Periodic deprivation of gaseous hydrogen sulfide affects the activity of the concrete corrosion layer in sewers

Bi-MOF-based point-of-care testing paper for dual-mode detection of H2S

Hydrogen sulfide (H2S) is noxious gas and significantly threatens human health. Herein, a Bi-based metal-organic frameworks (Bi-MOFs) based paper analysis device (PAD) has been developed for rapid and effective dual-mode detection of H2S. The dominant H2S sensing mechanism is explored. The H2S can react with Bi-MOF to form bismuth sulfide (Bi2S3) MOF (Bi2S3-MOF), changing the color of PAD from white to black. The distinguish color change makes it very convenience for visible detection. Meanwhile, the generated Bi2S3-MOF exhibits excellent photothermal property, endowing it possible for photothermal imaging detection. In this regard, the PAD boasts a wide linear detection range of 0-40 μM for H2S with an impressively low limit of detection (LOD) (0.23 μM). The constructed sensing system is demonstrated with outstanding selectivity and storage stability. Satisfied recovery is reached for H2S detection in diverse real samples. Interestingly, the PAD can be used as intelligent label for assessing meat freshness by monitor H2S release from meat under different storage temperatures. With integration capabilities of smartphones, the portable and user-friendly PAD offers a simple and rapid solution for on-the-go detection of H2S in food and environment. The investigation provides an instructive way for environment monitoring and food safety guarding.

Durability Performance and Corrosion Mechanism of New Basalt Fiber Concrete under Organic Water Environment

Under corrosive environments, concrete material properties can deteriorate significantly, which can seriously affect structural safety. Therefore, it has important engineering applications to improve the durability performance at a lower economic cost. This paper proposes a new, highly durable concrete using inexpensive construction materials such as basalt fiber, sodium methyl silicate, and inorganic aluminum salt waterproofing agent. With the massive application of sewage treatment projects, the problem of concrete durability degradation is becoming more and more serious. In this paper, five types of concrete are developed for the sewage environment, and the apparent morphology and fine structure of the specimens after corrosion in sewage were analyzed. The density, water absorption, and compressive strength were measured to investigate the deterioration pattern of concrete properties. It was found that ordinary concrete was subject to significant corrosion, generating large deposits of algae on the surface and accompanied by sanding. The new concrete showed superior corrosion resistance compared to conventional concrete. Among other factors, the inorganic aluminum salt waterproofing agent effect was the most prominent. The study found that the strength of ordinary concrete decreased by about 15% in the test environment, while the new concrete had a slight increase. Comprehensive evaluation showed that the combination of basalt fiber and inorganic aluminum salt waterproofing agent had the best effect. Its use is recommended.

Superhydrophobic Civil Engineering Materials: A Review from Recent Developments

Superhydrophobic surfaces have drawn attention from scientists and engineers because of their extreme water repellency. More interestingly, these surfaces have also demonstrated an infinite influence on civil engineering materials. In this feature article, the history of wettability theory is described firstly. The approaches to construct hierarchical micro/nanostructures such as chemical vapor deposition (CVD), electrochemical, etching, and flame synthesis methods are introduced. Then, the advantages and limitations of each method are discussed. Furthermore, the recent progress of superhydrophobicity applied on civil engineering materials and its applications are summarized. Finally, the obstacles and prospects of superhydrophobic civil engineering materials are stated and expected. This review should be of interest to scientists and civil engineers who are interested in superhydrophobic surfaces and novel civil engineering materials.