The conventional membrane distillation (MD) process is accompanied by large energy consumption, low thermal efficiency and inevitable requirements of centralized infrastructures, which impede its practical applications, especially in the offshore and remote off-grid areas. Thanks to the rapid development of efficient photothermal materials over the last decade, a new photothermal membrane distillation (PMD) process has emerged to harness abundant solar energy and localize heating on the membrane-feed water interface via photothermal effects. Driven by the temperature difference across the PMD membrane, water vapor can be generated on the membrane-feed surface, transported through membrane pores and condensed at permeate side to obtain freshwater, thus tackling the challenge of obtaining clean water using green energy. The PMD process avoids heating the entire bulk feed water and feed transportation from heat units to membrane modules, which save substantial amounts of energy. The interfacial localized heating intrinsically mitigates the temperature polarization across the membrane. The latent heat from vapor condensation can be effectively recovered via multi-level PMD configurations. As great efforts have been made to exploit PMD process, it is imperative to review the state-of-the-art progress of PMD and shed light on its future trend. Here, we briefly illustrate PMD mechanisms and membrane requirements, photothermal materials feasible for developing PMD membranes along with their light-to-heat mechanisms. This is followed by reviewing diverse approaches to prepare PMD membranes, which are classified into one-step fabrication and multi-step modification methods. Comprehensive discussion about PMD membrane performance in different configurations and their small pilot-scaled applications are provided. The effects of operational parameters and module designs are discussed in Section 6. Finally, the current challenges and future perspectives of PMD process are emphasized with the aim of providing guidance for future works.

传统的膜蒸馏（MD）工艺伴随着能耗大、热效率低和不可避免的集中基础设施的要求，阻碍了其实际应用，特别是在海上和偏远离网地区。由于过去十年中高效光热材料的快速发展，出现了一种新的光热膜蒸馏 (PMD) 工艺，以利用丰富的太阳能并通过以下方式在膜-给水界面上局部加热光热效应。在PMD膜两侧温差的驱动下，水蒸气可以在进膜表面产生，通过膜孔输送并在渗透侧冷凝获得淡水，从而解决利用绿色能源获得清洁水的挑战。PMD 工艺避免了加热整个散装给水和从加热单元到膜组件的给水运输，从而节省了大量能源。界面局部加热本质上减轻了跨膜的温度极化。从蒸汽冷凝的潜热可以有效地回收通过多级 PMD 配置。由于已经为开发PMD工艺做出了巨大努力，因此必须回顾PMD的最新进展并阐明其未来趋势。在这里，我们简要说明了 PMD 机制和膜要求，可用于开发 PMD 膜的光热材料及其光热机制。接着回顾了制备 PMD 膜的多种方法，这些方法分为一步制造和多步改性方法。提供了有关不同配置的 PMD 膜性能及其小型中试应用的全面讨论。操作参数和模块设计的影响在第 6 节中讨论。最后，