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The purpose of this study was to use biomass silicon resources in rice straw to synthesize high value-added organosilicon products to solve the problem of low utilization of rice straw and high pollution and energy consumption in the silicon chemical industry. In this work, spirocyclic alkoxysilane was successfully synthesized by an environmentally friendly method from rice straw ash for the first time. The spirocyclic alkoxysilane yield per gram of rice straw ash can reach up to 1.9 g. Spirocyclic alkoxysilane was used to modify silicone resin coating. This coating can withstand 150 applications of friction and still maintain good hydrophobic effect. The maximum water contact angle after friction can reach 104°. This study broadens the application of rice straw. Furthermore, this research lays the foundation for the improvement of energy-saving and emission reduction process of silicon chemical industry.

The scarcity of Li along with its uneven distribution in earth has become a great challenge in the field of electrochemical energy storage. Replacing Li with Na may address the above issues, as Na and Li are very similar in electrochemical characteristics, and Na is abundant in nature with low cost. Herein, the Na-ion conducting gel polymer membranes comprising a 2-HEC/EMITf/NaTf system are synthesized by employing the solution-casting method. The effects of NaTf salt and EMITf ionic liquid on the electrical and electrochemical properties of membranes are investigated. It is demonstrated that the salt is dissolved in the polymer matrix, thereby raising its ionic conductivity (IC), which is further raised by ionic liquid incorporation. The optimized membrane (2-HEC:EMITf:NaTf = 1:0.6:0.15 in mass, named as GPE/Na-3) exhibits a high room-temperature IC of 1.11× 10–3 S cm–1 along with a wide electrochemical stability window of 4.8 V. The membrane also displays sound tensile strength and breaking strain (4.5 MPa and 94.4%, respectively). As the electrolyte, the optimized membrane is combined with graphene electrodes to fabricate a supercapacitor. The supercapacitor presents a high capacitive behavior with an appealing cyclic stability. As evident from the above performance, it is believed that the Na-ion conducting gel polymer membrane possesses potential applications in future Na-ion energy storage devices.

To solve the problems of low utilization of agricultural waste rice husk and heavy metal pollution, this investigation prepared a cheap copper ion adsorbent using rice husk ash (RA). The maximum Cu2+ adsorption capacity was 19.8 mg/g. X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and surface area and porosity analyses were used to characterize the composition and structure of the material of silica-depleted rice husk ash (SDRA). The thermodynamics and kinetics of Cu2+ adsorption by SDRA were studied for their relevance to the adsorption mechanism. The adsorption of copper ions by SDRA was in accordance with the Langmuir model and the pseudo-second-order kinetic model. Furthermore, the increases in specific surface area and oxygen-containing functional groups following silica removal were primarily responsible for SDRA’s enhanced adsorption ability. And this is the first time that Cu2+ adsorbent has been prepared from the by-product of the synthesis of silane from rice husk ash. So, its synthesis cost is very low. Moreover, the preparation technique of SDRA is a revolutionary method of adsorbent creation that is both economical and environmentally benign.

Hydrophobic materials have promising applications. However, fluorine present in hydrophobic materials can lead to health risks and environmental pollution. This study investigated an environmentally friendly route to produce fluorine-free hydrophobic coatings with good wear resistance. Wear-resistant hydrophobic coatings were prepared by introducing different ratios of spirocyclic alkoxysilane into the epoxy resin. Characterization by Fourier transform infrared spectroscopy, water contact angle measurement, scanning electron microscope, tape adhesion test, and abrasion testing showed that the multi-methyl group and double-ring rigid skeleton structure of spirocyclic alkoxysilane can remarkably improve the hydrophobic performance and wear resistance of the epoxy resin. The modified hydrophobic coatings can withstand more than 1600 instances of controlled rubbing. Furthermore, the maximum water contact angle can reach 110° after substantial abrasion. The novelty of the work is that the authors successfully synthesized spirocyclic alkoxysilane for the first-time using corn straw ash. The prepared spirocyclic alkoxysilane was then used as a modifier to prepare hydrophobic epoxy resin coating. This approach can broaden the utilization of corn straw ash. Therefore, this method can achieve a green and low-cost preparation of wear-resistant hydrophobic coatings without the introduction of fluorine.

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