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In vitro studies
Published in Ze Zhang, Mahmoud Rouabhia, Simon E. Moulton, Conductive Polymers, 2018
A. Lee Miller, Huan Wang, Michael J. Yaszemski, Lichun Lu
It is possible to utilize the conductive capacity of PPy while minimizing PPy’s disadvantages. This can be accomplished by using a copolymer; numerous copolymers have been developed using various polymers to add processability and better mechanical properties. PCLF has successfully been used (Runge et al. 2010; Moroder et al. 2011) to create electrically conductive polymer nanocomposites of PCLF-PPy capable of supporting both PC12 cells and dorsal root ganglia neurite extension (Runge et al. 2010). Dopants, including naphthalene-2-sulfonic acid (NSA) sodium salt and dodecylbenzenesulfonic acid (DBSA) sodium salt, have been shown to support cell attachment, proliferation, and neurite extension (Runge et al. 2010). Having such promising material properties, several studies involving electrical stimulation were conducted. One notable finding from these studies is the ability to form nerve conduits. PCLF-PPy materials have increased flexibility compared with normal PPy, while still maintaining good mechanical strength (Moroder et al. 2011). Additionally, it was shown that neurites can grow parallel to the applied current, leading to the ability to direct the extension of the neurites (Moroder et al. 2011).
Chemistries and Biodegradability of Conducting Polymers
Published in Ram K. Gupta, Conducting Polymers, 2022
Shi and coworkers reported conductive and biodegradable composites consisting of oxidized polypyrrole nanoparticles and poly(d,l-lactide) (PDLLA) using emulsion polymerization in the presence of FeCl3 (Figure 4.7a) [34]. The Ppy nanoparticles aggregated in a matrix of PDLLA to form the conductive network. The resultant Ppy/PDLLA membrane obtains a surface resistivity of 1 × 103 Ω/square with 3% Ppy loading. Authors have demonstrated the stability by performing a biologically meaningful electrical conductivity (100 mV) on the membrane in the environment of cell culture for 1000 h. Additionally, the fibroblasts seeded on the copolymers were upregulated under the stimulation DC, indicating the potential for tissue engineering applications (Figure 4.7b). Runge and coworkers reported a kind of biodegradable composites made from the polymerization of pyrrole in preformed PCLF scaffolds (PCLF-Ppy) [35]. As shown in Figure 4.7c and d, PCLF-Ppy was synthesized under different conditions with various anions, e.g., naphthalene-2-sulfonic acid sodium salt (NSA), dodecylbenzene sulfonic acid sodium salt (DBSA), dioctyl sulfosuccinate sodium salt (DOSS), and lysine to study the impact of composition on conductivity and cellular compatibility. The PCLF-Ppy showed a conductivity of 6 mS/cm with 13.5% polypyrrole. In vitro cell test results indicated that PCLF-Ppy prepared with DBSA or NSA could support the attachment and proliferation of the DRG and PC12 cells. Due to the mild polymerization conditions, the Ppy was widely used to endow the biopolymers’ conductivity by surface modification technology without damaging their intrinsic morphologies and structures. For instance, an in situ oxidative polymerization of Ppy was performed to modified silk fabrics using FeCl3 as a catalyst in the aqueous solutions [36]. The polymerization did not affect the molecular conformation and the intrinsic crystal structure of the silks, but with the improved thermal stability and electrical characteristics. As shown in Figure 4.7e–g, Lee and coworkers reported biodegradable conducting scaffolds prepared by electrospinning poly(lactic-co-glycolic acid) (PLGA) and subsequently polymerizing conducting monomers in situ [37]. Compared with the uncoated PLGA control samples, Ppy in the scaffolds promoted the proliferation and differentiation of PC12 cells.
Treatment of Leather Plant Effluents
Published in Mihir Kumar Purkait, Piyal Mondal, Chang-Tang Chang, Treatment of Industrial Effluents, 2019
Mihir Kumar Purkait, Piyal Mondal, Chang-Tang Chang
Sequencing batch reactor (SBR) proved to be beneficial due to the presence and enrichment of particular microbial species, which are capable of carrying out biological processes like nitrification and denitrification. The performance of SBR at a temperature range of 7°C–30°C was studied for the removal of nitrogen in tannery wastewater. Nitrification and denitrification were maintained by adjusting the sludge age for each temperature range. Due to its flexible operation technique, many researchers described it as a reliable treatment technique for tannery wastewater application. Song et al. (2004) studied the biodegradation of naphthalene-2-sulfonic acid, the main component of the naphthalene sulfonate, by Arthrobacter sp. 2AC and Comamonas sp. 4BC (AC and BC denotes specific DNA sequencing pattern). These two bacterial strains were isolated from tannery-activated sludge after the study. The study described the degradation of all components of the condensation product of 2-naphthalene sulfonic acid and formaldehyde (CNSF) by fungus Cunninghamella polymorpha. They suggested a combination of C. polymorpha and Arthrobacter sp. (2AC) or Comamonas sp. (4BC) for the treatment of tannery wastewater. Conventional cultures could not treat saline wastewaters of values higher than 3%–5% (w/v) and shifts in salt concentration, causing significant failures in system performance. Senthilkumar et al. (2008) studied the biodegradation of tannery soak liquor by employing Pseudomonas aeruginosa, Bacillus flexus, Exiguobacterium homiense, and Staphylococcus aureus isolated from soak liquor, marine soil, salt lake saline liquor, and seawater, respectively. The COD removal achieved was appreciably around 80% at 8% (w/v) salinity, but with an increase in salt concentration to 10% (w/v), a decrease in COD removal efficiency was observed. Nitrification process is inhibited due to the presence of sulfide, chromium, chloride, and fluctuation in temperature. Organic carbon and nitrogen removal variation with temperature variation was studied for a full-scale industrial-activated sludge plant treating leather tanning wastewaters. A minor impact of temperature change was observed on COD removal efficiency (4%–5%), while it tremendously affected total nitrogen removal. Investigation on the performance of intermittent aeration type of operation was carried out by many researchers with a temperature fluctuation between 21°C and 35°C. The nitrification performance was found to improve with an increase in aeration intensity, and the total nitrogen removal increased to 60% with the application of intermittent aeration.
Structural insights into the extraction mechanism of cobalt(II) with dinonylnaphthalene sulfonic acid and 2-ethylhexyl 4-pyridinecarboxylate ester
Published in Journal of Coordination Chemistry, 2018
Shan Zhu, Huiping Hu, Jiugang Hu, Jiyuan Li, Fang Hu, Yongxi Wang
Dinonyl naphthalene sulfonic acid (HDNNS) (50% purity) was purchased from Shanghai Jia Chen Chemical Co., Ltd., purified and characterized as described elsewhere [39]. Naphthalene-2-sulfonic acid (HNS) (98% purity), an analog of HDNNS, was purchased from Adamas Reagent Co. Ltd. and dried under vacuum for 12 h at 50 °C prior to use. 2-Ethylhexyl 4-pyridinecarboxylate ester (L) was synthesized following the procedure described elsewhere [42] except for altering zinc oxide catalyst into solid super acidic catalyst in this reaction. The final purity was verified by FT-IR and 1H-NMR, respectively. Methyl isonicotinate (LI) (99% purity), was purchased from Shanghai Macklin Biochemical Co., Ltd. and used without further purification. Cobalt sulfate heptahydrate (98.5% purity) used to prepare cobalt sulfate stock solution was purchased from Sinopharm Chemical Reagent Co., Ltd. Other chemicals were of analytical grade. The structures of the two types of 4-pyridinecarboxylate esters are shown in Figure 1.