Self-assembled core-shell polydopamine@MXene with synergistic solar absorption capability for highly efficient solar-to-vapor generation

As a renewable and environment-friendly technology for seawater desalination and wastewater purification, solar energy triggered steam generation is attractive to address the long-standing global water scarcity issues. However, practical utilization of solar energy for steam generation is severely restricted by the complex synthesis, low energy conversion efficiency, insufficient solar spectrum absorption and water extraction capability of state-of-the-art technologies. Here, for the first time, we report a facile strategy to realize hydrogen bond induced self-assembly of a polydopamine (PDA)@MXene microsphere photothermal layer for synergistically achieving wide-spectrum and highly efficient solar absorption capability (≈ 96% in a wide solar spectrum range of 250–1,500 nm wavelength). Moreover, such a system renders fast water transport and vapor escaping due to the intrinsically hydrophilic nature of both MXene and PDA, as well as the interspacing between core-shell microspheres. The solar-to-vapor conversion efficiencies under the solar illumination of 1 sun and 4 sun are as high as 85.2% and 93.6%, respectively. Besides, the PDA@MXene photothermal layer renders the system durable mechanical properties, allowing producing clean water from seawater with the salt rejection rate beyond 99%. Furthermore, stable light absorption performance can be achieved and well maintained due to the formation of ternary TiO2/C/MXene complex caused by oxidative degradation of MXene. Therefore, this work proposes an attractive MXene-assisted strategy for fabricating high performance photothermal composites for advanced solar-driven seawater desalination applications.

     

海水淡化技术与太阳能利用

海水淡化是解决水源危机的根本措施，但海水淡化绝不能以牺牲能源为代价；现有的几种海水淡化技术各有优劣，应配套使用；河海大学和南京玻纤院等研制的太阳能加热装置，可以作为海水淡化装置中清洁、无污染的能源。     

Strategies for Improving the Photocatalytic Hydrogen Evolution Reaction of Carbon Nitride-Based Catalysts

Due to the depletion of fossil fuels and their-related environmental issues, sustainable, clean, and renewable energy is urgently needed to replace fossil fuel as the primary energy resource. Hydrogen is considered as one of the cleanest energies. Among the approaches to hydrogen production, photocatalysis is the most sustainable and renewable solar energy technique. Considering the low cost of fabrication, earth abundance, appropriate bandgap, and high performance, carbon nitride has attracted extensive attention as the catalyst for photocatalytic hydrogen production in the last two decades. In this review, the carbon nitride-based photocatalytic hydrogen production system, including the catalytic mechanism and the strategies for improving the photocatalytic performance is discussed. According to the photocatalytic processes, the strengthened mechanism of carbon nitride-based catalysts is particularly described in terms of boosting the excitation of electrons and holes, suppressing carriers recombination, and enhancing the utilization efficiency of photon-excited electron–hole. Finally, the current trends related to the screening design of superior photocatalytic hydrogen production systems are outlined, and the development direction of carbon nitride for hydrogen production is clarified.     

可控碳化废弃聚丙烯制备镍/碳纳米材料用于高效光蒸气转换

利用太阳能实现光蒸气转化是一项极具前景的技术,可应用于海水脱盐和淡水制备等领域.然而,从工业的角度来看,制备低成本、高效率的光热材料仍具有挑战性.本文利用聚离子液体(PIL)和氧化镍(Ni O)作为复合催化剂,实现了聚丙烯(PP)的可控碳化,并制备了镍/碳纳米材料(Ni/CNM).研究结果表明,加入微量的PIL可实现对Ni/CNM形貌和织态结构的调控.Ni/CNM由杯状碳纳米管(CS-CNT)和梨形镍纳米颗粒组成,二者在太阳光吸收上的协同作用使得Ni/CNM具有优异的光热转换性能.此外,Ni/CNM具有较高的比表面积和丰富的微/介/大孔,其构建的三维多孔网络可为水和蒸气的高效传输提供通道.光吸收高、水传输快和热导率低等优势,使Ni/CNM的水蒸发速率高达1.67 kg m^-2h^-1,光-蒸气转换效率高达94.9%,且重复使用10次后性能依然保持稳定.该材料同时适用于染料废水、海水和油/水乳化液等水质的纯化.其中,海水中金属离子的去除效率高达99.99%,染料去除率>99.9%.更重要的是,材料的光蒸气转换性能优于最新报道的碳基光热材料.此工作不仅提出了一种可将废弃聚合物转化为先进的金属/碳杂化物的可持续方法,同时也有助于太阳能利用和海水淡化领域的进一步研究.     

