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A novel multi-hydroxyl-containing gemini surfactant (G16) is first designed for modifying silica precursors (SiNPs), with the purpose of fabricating organic adsorbents targeted at methyl orange (MO). The purity of G16 and structural character of the resultant G16-SiNPs are unveiled through Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetry-derivative thermogravimetry, scanning electron microscopy, and surface analysis (BET). Compared with SiNPs, G16-SiNPs exhibit enhanced hydrophobicity, enlarged interlayer spacing, and increased thermal weight losses with the modifier availability reaching as high as 100%. Enhanced MO adsorption is obtained from the higher adsorption capacity of G16-SiNPs (401.88 mg/g) than SiNPs (64.72 mg/g), which is more effective than most of the existing silica-based adsorbents. Pseudo-second-order and Langmuir models conform to all adsorption processes, indicating that the adsorption mainly relies on the availability of adsorption sites and characterized by a homogeneous adsorption form. By combining the experimental study and theoretical calculation methods, it can be demonstrated that the as-synthesized adsorbent G16-SiNPs own multi-active sites that contribute to multi-adsorption mechanisms. The partition process, electrostatic interactions, and OH−π interactions are all responsible for the adsorption performance of G16-SiNPs. This study throws light on the exploration of the superb MO adsorbent in aspects of not only the novel structured modifier and precursor but also theoretical analysis for gaining insights into the adsorption mechanism.

Biomass activated carbon has been widely used in the field of wastewater treatment because of its unique properties, such as high specific surface area and porosity, good adsorption capacity, good mechanical strength, rich functional groups and thermal stability. In this work, highland barley straw is recycled and made into activated carbon using hydrothermal carbonization and alkaline activation processes in which the dependence of the product properties on the activation temperature, as one of the critical parameters, is intensively investigated. Under the optimum conditions at an activation temperature of 1100 °C, activated carbon in the form of mesoporous structure and polycrystalline graphite was produced with a specific surface area as large as 1906 m2/g, which is superior to that of commercial products. To investigate the absorption capacity of the prepared samples for pollutants in water, such as heavy metals and organics, potassium dichromate and methylene blue were utilized as the simulated pollutants. The removal efficiency of Cr6+ and methylene blue in water reached 90.3 % within eight hours and 87.7 % within four hours, respectively, and this demonstrated an excellent absorption capacity for activated carbon converted from agricultural waste. Th e successful fabrication of activated carbon with a super large specific surface area and remarkable adsorption ability derived from highland barley straw through a hydrothermal carbonization and alkaline treatment demonstrated the feasibility of the “turning waste into wealth” recycling strategy. It has also shown great potential for use in environmental protection applications, especially for water purification.

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With the improvement of people’s living standard, diverse home decoration has become popular. However, it results in indoor hazardous gas emission, especially formaldehyde, bringing harm to people’s health. To address this issue, one positive strategy is to remove the hazardous volatile organic compounds through environment friendly nanomaterials. Nano-TiO2 is such a kind of semiconductor material, which can decompose the volatile pollutants via photocatalytic process. In this work, the removal of indoor volatile pollutants by applying home-made nano-TiO2 was studied. The dependence of treatment efficiency of indoor formaldehyde on varying flow rate, coating times, humidity and temperature was systematically investigated. As a result, the highest purification efficiency was achieved when it was coated three times at the relative humidity of 50%. The faster the flow rate, the higher the air purification efficiency. Temperature is also an important factor affecting degradation efficiency, and the degradation has peaked at 22°C. This study demonstrates the effective removal of indoor volatile organic compounds via green nano-TiO2 coating at low cost, and paves way for nanomaterials in applications of indoor environment improvement.