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The use of screen-printed electrodes in different monitoring applications, e.g., polluted water, biotechnology, agriculture, industrial process control, and other applications, are continuously being developed. New cheap and open-source potentiostats have been recently emerging, in addition to the commercial and proprietary solutions on the market. In this study, paperbased, screen-printed electrodes were utilised as an alternative solution for ceramic-based electrodes and were tested with two potentiostats (proprietary and low-cost open-source running on wireless 64 bit Linux system installed on Raspberry Pi 3+). Unique paper substrates made from invasive plant papers and one commercial product were used for screen electrode printing. Ink layer thicknesses variations and mechanical grinding were applied, and cyclic voltammetry measurements were conducted. The variation in cyclic voltammetry measurements could be attributed to two sources: the potentiostats showed differences in their sensibility and signal values, and paper surface and structure also contributed to differences. Simultaneously, the additional processing steps, e.g., mechanical grinding, introduced additional measurement variations and differences in the measurement process. [ABSTRACT FROM AUTHOR]

Using disposable screen-printed electrodes is a convenient way of monitoring environmental pollution, production process control etc. Usually, commercially available screen-printed electrodes are used, but more and more studies are being carried out in the field of printing electrodes on thinner, low-cost and versatile substrates, including paper. In the present research, the comparison of screen-printed electrodes printed on different paper-based materials is presented. Two unique and innovative invasive plant-based papers made from (1) Japanese knotweed, (2) Canadian and Giant goldenrod and (3) commercially available cardboard were used as a printing material for the electrodes. The selected paper substrates were characterized, and screen-printed electrodes were printed. The influence of substrates' properties and pre- or post-treatment of the screen-printed electrodes on the electrochemical behaviour is thoroughly analyzed. The results indicate that the printing substrate (roughness) had the most significant influence on the cyclic voltammetry response. Comparing pre- and post-treatment of screen-printed electrodes, it was shown that grinding influenced the electrochemical activity significantly, while corona discharge does not have as significant influence. Besides, it was shown that the invasive plant-based papers are viable alternatives to commercially available papers and can be used as low-cost and eco-friendly alternatives for disposable screen-printed electrodes. [ABSTRACT FROM AUTHOR]

BACKGROUND: Deinking is an important part of paper recycling that involves the removal of ink particles from the paper fibres. This industrial process is important so that the fibres can be recirculated back into paper production, which enables better sustainability as fewer fresh fibres are needed. In this study, we examined five different alternative fibre materials from different agricultural residues and industrial processes for the pilot production of papers. Papers containing fibres from invasive plants (Japanese knotweed), dedicated crops (miscanthus, acacia), agricultural residues (tomato stems), and industrial waste (jute - fibres from coffee bags) were printed with water-based flexo inks and deinked with two separate processes (chemical and enzymes). Mechanical (break and tensile index, breaking length) and optical properties (ISO whiteness, brightness and CIE L*a*b* values) were measured and ink elimination IR700 and deinking efficiency was calculated for the two deinking processes. RESULTS: Enzymatic treatment improved the mechanical properties of deinked pulp in comparison with the classic chemical treatment. Mechanical strength for almost all papers increased slightly (breaking length up to 20% in tomato and jute), and the optical result (brightness) increased similarly for both processes due to the bleaching action of the colour-shaded samples, whereas the deinking efficiency showed mixed results between chemical- and enzyme-type deinking (with chemical achieving better elimination measured at 700 nm) in the typical range of ink elimination values (15-35%) for flexographic inks. This indicates further optimization of the deinking with enzymes is needed due to different alternative fibre compositions and variations of residues in the delignification processes. CONCLUSION: Using a combination of adjusted enzymatic treatment as a precursor for deinking of paper-based packaging materials sourced from alternative fibres showed promising results regarding mechanical properties, whereas the optical properties need to be improved with cellulase optimization or by using mixes of different enzymes. These kinds of paper materials printed with flexo inks were found to be successfully deinkable with the chemical ISO-based deinking protocol. [ABSTRACT FROM AUTHOR]

Sustainability demands circular and material solutions with an emphasis on using local resources. Using alternative fibers from invasive plants and agro-residue promotes local production in smaller paper mills, which have additional benefits for the environment (protecting the local species, reducing agro-industrial waste). In electrophotography printing, toner adhesion is a vital quality parameter showing the prints' resistance against different mechanical stress, leading to toner particle detachment. This study tested six different papers made from invasive plants Japanese Knotweed, Black Locust, Canadian Goldenrod, agro-industrial residues Miscanthus, and Tomato stems and waste jute bags. The papers were printed with electrophotography, and three different toner adhesion methods were used to evaluate the toner adhesion. Paper properties like roughness, surface energy and surface resistivity were tested. The results indicate that uncoated agro-industrial residue and invasive plant papers with low surface roughness, low surface energy and high surface resistivity result in low toner adhesion. The cellulose content of the papers acquired with FTIR analysis did not influence the adhesion. Papers with surface energy over 35 mJ/m2 and surface resistivity below 5E + 1012 Ω values resulted in excellent paper toner adhesion (high IGT printability tester and tape pull test). High grammage and long fibers also improved the adhesion. [ABSTRACT FROM AUTHOR]

Simple, low-cost methods for sensing volatile organic compounds that leave no trace and do not have a detrimental effect on the environment are able to protect communities from the impacts of contaminants in water supplies. This paper reports the development of a portable, autonomous, Internet of Things (IoT) electrochemical sensor for detecting formaldehyde in tap water. The sensor is assembled from electronics, i.e., a custom-designed sensor platform and developed HCHO detection system based on Ni(OH)2–Ni nanowires (NWs) and synthetic-paper-based, screen-printed electrodes (pSPEs). The sensor platform, consisting of the IoT technology, a Wi-Fi communication system, and a miniaturized potentiostat can be easily connected to the Ni(OH)2–Ni NWs and pSPEs via a three-terminal electrode. The custom-made sensor, which has a detection capability of 0.8 µM/24 ppb, was tested for an amperometric determination of the HCHO in deionized (DI) and tap-water-based alkaline electrolytes. This promising concept of an electrochemical IoT sensor that is easy to operate, rapid, and affordable (it is considerably cheaper than any lab-grade potentiostat) could lead to the straightforward detection of HCHO in tap water. [ABSTRACT FROM AUTHOR]