Natural clinoptilolite was modified by NaCl-firing to produce modified clinoptilolite. Afterwards, the modified clinoptilolite was regulated by LaCl 3 to produce composite clinoptilolite. Modified clinoptilolite and composite clinoptilolite were used to adsorb ammonia-nitrogen and phosphates from wastewater. The modified clinoptilolite and composite clinoptilolite had high sorption efficiency and removal performance. The ammonia-nitrogen and phosphate removal rate of the modified clinoptilolite reached 96.46 % and the phosphate removal rate of the composite clinoptilolite reached 86.26 %. Furthermore, the structure was characterized by SEM, EDS, XRD, IR, and N 2 -porosimetry analyses. Results showed that the surface of modified clinoptilolite became loose and some pores appeared, which increased the specific surface area. In addition, total pore volume, micropore area and average pore width increased after modification by NaCl firing and LaCl 3 regulation, where in the micropore area exhibitedthe highest increase. The modification process did not change the overall skeletal structure and structural holes for both the modified clinoptilolite and the composite clinoptilolite. The main components were Si, Al, and O. The Na ion content of the modified clinoptilolite increased from 0.77 % to 2.45 % and the La ion content of composite clinoptilolite increased from 0 % to 2.52 %. The modification and regulation mechanisms were based on the Na þ replace Ca 2þ and Mg 2þ of clinoptilolite. Hydrous lanthanum oxide could be loaded only to the surface of clinoptilolites. In addition, the ion-exchange capacity of both the modified clinoptilolite and the composite clinoptilolite improved compared with natural clinoptilolite.

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The deterioration of concrete structures after fires has been widely concerned. The purpose of this paper is to study the influence of high temperature on the mechanical properties and pore structure of hybrid basalt–polypropylene fiber fly ash concrete. The mechanical properties and damage amount of hybrid basalt–polypropylene fiber concrete with different content of fly ash (FA0, FA10, FA20, and FA30) at different temperatures (20, 200, 400, 600, and 800 °C) were investigated. Additionally, the pore structure test was conducted, and the relationship between pore structure parameters and macromechanical properties was analyzed. The microstructure at different temperatures was observed by scanning electron microscopy (SEM) images. Finally, the main pore structure parameters affecting compressive strength, tensile strength, and damage amount were determined by using the gray correlation entropy method. From the results, after natural cooling at 200 °C, the compressive and tensile strength of concrete was slightly higher than that at room temperature, and it should be noticed that the FA10 concrete specimen showed better mechanical properties at different temperatures compared with other specimens. The increase in air content, spacing factor, and average chord length weakened the strength of concrete, while the increase in specific surface area had a positive impact on the compressive and tensile strength of concrete. The microstructure of FA10 at high temperature was better than that of FA0. The specific surface area was the main factor affecting the compressive and tensile strength, while the main factor affecting the damage amount was the spacing factor, followed by the average chord length.