大规模海上风电的非并网多元化应用研究——变海上风电场输电上岸为直接输产品上岸的探索

针对海上风电大规模发展成本高、并网难、故障概率高的瓶颈,提出了一种海上大规模风电非并网多元化应用系统。该系统突破海上大规模风电并网的单一应用模式,通过必要的技术创新与集成,将大规模海上风电与高载能产业(如海水淡化、电解水制氢和电解铝等)直接耦合形成一个完整的新系统,变海上风电场输电上岸为直接输产品上岸,不仅破解了大规模、超大规模海上风电应用难题,而且大幅度节省海上风电场投资成本,提高了风电利用效率,具有十分重要的现实和战略意义。     

A 3D‐Structured Sustainable Solar‐Driven Steam Generator Using Super‐Black Nylon Flocking Materials

Solar‐driven evaporation is a promising way of using abundant solar energy for desalinating polluted water or seawater, which addresses the challenge of global fresh water scarcity. Cost‐effectiveness and durability are key factors for practical solar‐driven evaporation technology. The present cutting‐edge techniques mostly rely on costly and complex fabricated nanomaterials, such as metallic nanoparticles, nanotubes, nanoporous hydrogels, graphene, and graphene derivatives. Herein, a black nylon fiber (BNF) flocking board with a vertically aligned array prepared via a convenient electrostatic flocking technique is reported, presenting an extremely high solar absorbance (99.6%), a water self‐supply capability, and a unique salt self‐dissolution capability for seawater desalination. Through a carefully designed 3D structure, a plug‐in‐type BNF flocking board steam generator realizes a high evaporation rate of 2.09 kg m^?2 h^?1 under 1 kW m^?2 solar illumination, well beyond its corresponding upper limit of 1.50 kg m^?2 h^?1 (assuming 100% solar energy is being used for evaporation latent heat). With the advantages of high‐efficiency fabrication, cost‐effectiveness, high evaporation rate, and high endurance in seawater desalination, this 3D design provides a new strategy to build up an economic, sustainable, and rapid solar‐driven steam generation system.     

激光微纳制造太阳能海水淡化材料研究进展

海水淡化技术在解决水资源短缺的问题上起着重要的作用,其中太阳能海水技术的研究#更是备受关注.激光微纳制造技术作为一种先进、便捷的加工方法,近年来在制备海水淡化材料领域取得了一定的研究成果.本文以太阳能海水淡化技术以及激光加工技术作为研究背景,根据研究材料的多样性,从材料的构成本质出发,将近年来关于激光微纳制造海水淡化材...     

Tackling the water-energy nexus: an assessment of membrane distillation driven by salt-gradient solar ponds

