Proper disposal of industrial brine has been a critical environmental challenge. Driven by the even-tightening environment protection regulations, the Zero-Liquid-Discharge (ZLD) has gradually become a mandatory option for brine disposal, but its application is limited by intensive energy consumption. The recent development of solar crystallizers provides a new strategy to achieve ZLD brine disposal. However, the research on solar crystallizers, employing photothermal material to convert solar energy to heat for interfacial brine evaporation and crystallization, is still at the early stage. This dissertation thoroughly investigated solar crystallizer-based ZLD technology in a broad scientific and application context. The scaling formation while treating real brine, which has been the major barrier to the application of solar crystallizer, was confirmed first with a solar crystallizer device. With a rational designed anti-scaling mechanism, the scaling-free crystallization behavior and stable high water evaporation rate of 2.42 kg m-2h-1 was achieved when treating real seawater brine. After verifying the feasibility of solar crystallizer towards real brine treatment, its performance was further improved by integrating convective airflow, which provided considerable environmental energy for water evaporation. Both experiment results and COMSOL simulation results confirmed that the maximum environmental energy harvesting can be achieved with the proper size of the solar crystallizer. At last, this dissertation pioneered a novel concept of integrating the adsorption process into solar crystallizer for simultaneously ZLD brine treatment and potassium extraction. Owing to the special ion concentration behavior of solar crystallizer, the adsorption capacity and selectivity coefficient of absorbent was enhanced by 19.5% and 48.8%, respectively, comparing with traditional bulk adsorption. This dissertation potentially unlocks a new generation of ZLD technology with low carbon footprint and source recovery.
Chenlin Zhang is a Ph.D. candidate at the King Abdullah University of Science and Technology (KAUST) under Prof. Peng Wang's supervision. His research focuses on solar-driven processes for water evaporation. His doctoral work lies in the design of new generation solar crystallizers for brine treatment with zero-liquid-discharge (ZLD) and specifically on the seawater desalination brine. He earned a B.Sc. in chemical engineering at Zhejiang University. He obtained his M. Sc. in chemical engineering at Beijing Research Insititute of Chemical Industry while committed to finding a more sustainable solution for ZLD brine treatment.