Compare the Levels of Use of Activated Carbons for Water Treatment and Biogas Purification as Well as Their Reactive Abilities

The conducted research concerned a comparison of the levels of use of activated carbons purifying water and biogas, and their reactivation capacity. The process of reactivation of both activated carbons was carried out using laboratory kiln. Reactivation was carried out in identical conditions for both tested samples. The obtained results proved that both activated carbons can be regenerated although they differ significantly in degree of use. It was proven that the technological process, the degree of contamination, and the contact time of activated carbon with the medium have a significant impact on the quality, speed, and success of the reactivation process.

Molecular Modeling Studies on the Multistep Reactivation Process of Organophosphate-Inhibited Acetylcholinesterase and Butyrylcholinesterase

Poisoning with organophosphorus compounds used as pesticides or misused as chemical weapons remains a serious threat to human health and life. Their toxic effects result from irreversible blockade of the enzymes acetylcholinesterase and butyrylcholinesterase, which causes overstimulation of the cholinergic system and often leads to serious injury or death. Treatment of organophosphorus poisoning involves, among other strategies, the administration of oxime compounds. Oximes reactivate cholinesterases by breaking the covalent bond between the serine residue from the enzyme active site and the phosphorus atom of the organophosphorus compound. Although the general mechanism of reactivation has been known for years, the exact molecular aspects determining the efficiency and selectivity of individual oximes are still not clear. This hinders the development of new active compounds. In our research, using relatively simple and widely available molecular docking methods, we investigated the reactivation of acetyl- and butyrylcholinesterase blocked by sarin and tabun. For the selected oximes, their binding modes at each step of the reactivation process were identified. Amino acids essential for effective reactivation and those responsible for the selectivity of individual oximes against inhibited acetyl- and butyrylcholinesterase were identified. This research broadens the knowledge about cholinesterase reactivation and demonstrates the usefulness of molecular docking in the study of this process. The presented observations and methods can be used in the future to support the search for new effective reactivators.

Electrocatalytic dimeric inactivation mechanism by a porphyrinic molecular-type catalyst: integration in a glucose/O2 fuel cell

We report a chemical inactivation/redox reactivation process (IAP) based on the surface-confined rhodium–porphyrinic catalyst on a multi-walled carbon nanotube surface which presents an excellent and stable electron transfer.

Simulation of the Reactivation of Partially Inactivated Biocatalysts in Sequential Batch Reactors

The enzymatic reactivation process enables the recovery of catalytic activity for inactive biocatalysts. However, its effect on the specific productivity of the processes has not been studied. The main objective of this work was to evaluate the specific productivity of the processes with and without reactivation using the program Spyder Python (3.7). Using fixed values for all of the parameters, the global specific productivity was 8 mM/h·gbiocat for the process without reactivation, and 4 mM/h·gbiocat for the process with reactivation. Random numbers were generated to use as different values for parameters, and the results yielded a global specific productivity of 3.79 mM/h·gbiocat for the process with reactivation and 3.68 mM/h·gbiocat for the process without reactivation. ANOVA tests showed that there were significant differences between the specific global productivities of the two processes. Reactivation has great potential for use when the biocatalyst is of high cost.

Understand the interaction modes and reactivity of trimedoxime toward MmAChE inhibited by nerve agents: theoretical and experimental Aspects

The organophosphorus compounds (OP) are used as both chemical weapons and pesticides. However, these agents are very dangerous and toxic to humans, animals, and the environment. Thus, investigations with reactivators have been deeply developed in order to design new antidotes with better efficiency, as well as greater spectrum of action in the AChE reactivation process. With that in mind, in this work, we investigated the behavior of trimedoxime toward the Mus musculus Acetylcholinesterase (MmAChE) inhibited by a range of nerve agents, such as chemical weapons. From experimental essays, reactivation percentages were obtained for the reactivation of different AChE-OP complexes. On the other hand, theoretical calculations were performed to assess the differences of interaction modes and reactivity of trimedoxime within AChE active site. Comparing theoretical and experimental data, it is possible to notice that the oxime, in most case, showed better reactivation percentages at higher concentrations, with the best result for the reactivation of the AChE-VX adduct. From this work, it was revealed that the mechanistic process contributes most to the oxime efficiency than the interaction in the site. In this way, this study was important to better understand the reactivation process through trimedoxime, contributing to the proposal of novel antidotes.

