methyl orange
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Polymers ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 332
Qiang Li ◽  
Xianhui An ◽  
Xueren Qian

Cellulose fiber (CelF) is a biodegradable and renewable material with excellent performance but negligible triboelectric polarizability. Methods to enhance and rationally tune the triboelectric properties of CelF are needed to further its application for energy harvesting. In this work, methyl-orange-doped polypyrrole (MO-PPy) was in situ coated on CelF as a mediating layer to promote the growth of metal–organic framework ZIF-8 and to construct a cellulose-based triboelectric nanogenerator (TENG). The results showed that a small amount of MO-PPy generated in situ significantly promoted the growth of ZIF-8 on CelF, and the ZIF-8 deposition ratio was able to increase from 7.8% (ZIF-8/CelF) to 31.8% (ZIF-8/MO-PPy@CelF). ZIF-8/MO-PPy@CelF remained electrically conductive and became triboelectrically positive, and the triboelectricity’s positivity was improved with the increase in the ZIF-8 deposition ratio. The cellulose-based TENG constructed with ZIF-8/MO-PPy@CelF (31.8% ZIF-8 deposition ratio) and polytetrafluoroethylene (PTFE) could generate a transfer charge of 47.4 nC, open-circuit voltage of 129 V and short-circuit current of 6.8 μA—about 4 times higher than those of ZIF-8/CelF (7.8% ZIF-8 deposition ratio)—and had excellent cycling stability (open-circuit voltage remained almost constant after 10,000 cycles). MO-PPy not only greatly facilitated the growth of ZIF-8 on CelF, but also acted as an electrode active phase for TENG. The novel TENG based on ZIF-8/MO-PPy@CelF composite has cheerful prospects in many applications, such as self-powered supercapacitors, sensors and monitors, smart pianos, ping-pong tables, floor mats, etc.

2022 ◽  
Vol 9 ◽  
Shuai Zhang ◽  
Huixue Ren ◽  
Kaifang Fu ◽  
Wenqing Cheng ◽  
Daoji Wu ◽  

The printing and dyeing wastewater produced by different dyes, as well as different printing and dyeing processes, have different components. These wastewater have high toxicity, high organic concentration, and deep chromaticity. Ozone catalytic oxidation is a very promising technical method for wastewater treatment. In this paper, Mn/Mg/Ce ternary catalyst was prepared, and the ozone catalytic oxidation treatment of actual and simulated printing and dyeing wastewater was performed to study the performance of four different carrier catalysts, namely, molecular sieve (MS), silica gel (SG), attapulgite (ATP), and nano alumina (Al2O3), by simulated dynamic test. The effects of reaction time, pH, and catalyst dosage on methyl orange degradation were studied. The results showed that under the optimum treatment conditions (120 min, pH 11, and 12.5 g/L catalyst dosage), the degradation rate of methyl orange reached 96% and the removal rate of the chemical oxygen demand of printing and dyeing wastewater reached 48.7%. This study shows that the treatment effect of ozone catalytic oxidation on printing and dyeing wastewater is remarkably improved after catalyst addition. This study provides a new choice of ozone catalyst for the degradation of printing and dyeing wastewaters in the future.

Muhammad Irfan Jahanger ◽  
Naveed Akhtar Shad ◽  
Muhammad Munir Sajid ◽  
Kanwal Akhtar ◽  
Yasir Javed ◽  

2022 ◽  
Vol 2022 ◽  
pp. 1-15
Temesgen Abeto Amibo ◽  
Surafel Mustefa Beyan ◽  
Tsegaye Markos Damite

The brown teff straw was utilized in this study to produce silica using the sol-gel technique. After pretreatment, the raw material of brown teff straw was characterized. The data were analyzed using the central composite design and response surface technique, and four independent parameters, namely, temperature, NaOH concentration, rotational speed, and extraction time, were evaluated for process optimization. Before extracting silica with an alkaline solution, the silica content in the ash was determined using an AAS spectrometer. The silica content of teff straw ash is around 92.89%. The ash was treated with NaOH solution in the concentrations range of 1 M to 3 M (0.5 M interval). The extraction time varied at intervals of 55, 70, 85, 100, and 115 minutes. Temperatures were changed using magnetic stirrer equipment in the range of 80°C to 100°C (5°C interval). At 350 rpm, 400 rpm, 450 rpm, 500 rpm, and 550 rpm, the rotating speed was adjusted. The best extraction conditions for amorphous silica were 1.50 M NaOH, 109.99 min, 94.98°C, and a rotating speed of 499.57 rpm, with a maximum yield of 85.85%. XRD and FTIR analyses were used to assess the physicochemical characteristics of the extracted silica. The aqueous solutions of methyl orange were used to test the adsorption efficiency of silica. The percent of removal efficiency for methyl orange was 90.48%.

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