The aim of this work is developing an adsorbent for the removal of anionic Acid Blue 45 dye from aqueous solutions. In this regard, the polyaniline/sulfonated-covalent organic polymer nanocomposites (PANI/S-COP NCs) were synthesized by in situ chemical polymerization method. The structure and morphology of these prepared nanocomposites were characterized by different techniques. The structural stability of the synthesized adsorbent was examined under different pH conditions. To optimize the adsorption conditions, various parameters such as pH, dye concentration, adsorbent dosage, contact time, and temperature were investigated. The maximum adsorption capacity of the prepared composite for 100 ppm of dye (at 25.0 C, pH: 5, and time: 120 minutes as optimum conditions) was 117 mg g −1. Different adsorption models were applied for the fitting of the obtained experimental data. It was found that the adsorption data can be well fitted to the linear Langmuir model (R 2 : .999). The adsorption kinetics can also be well described by the linear pseudosecond-order model, indicating the chemical adsorption mechanism for the dye molecules on the PANI/S-COP NCs surface.

Abstract

A flexible piezoelectric composite, made from Lead Zirconate Titanate(PZT) powder and Unsaturated polyester (UPE) resin, was doped with small amount of carbon semiconductor powder. The piezoelectric strain coefficient (d 33 ) and the dielectric behavior have been studied for this ceramic/polymer composite. The dielectric constant processes of the composite were observed to be dominated by those of undoped ceramic-polymer. The practical results of PZT/UPE/C with ratio 49/50/1 adding a semiconductor phase in the composite showed piezoelectric strain coefficient can be controlled and a continuous electric flux path could be created between the PZT grains. This composite may be poled at low voltage and in shorter time compared with composites without a conductive phase.

In the fabrication of paper, a slurry with cellulose fibers and other matter is drained, pressed, and dried. The latter step requires considerable energy consumption. In the structure of wet paper, there are two differ-ent types of water: free water and bound water. Free water can be removed most effectively. However, removing bound water consumes a large portion of energy during the process. The focus of this paper is on the intermediate stage of the drying process, from free water toward bound water where the remaining free water is present on the surfaces of the fibers in the form of a liquid film. For simplicity, the drying process considered in this study corresponds to pure convective drying through the paper sheet. The physics of removing a thin liquid film trapped between fibers in the paper drying process is explored. The film is assumed to be incompressible, viscous, and subject to evaporation, thermocapillarity, and surface tension. By using a volume of fluid (VOF) model, the effect of the previously mentioned parameters on drying behavior of the thin film is investigated.

The paper drying process is very energy inefficient. More than two-thirds of the total energy used in a paper machine is for drying paper. Novel drying technologies, such as ultrasound (US) drying, can be assessed numerically for developing next-generation drying technologies for the paper industry. This work numerically illustrates the impact on drying process energy efficiency of US transducers installed on a two-tiered dryer section of a paper machine. Piezoelectric transducers generate ultrasound waves, and liquid water mist can be ejected from the porous media. The drying rate of handsheet paper in the presence of direct-contact US is measured experimentally, and the resultant correlation is included in the theoretical model. The drying section of a paper machine is simulated by a theoretical drying model. In the model, three scenarios are considered. In the first scenario, the US modules are positioned in the dryer pockets, while in the second scenario, they are placed upstream of the drying section right after the press section. The third case is the combination of the first and second scenarios. The average moisture content and temperature during drying, enhancement of total mass flux leaving the paper by the US mechanism, total energy consumption, and thermal effect of heated US transducers are analyzed for all cases. Results show that the application of the US can decrease the total number of dryer drums for drying paper. This numerical study is based on the US correlation obtained with the US transducer in direct contact with the paper sample. Thus, future work should include US correlation based on a non-contact US transducer.