Although the costs of desalination have declined, traditional desalination systems still need large amounts of energy. Recent advances in direct contact membrane distillation can take advantage of low-quality renewable heat to desalinate brackish water, seawater, or wastewater. In this work, the performance of a direct contact membrane distillation (DCMD) system driven by salt-gradient solar ponds was investigated. A mathematical model that couples both systems was constructed and validated with experimental data available in the scientific literature. Using the validated model, the performance of this coupled system in different geographical locations and under different operational conditions was studied. Our results show that even when this coupled system can be used to meet the future needs of energy and water use in a sustainable way, it is suitable for locations between 40°N and 40°S that are near the ocean as these zones have enough solar radiation, and availability of excess water and salts to operate the coupled system. The maximum freshwater flow rates that can be obtained are on the order of 3.0 L d^?1 per m² of solar pond (12.1 m³ d^?1 acre^?1), but the expected freshwater production values are more likely to be on the order of 2.5 L d^?1 per m² of solar pond (10.1 m³ d^?1 acre^?1) when the system operates with imperfections. The coupled system has a thermal energy consumption of 880 ± 60 kWh per m³ of distillate, which is in the range of other membrane distillation systems. Different operational conditions were evaluated. The most important operating parameters that influence the freshwater production rates are the partial pressure of air entrapped in the membrane pores and the overall thermal efficiency of the coupled system. This work provides a guide for geographical zone selection and operation of a membrane distillation production system driven by solar ponds that can help mitigate the stress on the water-energy nexus.     

海水淡化技术在沿海电厂的应用浅析

简要介绍了海水淡化技术及其应用现状,仔细分析了沿海电厂应用海水淡化技术的可行性、必要性和需要解决的主要问题,并给出了有关综合利用的建议。     

硝酸熔盐储热材料在太阳能利用中的研究进展

随着全球经济的快速发展,能源危机日渐凸显,太阳能作为可再生能源的一种,越来越受到人们的重视.因此,如何高效利用太阳能资源值得深究.熔盐具有良好的蓄热特性,在石化、电池及冶金行业中发挥着很大的作用,尤其可以作为传热蓄热介质应用于太阳能热发电和太阳能制氢中.其中硝酸盐的特性较为适合用于熔盐储热材料.主要针对硝酸熔融盐体系,一是介绍了硝酸熔融盐体系在太阳能方面的应用,二是介绍了国内外学者对此体系的物化性质研究,如工作温度范围、热力学性质及热稳定性等.通过对比,总结了不同混合熔融盐各项性能的异同.指出了硝酸熔融盐性能深入研究的方向,为硝酸熔盐在能源开发利用和环境保护等方面发挥更重要的作用提供了重要参考.     

Sustainable multi-period electricity planning for Iskandar Malaysia

This paper presents the current situation and projected planning of the electricity generation sector for Iskandar Malaysia by implementing a model to optimise the cost, utilise the usage of available renewable energy sources, and achieve carbon dioxide reduction targets. This Mixed Integer Linear Programming model was developed with the main objective of minimising the total cost of electricity generation, taking into consideration energy demand, reserve margin, electricity generation, peak and base generation, resource availability, and CO₂ emission. Data for the year 2013 were forecasted until 2025 to illustrate the analysis for this study, and are represented via four scenarios. This optimal model is capable of balancing types of fuel and switching coal plants to natural gas power plants. It also enhances the use of renewable energy (RE) to meet CO₂ emission targets. The model is further integrated with several other considerations related to energy systems, such as suitability of power plants as peak or base plants, RE resource availability, intermittency of solar power, losses during transmission, fuel selection for biomass, decision to retrofit existing coal power plant to NG power plant, and construction lead time of power plants. The results for this study determined that the optimal scenario is Scenario 3 (CS3). This research proves that Iskandar Malaysia can reduce CO₂ emission by 2025 via utilisation of RE. This model is generic and can be applied to any case study, which would be useful for assisting government policy-making.     

