by froth flotation after surface modification using potassium ferrate. ABS plastics containing brominated flame retardants (BFRs) can release hazardous emissions during the process of disposal. Moreover, ABS and PS are typical styrene plastics with similar properties, posing severe restrictions on their separation for recycling. Thus, potassium ferrate modification was investigated and found to decrease selectively the floatability of ABS, providing available process for separation of ABS and PS. Contact angle measurements, FT-IR, XPS and SEM characterization analysis confirmed that potassium ferrate modification can induce the desired changes in the surface properties of ABS. With consideration to separation of ABS and PS, the optimum conditions are potassium ferrate concentration 0.15 M/L, modification time 15 min, temperature 60 °C, stirring rate 200 rpm, frother concentration 14.50 mg/L and flotation time 2 min. Under optimum conditions, separation of ABS and PS with different mixing ratios was accomplished with a recovery and purity of 98.60% and 98.62% respectively. Moreover, reusing of potassium ferrate solution is feasible, further eliminating emissions and cost of this process. Consequently, surface modification using potassium ferrate can be applied for facilitating flotation separation of ABS and PS waste plastics.
本研究开发了一种简单实用的工艺，通过高铁酸钾表面改性后采用泡沫浮选法分离丙烯腈-丁二烯-苯乙烯共聚物（ABS）和聚苯乙烯（PS）废塑料。含溴化阻燃剂（BFRs）的ABS塑料在处置过程中会释放有害排放物。此外，ABS和PS是典型的具有相似性质的苯乙烯类塑料，这对它们的回收分离造成了严重限制。因此，对高铁酸钾改性进行了研究，发现其能选择性降低ABS的可浮性，为ABS和PS的分离提供了可行的工艺。接触角测量、傅里叶变换红外光谱（FT-IR）、X射线光电子能谱（XPS）和扫描电子显微镜（SEM）表征分析证实，高铁酸钾改性可使ABS的表面性质发生预期变化。考虑到ABS和PS的分离，最佳条件为高铁酸钾浓度0.15 M/L、改性时间15分钟、温度60℃、搅拌速率200转/分钟、起泡剂浓度14.50 mg/L和浮选时间2分钟。在最佳条件下，实现了不同混合比例的ABS和PS的分离，回收率和纯度分别为98.60%和98.62%。此外，高铁酸钾溶液的回用是可行的，进一步消除了该工艺的排放物和成本。因此，高铁酸钾表面改性可用于促进ABS和PS废塑料的浮选分离。
