Novel-modified magnetic multi-walled carbon nanotubes (MMWCNTs) were synthesized via evaporating acid purification and co-precipitation method. MMWCNTs were used for simultaneously removing lead and zinc ions from aqueous solutions. Transmission electron microscope, field emission scanning electron microscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy (XPS), and magnetization curve showed the morphology, composition, surface functional groups, and magnetic properties of MMWCNTs. Then, the adsorption effects were investigated by times, pH, and adsorbent dosages. The results showed that Fe₃O₄ of approximate 10 nm successfully grafted on the surface of MWCNTs. The results of XRD, energy-dispersive X-ray spectroscopy, and XPS further confirmed that the iron oxides were Fe₃O₄. Adsorption data were analyzed with Lagergren pseudo-first-order, pseudo-second-order kinetic, intraparticle diffusion, and liquid film diffusion models. Langmuir isotherm model showed the maximum adsorption capacities as 67.25 and 3.759 mg/g for lead and zinc ions, respectively. These results indicated that MMWCNTs may be a promising candidate for removing heavy metal ions from aqueous solutions.

The effect of temperature on scale inhibition and adsorption properties for Pb²⁺ and phenol was studied under the synergistic effect of the magnetic field and the adsorbent. The sulfhydryl and amino-modified graphene oxide/oxidized multiwalled carbon nanotubes (NH₂-SH-GO/o-MWCNTs) were synthesized and applied as the adsorbent. Additionally, changes in pH, conductivity, molecular activation energy, the relative variation of intramolecular energy and the relative variation in the proportion of free water, and adsorption capacity of the adsorbent were studied under different temperatures of circulating water. The relative variation of the proportion of free water increased with the increasing temperatures. The above results indicated that higher temperature would be detrimental to scale inhibition. The higher the temperatures, the lower the intramolecular energies. And the more stable molecules are formed in the circulating water. Thus, the results reduced the tendency to scale formation. The increased temperatures promoted the adsorption capacity of the adsorbent for Pb²⁺ and phenol. The adsorption process for Pb²⁺ and phenol conformed to the pseudo-second-order kinetic model and Freundlich isotherm model under the synergistic effect of magnetic field and NH₂-SH-GO/MWCNTs. After five cycles, the adsorption capacities of the adsorbent for Pb²⁺ and phenol separately decreased by 59.86% and 76.36%. The aforementioned results reveal that temperatures can promote the adsorption process for Pb²⁺ and phenol, and the synergistic effect between magnetic field and the adsorbent has a potential application for water treatment.

The blast furnace gas separated by a membrane has a higher content of combustible components. In order to explore its secondary utilization in blast furnace production, numerical simulation is conducted by means of Fluent software, and the model is verified by experimental data. Results show that when the blast furnace gas separated by the membrane is used as pulverized coal carrier gas for blast furnace injection, the gas velocity in the furnace evidently increases, and the maximum injection velocity can reach 279 m s⁻¹. The formed high-temperature zone is closer to the centre of the blast furnace than those in the single injection of pulverized coal and in pulverized coal injection with general blast furnace gas as a carrier gas. The maximum temperature reaches 2610 K. Moreover, the pyrolysis reaction of pulverized coal is in advance, whereas the burnout rate of pulverized coal in the raceway presents a double-peak phenomenon.