| Currently,solar energy is one kind of the most popular renewable energy sources and can be used as the basic energy source on Earth anywhere.Solar collectors are a simple and efficient way to utilize solar energy,and their thermal performance depends on the photothermal conversion ability of the collecting medium.Nanofluids have received widespread attention due to their excellent photothermal performance.Waste toner is often overlooked in the treatment of waste printers and toner cartridges,incinerated and buried together with the printers and toner cartridges,causing serious soil pollution.The release of toxic gases can cause irreversible harm to people’s bodies.Therefore,proper disposal of waste toner is crucial.In response to this issue,this article proposes the application of waste toner in photothermal conversion,providing new ideas for the treatment and reuse of waste toner,and also providing new choices for the collection medium of solar collectors.This study used a two-step method to prepare toner nanofluids,observed the morphology of particles in toner and toner nanofluids,evaluated their dispersion stability,and studied the effects of different mass fractions,wavelengths,and base solutions on the absorbance,transmittance,and extinction coefficient of toner nanofluids;Conduct photothermal conversion experiments to study the effects of different lighting conditions,mass fractions,and base solutions on the photothermal conversion performance of toner nanofluids,and calculate the photothermal conversion efficiency;Based on the characteristic that toner contains ferromagnetic particles,this study investigates the effects of different lighting conditions,magnetic field types,intensities,and directions on the photothermal conversion performance of toner nanofluids,and calculates the photothermal conversion efficiency.The results indicate that ink powder nanofluids have good stability by simply dispersing them through physical means;As the mass fraction increases,the absorbance of the ink powder nanofluid increases at the same wavelength,the transmittance decreases,and the extinction coefficient increases;In the visible near-infrared wavelength range,the absorbance and extinction coefficient of toner nanofluids decrease with the increase of wavelength,while the transmittance increases with the increase of wavelength;The photothermal conversion performance of toner nanofluids first increases and then decreases with the increase of mass fraction,showing the same pattern under different base solutions and lighting conditions.The photothermal conversion efficiency reaches its peak in the early stage of lighting,and continues to decrease with the increase of lighting time;In a constant magnetic field,the photothermal conversion performance of toner nanofluids first increases and then decreases with the increase of magnetic field intensity,and increases with the angle between the magnetic field direction and the incident light direction.When the magnetic field direction is perpendicular to the incident light direction,the photothermal conversion performance is the best;The oscillating field can increase the heating rate of toner nanofluids,but has little effect on the final temperature rise;Under different lighting conditions,the photothermal conversion performance of toner nanofluids in a constant magnetic field exhibits the same pattern as the variation of field strength,and the variation of photothermal conversion efficiency with time is the same as in the absence of a magnetic field. |
