Role of Inherent Inorganic Constituents in SO₂ Sorption Ability of Biochars Derived from Three Biomass Wastes

Biochar is rich in both organic carbon and inorganic components. Extensive work has attributed the high sorption ability of biochar to the pore structure and surface chemical property related to its organic carbon fraction. In this study, three biochars derived from dairy manure (DM-biochar), sewage sludge (SS-biochar), and rice husk (RH-biochar), respectively, were evaluated for their SO₂ sorption behavior and the underlying mechanisms, especially the role of inherent inorganic constituents. The sorption capacities of SO₂ by the three biochars were 8.87–15.9 mg g^–1. With the moisture content increasing from 0% to 50%, the sorption capacities increased by up to about 3 times, mainly due to the formation of alkaline water membrane on the biochar surface which could promote the sorption and transformation of acidic SO₂. DM- and SS-biochar containing larger mineral constituents showed higher sorption capacity for SO₂ than RH-biochar containing less mineral components. CaCO₃ and Ca₃(PO₄)₂ in DM-biochar induced sorbed SO₂ transformation into K₂Ca­(SO₄)₂·H₂O and CaSO₄·2H₂O, while the sorbed SO₂ was converted to Fe₂(SO₄)₃·H₂SO₄·2H₂O, CaSO₄·2H₂O, and Ca₃(SO₃)₂SO₄·12H₂O in SS-biochar. For RH-biochar, K₃H­(SO₄)₂ might exist in the exhausted samples. Overall, the chemical transformation of SO₂ induced by biochar inherent mineral components occupied 44.6%–85.5% of the total SO₂ sorption. The results obtained from this study demonstrated that biochar as a unique carbonaceous material could distinctly be a promising sorbent for acidic SO₂ removal in which the inorganic components played an important role in the SO₂ sorption and transformation

The Interfacial Behavior between Biochar and Soil Minerals and Its Effect on Biochar Stability

In this study, FeCl₃, AlCl₃, CaCl₂, and kaolinite were selected as model soil minerals and incubated with walnut shell derived biochar for 3 months and the incubated biochar was then separated for the investigation of biochar-mineral interfacial behavior using XRD and SEM-EDS. The XPS, TGA, and H₂O₂ oxidation were applied to evaluate effects of the interaction on the stability of biochar. Fe₈O₈(OH)₈Cl_1.35 and AlCl₃·6H₂O were newly formed on the biochar surface or inside of the biochar pores. At the biochar-mineral interface, organometallic complexes such as Fe–O–C were generated. All the 4 minerals enhanced the oxidation resistance of biochar surface by decreasing the relative contents of C–O, CO, and COOH from 36.3% to 16.6–26.5%. Oxidation resistance of entire biochar particles was greatly increased with C losses in H₂O₂ oxidation decreasing by 13.4–79.6%, and the C recalcitrance index (<i>R</i>₅₀,_bicohar) in TGA analysis increasing from 44.6% to 45.9–49.6%. Enhanced oxidation resistance of biochar surface was likely due to the physical isolation from newly formed minerals, while organometallic complex formation was probably responsible for the increase in oxidation resistance of entire biochar particles. Results indicated that mineral-rich soils seemed to be a beneficial environment for biochar since soil minerals could increase biochar stability, which displays an important environmental significance of biochar for long-term carbon sequestration

Kaolinite Enhances the Stability of the Dissolvable and Undissolvable Fractions of Biochar via Different Mechanisms

Input of biomass-derived biochar into soil is recognized as a promising method of carbon sequestration. The long-term sequestration effect of biochar depends on the stability of both its dissolvable and undissolvable fractions in soil, which could be affected by their interactions with soil minerals. Here, walnut shell-derived biochar was divided into dissolvable and undissolvable fractions and then interacted with kaolinite. Stability of kaolinite-biochar associations was evaluated by chemical oxidation and biological degradation. At low dissolvable biochar concentrations, the association was mainly attributed to “Ca²⁺ bridging” and “ligand exchange”, whereas “van der Waals attraction” was dominant at high concentrations. For the undissolvable biochar, kaolinite raised the activation energy of its surface by 22.1%, causing a reduction in biochar reactivity. By chemical oxidation, kaolinite reduced the C loss of total biochar by 42.5%, 33.1% resulting from undissolvable biochar and 9.4% from dissolvable biochar. Because of the presence of kaolinite, the loss of biodegradable C in total biochar was reduced by 49.4% and 48.2% from undissolvable fraction and 1.2% from dissolvable fraction. This study indicates that kaolinite can increase the stability of both dissolvable and undissolvable biochar, suggesting that kaolinite-rich soils could be a beneficial environment for biochar for long-term carbon sequestration

Genotypic and allelic associations of <i>GAPDH</i> variants with PD.

<p>^a Adjusted by Bonferroni correction for multiple testing.</p><p>Genotypic and allelic associations of <i>GAPDH</i> variants with PD.</p

Basic characteristics of study subjects.

<p>Basic characteristics of study subjects.</p

Intensive Ambulance-Delivered Blood-Pressure Reduction in Hyperacute Stroke

BackgroundTreatment of acute stroke, before a distinction can be made between ischemic and hemorrhagic types, is challenging. Whether very early blood-pressure control in the ambulance improves outcomes among patients with undifferentiated acute stroke is uncertain.MethodsWe randomly assigned patients with suspected acute stroke that caused a motor deficit and with elevated systolic blood pressure (≥150 mm Hg), who were assessed in the ambulance within 2 hours after the onset of symptoms, to receive immediate treatment to lower the systolic blood pressure (target range, 130 to 140 mm Hg) (intervention group) or usual blood-pressure management (usual-care group). The primary efficacy outcome was functional status as assessed by the score on the modified Rankin scale (range, 0 [no symptoms] to 6 [death]) at 90 days after randomization. The primary safety outcome was any serious adverse event.ResultsA total of 2404 patients (mean age, 70 years) in China underwent randomization and provided consent for the trial: 1205 in the intervention group and 1199 in the usual-care group. The median time between symptom onset and randomization was 61 minutes (interquartile range, 41 to 93), and the mean blood pressure at randomization was 178/98 mm Hg. Stroke was subsequently confirmed by imaging in 2240 patients, of whom 1041 (46.5%) had a hemorrhagic stroke. At the time of patients' arrival at the hospital, the mean systolic blood pressure in the intervention group was 158 mm Hg, as compared with 170 mm Hg in the usual-care group. Overall, there was no difference in functional outcome between the two groups (common odds ratio, 1.00; 95% confidence interval [CI], 0.87 to 1.15), and the incidence of serious adverse events was similar in the two groups. Prehospital reduction of blood pressure was associated with a decrease in the odds of a poor functional outcome among patients with hemorrhagic stroke (common odds ratio, 0.75; 95% CI, 0.60 to 0.92) but an increase among patients with cerebral ischemia (common odds ratio, 1.30; 95% CI, 1.06 to 1.60).ConclusionsIn this trial, prehospital blood-pressure reduction did not improve functional outcomes in a cohort of patients with undifferentiated acute stroke, of whom 46.5% subsequently received a diagnosis of hemorrhagic stroke. (Funded by the National Health and Medical Research Council of Australia and others; INTERACT4 ClinicalTrials.gov number, NCT03790800; Chinese Trial Registry number, ChiCTR1900020534.)