电厂宽负荷运行下蒸汽喷射器对低温多效蒸馏系统的影响

淡水资源匮乏问题日益严重,火电厂耦合低温多效蒸馏（low-temperature multi-effect distillation,LT-MED）海水淡化技术因可有效降低制水成本而被广泛利用。利用Ebsilon软件对某电厂和低温多效蒸馏海水淡化耦合系统进行建模,分析了电厂宽负荷下蒸汽喷射器对水电联产系统热经济性的影响规律。研究结果表明：基于单级蒸汽喷射器的水电联产系统,以电厂75% THA工况设计下的蒸汽喷射器的性能最佳。对于带两级蒸汽喷射器的水电联产系统,当电厂负荷在75% THA工况时系统的制水电耗量相比单级蒸汽喷射器系统降低了13.65%,并且电厂负荷在50% THA工况以上时,带两级蒸汽喷射器系统的制水电耗量较单级蒸汽喷射器系统的低。     

Engineering Metal–Phenolic Networks for Solar Desalination with Directional Salt Crystallization

Solar desalination is one of the most promising strategies to address the global freshwater shortage crisis. However, the residual salt accumulated on the top surface of solar evaporators severely reduces light absorption and steam evaporation efficiency, thus impeding the further industrialization of this technology. Herein, a metal–phenolic network (MPN)-engineered 3D evaporator composed of photothermal superhydrophilic/superhydrophobic sponges and side-twining hydrophilic threads for efficient desalination with directional salt crystallization and zero liquid discharge is reported. The MPN coatings afford the engineering of alternating photothermal superhydrophilic/superhydrophobic sponges with high heating efficiency and defined vapor escape channels, while the side-twining threads induce site-selective salt crystallization. The 3D evaporator exhibits a high and stable indoor desalination rate (≈2.3 kg m⁻² h⁻¹) of concentrated seawater (20 wt%) under simulated sun irradiation for over 21 days without the need for salt crystallization inhibitors. This direct desalination is also achieved in outdoor field operations with a production rate of clean water up to ≈1.82 kg m⁻² h⁻¹ from concentrated seawater (10 wt%). Together with the high affinity and multiple functions of MPNs, this work is expected to facilitate the rational design of solar desalination devices and boost the research translation of MPN materials in broader applications.     

Hierarchical Graphene Foam for Efficient Omnidirectional Solar–Thermal Energy Conversion

Efficient solar–thermal energy conversion is essential for the harvesting and transformation of abundant solar energy, leading to the exploration and design of efficient solar–thermal materials. Carbon‐based materials, especially graphene, have the advantages of broadband absorption and excellent photothermal properties, and hold promise for solar–thermal energy conversion. However, to date, graphene‐based solar–thermal materials with superior omnidirectional light harvesting performances remain elusive. Herein, hierarchical graphene foam (h‐G foam) with continuous porosity grown via plasma‐enhanced chemical vapor deposition is reported, showing dramatic enhancement of broadband and omnidirectional absorption of sunlight, which thereby can enable a considerable elevation of temperature. Used as a heating material, the external solar–thermal energy conversion efficiency of the h‐G foam impressively reaches up to ≈93.4%, and the solar–vapor conversion efficiency exceeds 90% for seawater desalination with high endurance.     

Correlation analysis of small wind–solar–biomass hybrid energy system installed at RGTU Bhopal, MP (India)

The perspective of this paper represents all types of correlation existing among the various renewable power sources in the hybrid system to find out its feasibility. Among the different energy alternatives available, the wind energy system clubbed with solar photo voltaic panels and biomass gasifier for the production of electricity is found more suitable. As wind, solar and biomass hybrid energy systems stand out distinctly for their use in tropical regions. Keeping this in view a statistical correlation analysis of the said hybrid energy system has been evolved for a remote area (wind and solar data of which are collected from weather monitoring station installed at University Institute of Technology, Bhopal, India).     