Understanding the Interaction Modes and Reactivity of Trimedoxime toward MmAChE Inhibited by Nerve Agents: Theoretical and Experimental Aspects

Organophosphorus (OP) compounds are used as both chemical weapons and pesticides. However, these agents are very dangerous and toxic to humans, animals, and the environment. Thus, investigations with reactivators have been deeply developed in order to design new antidotes with better efficiency, as well as a greater spectrum of action in the acetylcholinesterase (AChE) reactivation process. With that in mind, in this work, we investigated the behavior of trimedoxime toward the Mus musculus acetylcholinesterase (MmAChE) inhibited by a range of nerve agents, such as chemical weapons. From experimental assays, reactivation percentages were obtained for the reactivation of different AChE–OP complexes. On the other hand, theoretical calculations were performed to assess the differences in interaction modes and the reactivity of trimedoxime within the AChE active site. Comparing theoretical and experimental data, it is possible to notice that the oxime, in most cases, showed better reactivation percentages at higher concentrations, with the best result for the reactivation of the AChE–VX adduct. From this work, it was revealed that the mechanistic process contributes most to the oxime efficiency than the interaction in the site. In this way, this study is important to better understand the reactivation process through trimedoxime, contributing to the proposal of novel antidotes.

Friends or strangers? Attempts at reactivating buyer–supplier relationships

Purpose The purpose of this paper is to explore an important management aspect of business relationship dynamics, namely, the reactivation process of previously ended buyer–supplier relationships. Design/methodology/approach A processual case study approach focusing on a single in-depth case has been used. The case is based on longitudinal data from a number of sources concerning one reactivation failure. Findings Grounded in previous research and based on this study’s case findings, the authors have designed a model of analysis for relationship reactivation processes. Using the model on this study’s particular case, the authors show how the structural properties of network embeddedness and resource ties worked in favor of the process, whereas the social bonds and the lack of them led to mistrust that disturbed the negotiation and, hence, worked against the reactivation process. Originality/value This study makes a contribution to the field of relationship dynamics by exploring relationship reactivation processes. The designed model shows how reactivation can be understood as an interplay between structural properties and (re)building activities and contributes new knowledge on factors that affect this process.

Reactivation Process of Activated Carbons: Effect on the Mechanical and Adsorptive Properties

Carbon reactivation is a strategy to reduce waste and cost in many industrial processes, for example, effluent treatment, food industry, and hydrometallurgy. In this work, the effect of physical and chemical reactivation of granular activated carbon (AC) was studied. Spent activated carbon (SAC) was obtained from a carbon in pulp (CIP) leaching process for gold extraction. Chemical and physical reactivations were evaluated using several acid-wash procedures (HCl, HNO3, H2SO4) and thermal treatment (650–950 °C) methods, respectively. The effect of the reactivation processes on the mechanical properties was evaluated determining ball pan hardness and normal abrasion in pulp resistance. The effect on the adsorptive properties was evaluated via the iodine number, the gold adsorption value (k expressed in mg Au/g AC), and Brunauer–Emmett–Teller (BET) surface area. Initial characterization of the SAC showed an iodine number of 734 mg I2/g AC, a k value of 1.37 mg Au/g AC, and a BET surface area of 869 m2/g. The best reactivation results of the SAC were achieved via acid washing with HNO3 at 20% v/v and 50 °C over 30 min, and a subsequent thermal reactivation at 850 °C over 1 h. The final reactivated carbon had an iodine number of 1199 mg I2/g AC, a k value of 14.9 mg Au/g AC, and a BET surface area of 1079 m²/g. Acid wash prior to thermal treatment was critical to reactivate the SAC. The reactivation process had a minor impact (<1% change) on the mechanical properties of the AC.