Stable emulsified oil droplets are difficult to separate because of persistent interfacial films and colloidal stability. Garlic-extract-functionalized Fe₃O₄ magnetic colloids, operationally denoted Allicin@Fe₃O₄, were prepared by in situ coprecipitation as organic–inorganic building blocks for gel-like interfacial capture. The sample name identifies the allicin-containing garlic-extract route and does not imply that allicin was proven to be the predominant surface species. SEM, FTIR, and XRD supported deposition of an organic, sulfur/oxygen-containing surface layer and retention of crystalline Fe₃O₄, but these methods are not species-specific. The colloids removed more than 95% of emulsified oil within 20 min and reached an experimental equilibrium apparent uptake of approximately 380 mg·g⁻¹. Tests across pH 3–11, 0–50 g·L⁻¹ NaCl, 15–55 °C, and representative coexisting ions showed robust but condition-dependent removal. Removal remained above 90% after five reuse cycles and was approximately 84% after ten cycles. Calculations using allicin as a representative garlic organosulfur molecule suggest how polar sulfur/oxygen regions and allyl segments could favor oil–droplet anchoring and association; they do not establish the surface composition of the extract-derived coating. The capture behavior is consistent with transient, gel-like particle–droplet association coupled to magnetic recovery. These results connect bio-derived surface functionalization, gel-related colloidal structuring, and magnetic separation under the tested batch conditions.

Residual coal-fire gas vents form steep thermal and geochemical gradients that create sharply distinct microbial habitats over short distances. We compared the microbial communities of two microhabitats at a residual vent near Kuitun City, Xinjiang: BS1, a gas-emitting fracture at 64 °C, and BS2, adjacent cooler sediment at 43 °C. BS1 had pH 6.8 and total sulfur 5.86 g/kg, whereas BS2 had pH 8.4 and total sulfur 1.90 g/kg. Illumina sequencing of the 16S rRNA gene V3–V4 region yielded 52,327 and 64,212 merged read pairs retained for downstream analyses for BS1 and BS2, respectively. BS1 contained fewer observed amplicon sequence variants (ASVs; 524 versus 1366) and lower Shannon diversity (5.626 versus 6.588). Chloroflexota dominated both communities but was more abundant in BS1 (43.83% versus 36.33%), whereas BS2 contained larger Proteobacteria and Bacteroidota fractions. BS1 was enriched in Pyrinomonas, unclassified Chloroflexota, unclassified Anaerolineae, and Thermorudis, while BS2 was enriched in Thermogemmatispora, Massilia, and Arthrobacter. At this vent, the hot fracture therefore supported a lower-diversity, Chloroflexota-enriched community, whereas cooler sediment supported a richer and more compositionally diverse community. Together with the mineralogical observations, these results reveal sharp site-scale partitioning of bacterial assemblages across a coupled thermal-pH-sulfur gradient.