College of Water Resources and Architecture Engineering, Northwest A&F University, Yangling, Shaanxi 712100, PR China.
Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi 712100, PR China.
Sci Total Environ. 2024 Nov 15;951:175709. doi: 10.1016/j.scitotenv.2024.175709. Epub 2024 Aug 22.
The mechanism by which algal organic matter (AOM) affects the clogging of ceramic emitters remains unclear, which partially reduces the operational life of agricultural water distribution systems. This paper systematically investigated the clogging phenomenon of ceramic emitters under three different AOM concentrations. The results of irrigation tests revealed that the AOM significantly affects the degree of clogging of ceramic emitters, with higher AOM concentrations leading to faster flow reduction. By analyzing the original irrigation water and effluent and characterizing the clogged emitter surface, it was demonstrated that AOM was intercepted by the ceramic emitter, forming a dense biofilm. Infrared spectroscopy analysis revealed that polysaccharides and humic substances were the main clogging components. The clogging kinetics showed that as the AOM concentration increased, the clogging of the filter cake layer gradually become dominant. Further, the mechanism of interaction between AOM and silica ceramic emitters was explored from a microscopic perspective using molecular dynamics (MD) simulation with bovine serum albumin (BSA), sodium alginate (SA), and humic acid (HA) as model clogging substances in AOM. The simulation results indicated a strong interaction between AOM molecules and silica molecules dominated by electrostatic attraction, with the strength of the interaction as SA > HA > BSA. It was hypothesized that early clogging was mainly formed by polysaccharides and humic substances combining with silica molecules, while BSA was retained later by combining with organics on the clogging layer or through size exclusion. This study provides insights into bio-clogging in microporous ceramic emitters and may offer a theoretical basis for developing measures to control emitter clogging.
藻源有机物（AOM）影响陶瓷滴头堵塞的机制尚不清楚，这部分降低了农业配水系统的运行寿命。本文系统研究了三种不同 AOM 浓度下陶瓷滴头的堵塞现象。灌溉试验结果表明，AOM 显著影响陶瓷滴头的堵塞程度，AOM 浓度越高，流量减少越快。通过分析原灌溉水和出水以及堵塞滴头表面的特性，证明 AOM 被陶瓷滴头截留，形成致密的生物膜。红外光谱分析表明，多糖和腐殖质是主要的堵塞成分。堵塞动力学表明，随着 AOM 浓度的增加，滤饼层的堵塞逐渐占主导地位。进一步，通过分子动力学（MD）模拟，以牛血清白蛋白（BSA）、海藻酸钠（SA）和腐殖酸（HA）作为 AOM 中模型堵塞物质，从微观角度探讨了 AOM 与硅质陶瓷滴头之间的相互作用机制。模拟结果表明，AOM 分子与硅分子之间存在以静电吸引为主的强烈相互作用，相互作用强度为 SA>HA>BSA。研究假设早期堵塞主要是由多糖和腐殖质与硅分子结合形成的，而 BSA 则是通过与堵塞层上的有机物结合或通过尺寸排阻作用而被保留下来。本研究为微孔陶瓷滴头中的生物堵塞提供了深入的见解，并可能为开发控制滴头堵塞的措施提供理论依据。
