The synthesis of sulfur-doped activated coke (SAC) using SO₂ as an activator enables simultaneous desulfurizer production and sulfur resource utilization. This study systematically investigated the evolution of carbon properties through sulfur doping and the enhanced desulfurization mechanism through experiments and density functional theory (DFT) calculations. The results demonstrated that SO₂ was primarily converted to elemental sulfur (maximum yield: 92.17 %) via redox reactions with carbon, while doped sulfur mainly existed as thiophene and oxidized sulfur groups (maximum doping: 18.92 wt%). Surface sulfur doping modified carbon's physicochemical properties and produced unique saddle-shaped SO₂ adsorption curves. Transient experiments and DFT calculations revealed enhanced hydrophilicity through strengthened H₂O interactions with sulfur-containing groups (the maximum adsorption energy of H₂O reached −58.70 kJ/mol, 2.64 times that of pristine sulfur-free carbon), which promoted H₂SO₄ migration in micropores via concentration-gradient diffusion to enhance desulfurization. This work provided both a waste-to-resource strategy for desulfurizer preparation and atomic-level insights into the desulfurization enhancement mechanism of SAC, offering design principles for advanced carbon materials in flue gas purification.

Herein, we study the influences of the laser-exposed volume and the irradiation position on the nonphotochemical laser-induced nucleation (NPLIN) of supersaturated potassium chloride solutions in water. The effect of the exposed volume on the NPLIN probability was studied by exposing distinct milliliter-scale volumes of aqueous potassium chloride solutions stored in vials at two different supersaturations (1.034 and 1.050) and laser intensities (10 and 23 MW/cm²). Higher NPLIN probabilities were observed with increasing laser-exposed volume as well as with increasing supersaturation and laser intensity. The measured NPLIN probabilities at different exposed volumes are questioned in the context of the dielectric polarization mechanism and classical nucleation theory. No significant change in the NPLIN probability was observed when samples were irradiated at the bottom, top, or middle of the vial. However, a significant increase in the nucleation probability was observed upon irradiation through the solution meniscus. We discuss these results in terms of mechanisms proposed for NPLIN.

Non-photochemical laser-induced nucleation (NPLIN) has emerged as a promising primary nucleation control technique offering spatiotemporal control over crystallization with potential for polymorph control. So far, NPLIN was mostly investigated in milliliter vials, through laborious manual counting of the crystallized vials by visual inspection. Microfluidics represents an alternative to acquiring automated and statistically reliable data. Thus we designed a droplet-based microfluidic platform capable of identifying the droplets with crystals emerging upon Nd:YAG laser irradiation using the deep learning method. In our experiments, we used supersaturated solutions of KCl in water, and the effect of laser intensity, wavelength (1064, 532, and 355 nm), solution supersaturation (S), solution filtration, and intentional doping with nanoparticles on the nucleation probability is quantified and compared to control cooling crystallization experiments. Ability of dielectric polarization and the nanoparticle heating mechanisms proposed for NPLIN to explain the acquired results is tested. Solutions with lower supersaturation (S = 1.05) exhibit significantly higher NPLIN probabilities than those in the control experiments for all laser wavelengths above a threshold intensity (50 MW/cm²). At higher supersaturation studied (S = 1.10), irradiation was already effective at lower laser intensities (10 MW/cm²). No significant wavelength effect was observed besides irradiation with 355 nm light at higher laser intensities (≥50 MW/cm²). Solution filtration and intentional doping experiments showed that nanoimpurities might play a significant role in explaining NPLIN phenomena.