Kinetic and thermodynamic study of gallic acid adsorption on a commercial activated carbon oxidized by ozone

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Evolution of adsorption kinetics and isotherms of gallic acid on an activated carbon oxidized by ozone: Comparison to the raw material

International audienceThe evolutions of both adsorption kinetics and isotherms of gallic acid on a commercial activated carbon(AC), initially submitted to ozone in water for 4 h were studied. The microporous properties wereinvestigated by N2 physisorption at 77 K and the surface oxygen groups created on the surface of thecarbon by oxidation were characterized by Fourier Transform Infrared Spectroscopy (FTIR). The studiesof the adsorption kinetics and the isotherms of gallic acid on the ozonated and non ozonated AC werecarried out at several temperatures (between 5 8C and 50 8C). Four models (pseudo-first order, pseudosecondorder, Elovich and the intraparticle model) were used in order to determine kinetic parameters ofadsorption. The best results were obtained with the pseudo-second order model. Moreover, a decrease inboth the rate constant and the activation energy of adsorption with the ozone exposure time of AC wasevidenced. However, no modification appeared in the adsorption mechanism rate limited by theintraparticle diffusion both for ozonated and for non ozonated AC. Two models (Langmuir and Dubinin–Radushkevich) were tested from experimental isotherms and compared. The Langmuir model providedthe best correlation under all the temperatures. Results showed that ozonation of AC for 4 and 8 h led toan increase in surface oxygen groups, which can be considered as acid groups, without microporousmodification. The adsorption capacity of the oxidized material was increased by a value up to 28% underall the experiments. The Langmuir and the DR models showed that the surface occupied increases andthe process of micropores filling proves to be favoured when the AC is oxidized by ozone

Successful Thrombectomy Improves Functional Outcome in Tandem Occlusions with a Large Ischemic Core

International audienceBackground: Emergent stenting in tandem occlusions and mechanical thrombectomy (MT) of acute ischemic stroke related to large vessel occlusion (LVO-AIS) with a large core are tested independently. We aim to assess the impact of reperfusion with MT in patients with LVO-AIS with a large core and a tandem occlusion and to compare the safety of reperfusion between large core with tandem and nontandem occlusions in current practice. Methods: We analyzed data of all consecutive patients included in the prospective Endovascular Treatment in Ischemic Stroke Registry in France between January 2015 and March 2023 who presented with a pretreatment ASPECTS (Alberta Stroke Program Early CT Score) of 0–5 and angiographically proven tandem occlusion. The primary end point was a favorable outcome defined by a modified Rankin Scale (mRS) score of 0–3 at 90 days. Results: Among 262 included patients with a tandem occlusion and ASPECTS 0–5, 203 patients (77.5%) had a successful reperfusion (modified Thrombolysis in Cerebral Infarction grade 2b-3). Reperfused patients had a favorable shift in the overall mRS score distribution (adjusted odds ratio [aOR], 1.57 [1.22–2.03]; P < 0.001), higher rates of mRS score 0–3 (aOR, 7.03 [2.60–19.01]; P < 0.001) and mRS score 0–2 at 90 days (aOR, 3.85 [1.39–10.68]; P = 0.009) compared with nonreperfused. There was a trend between the occurrence of successful reperfusion and a decreased rate of symptomatic intracranial hemorrhage (aOR, 0.5 [0.22–1.13]; P = 0.096). Similar safety outcomes were observed after large core reperfusion in tandem and nontandem occlusions. Conclusions: Successful reperfusion was associated with a higher rate of favorable outcome in large core LVO-AIS with a tandem occlusion, with a safety profile similar to nontandem occlusion