Optimal operation of a distributed energy generation system for a sustainable palm oil-based eco-community

The palm oil industry potentially can be environmentally sustainable through utilizing the vast availability of biomass residues from palm oil mills as renewable energy sources. This work addresses the optimal operation of a combined bioenergy and solar PV distributed energy generation system to meet the electricity and heat demands of an eco-community comprising a palm oil mill and its surrounding residential community. A multiperiod mixed-integer linear programming planning and scheduling model is formulated on an hourly basis that optimally selects the power generation mix from among available biomass, biogas, and solar energy resources with consideration for energy storage and load shifting. A multiscenario approach is employed that considers scenarios in the form of many possible weather conditions and various energy profiles under varying mill operation modes and residential electricity consumption. The proposed approach is demonstrated on a realistic case study for a palm oil mill in the Iskandar Malaysia economic development region. The computational results indicate that biomass-based resource is the preferred renewable energy to be implemented due to the high cost associated with solar PV. As well, load shifting and energy storage can be feasibly deployed for demand peak shaving particularly for solar PV systems.     

面向促进新能源消纳的源网荷贡献度分解算法

解决我国新能源消纳矛盾，需要从电源、电网、负荷等环节因素入手，综合施策、系统优化，有效提升新能源消纳能力，但因侧重研究源网荷因素共同作用效果，缺乏对促进新能源消纳时每种因素的实际贡献度分析。为此，从规划角度，基于电力系统生产模拟构建不同的源网荷因素发展情景，分别根据灵敏度法和Shapley值法对各因素在促进新能源消纳能力中的贡献度进行分解，并结合算例充分比较两种方法差异。分析结果表明，灵敏度法针对特定情景判断某因素的消纳贡献度，适合针对既定发展阶段给出措施清单；Shapley值法基于全部发展情景对各因素贡献度进行综合加权，更适合考察从现状到规划水平年的发展全过程。     

偏远岛礁就地供水保障模式分析

分析了偏远岛礁依靠大陆船运送水的远距离供水保障模式在复杂军事斗争环境和台风频发环境存在的主要问题,提出了能提高岛礁独立生存能力的淡水自给自足的保障模式,重点探讨了利用雨水收集和可再生能源发电制水这两种方式解决偏远岛礁就地供水保障问题的特点、互补性、具体方式和技术途径。研究表明,采用"珊瑚沙滩浅层暗湖雨水收集利用系统"和"光伏直接供能反渗透海水淡化系统"这两种具体的淡水就地保障模式具有很高的发展潜能,特别是其联合工作模式具有较强的互补性和可靠性,适合在偏远岛礁推广应用。     

风光水多能源电力系统互补智能优化运行策略

高比例可再生能源接入电网,采用风光水互补发电可以提供平滑和稳定的电力供应。针对风光水多能源电力系统,采用大数据和人工智能技术,提出基于随机规划的短期优化运行方法。首先,基于变分自编码器（variational autoencoder,VAE）提出了可再生能源场景生成方法,能够生成符合可再生能源出力特性的多样化场景,并精确刻画可再生能源出力的相关性。其次,基于场景法建立了风光水互补短期优化运行模型,并采用分段线性化的方法将多种非线性约束转化为线性约束,可以保证模型精度的同时实现快速求解。最后,通过对雅砻江下游风光水发电基地的算例仿真,验证了所提的智能优化运行策略的有效性。     

Energy efficiency of RO and FO–RO system for high-salinity seawater treatment

Forward osmosis (FO) has been proposed as an alternative method for seawater desalination, wherein reverse osmosis (RO) membrane technology is used for regeneration of the draw solution. Previous studies have indicated that a standalone RO unit is more energy efficient than an FO–RO system, and as such it was recommended that an FO–RO system is best employed only for the desalination of high-salinity seawaters. This study examined FO–RO applicability in more detail by examining the impact of seawater salinity, impact of an energy recovery device (ERD), and the effect of membrane fouling. For comparison purposes, the performance of the FO process was improved to minimize the impact of concentration polarization and optimize the concentration of draw solution. Model calculations revealed that FO–RO is more energy efficient than RO when no ERD was employed. However, results showed that there was no significant difference in the power consumption between the FO–RO system and the RO unit at high seawater salinities particularly when a high-efficiency ERD was installed. Moreover, the FO–RO system required more membrane area than a conventional RO unit which may further compromise the FO–RO desalination cost.