Robustness testing of a free-fall triboelectric separation process for plastic waste recovery

Among the separation techniques used in industries, the triboelectric separation of insulating particles using a rotary tube is an effective way employed in the waste recovery of plastic and mineral products. This process, also called free-fall triboelectric separation, is widely used for the sorting of granular mixtures resulting from industrial plastic wastes. Given that the robustness of such a separation process is an important issue, a standard procedure is used for determining the set point and for minimising the process sensitivity of sorting mixed particles of different polymers to changes in the values of some critical factors. The aim of this paper was to analyse the efficiency of the triboelectric separation process of polymers with respect to any slight variation in the values of the most significant factors. Experiments with a sample of high-density polyethylene and polyvinyl chloride plastic granules were carried out on a laboratory experimental bench. Several one-factor-at-a-time experiments, followed by two factorial designs (one composite and the other fractional), were performed based on the following experimental procedure: (1) determination of the variation limits of the input variables; (2) identification of the set point and (3) robustness testing of the process, i.e. testing whether the performance of the system remains high even when the factors vary slightly around the set point.     

基于摩擦纳米发电机的微塑料实时检测实验研究

采用基于自供电的摩擦纳米发电机(TENG)技术,设计开发了一种利用间断液柱检测水样内微塑料颗粒尺寸和丰度的实时快速检测方法和装置,并通过实验测试完成了对微塑料的尺寸形貌表征和化学元素组成的实时高效检测.研究发现,去离子水中加入微塑料颗粒时,溶液中zeta电位降低,改变了管壁表面的极化电场方向;随着水溶液中微塑料颗粒直径或丰度的增加,开路电压呈现减小趋势,50μm时减小了43.1%,0.250%浓度时减小了79.6%;微塑料颗粒对自来水的开路电压影响显著,以10μm微塑料颗粒为例,开路电压减小了20%,证明了TENG技术对海洋微塑料检测的可行性.     

瓶级聚酯切片静电起电特性试验研究*

为了分析瓶级聚酯切片（PET）生产过程中分析筛处理量对其静电带电特性的影响,基于颗粒振动摩擦带电模拟试验,研究单颗粒PET振动摩擦带电饱和量以及多颗粒PET振动带电荷质比数据。结果表明:瓶级PET产品静电半衰期超过80 ks;PET单颗粒与金属分析筛碰撞摩擦时带电量随振动时间增加趋于饱和,且单粒子荷质比大小可超过16 nC·g-1;随着分析筛内PET总质量增加,PET颗粒间碰撞几率增加,但PET的荷质比值迅速降低。利用工业振动筛处理PET时,应尽量提高总颗粒处理量以控制颗粒带电,抑制静电对粉尘吸附作用,有利于脱除切片中携带的粉尘。     

Electricity nanogenerator from egg shell membrane: A natural waste bioproduct

ABSTRACT

In the era of developing technologies, there is always been a crisis of rising demands of energy. There is no skepticism that a lot of energy is being produced every hour for almost each and every field, but still an exploration is needed to come up with new and viable options for energy creation. The same is the objective of this paper which proposes the use of waste biomaterials in association with organic and inorganic materials as a source of energy to power up small electronic devices. In this research egg shell membrane (ESM)-based triboelectric nanogenerator (TENG) is proposed in combination with calotropis (Calo), cellulose from fruit of Bombax Ceiba (BOM), cellulose in form of tissue paper (TISU), dog hair (DH), polytetrafluoroethylene (PTFE), aluminum (Al), and copper (Cu). ESM is eco-friendly waste food by-product and available in abundance. Characterization of ESM is done by scanning electron microscope (SEM), atomic force microscope (AFM), X-ray diffraction (XRD), and Fourier transform infrared spectrophotometer (FTIR). The proposed ESM-PTFE-based TENG power up 462 green LEDs (462 × 2 V = 924 V ~ 1 kV) without rectifier and produced up to 7.61 µJ energy with 4.7 µF capacitor at 200 tapings. All the proposed ESM-based TENG combinations generate sufficient voltage to turn ON the wrist watch. This green-energy-based TENG has potential application in various fields especially related to medical devices.