In Situ Growth Synthesis of the CNTs@AC Hybrid Material for Efficient Nitrate-Nitrogen Adsorption

Abstract

Nitrate-nitrogen (NO 3 −N) is a common pollutant in aquatic environments and causes many environmental issues and health problems. This study successfully applied the activated AC@CNT composite synthesized by CNTs in-situ growth and post-treated by myristyltrimethylammonium bromide (MTAB) for NO 3 −N adsorption from wastewater. The results show that the highest NO 3 −N adsorption capacity of AC@CNTs-M was 14.59 mg•g −1 . The in-situ growth of CNTs gave a higher specific surface area and more mesoporous volume, while MTAB uniformly occupied part of the pore structure after the modification process. The AC@CNTs-M had more surface functional groups of hydroxyl and carboxyl, which are favorable for the adsorption of NO 3 −N. The NO 3 −N adsorption on AC@CNTs-M was best defined by the pseudo-second-order model, and the isothermal analysis shows that NO 3 −N adsorption is a multiple process with a maximum adsorption capacity of 27.07 mg•g −1 . All the results demonstrate the great potential of AC@CNTs-M for NO 3 −N adsorption from water, especially in acidic wastewater.

Role of Nitrogenous Functional Group Identity in Accelerating 1,2,3-Trichloropropane Degradation by Pyrogenic Carbonaceous Matter (PCM) and Sulfide Using PCM-like Polymers

“…The addition of 3 mg·L –1 of SRNOM decreased the k obs values for TCP by 18.4 and 3.5% for reactors containing PLP-QA and PLP-py + , respectively, whereas no TCP decay was found without PLP. Our results from the adsorption isotherm (Figure S10) showed higher values of K f for PLP-QA compared to PLP-py + (Table S3), suggesting that PLP-QA has higher adsorption affinity toward SRNOM than PLP-py + . , This could be attributed to the lower content of N functional groups incorporated in PLP-QA (Figure S3), making the surface less hydrophilic and thus accumulating more organic matter. Similar observations were found in previous studies on polymer films. , The larger decrease in TCP decay rates in the presence of PLP-QA in comparison to PLP-py + can be explained by more SRNOM blocking the surface reactive sites of PLP-QA.…”

“…Our results from the adsorption isotherm ( Figure S10 ) showed higher values of K f for PLP-QA compared to PLP-py + ( Table S3 ), suggesting that PLP-QA has higher adsorption affinity toward SRNOM than PLP-py + . 43 , 65 This could be attributed to the lower content of N functional groups incorporated in PLP-QA ( Figure S3 ), making the surface less hydrophilic and thus accumulating more organic matter. Similar observations were found in previous studies on polymer films.…”

Ordered Mesoporous nZVI/Zr-Ce-SBA-15 Catalysts Used for Nitrate Reduction: Synthesis, Optimization and Mechanism

“…Figure 10a shows that the fitting correlation coefficient (R 2 ) of Langmuir and Freundlich isothermal adsorption models of NO 3 -N adsorption on Zr-Ce-SBA-15 composites in simulated wastewater is greater than 0.900, indicating that their models can be better used to describe the adsorption process. A Langmuir adsorption isothermal model assumes that the adsorbent surface is uniform, the adsorption energy is the same everywhere, and the adsorption of the adsorbent to adsorbate belongs to monolayer adsorption [42].…”

“…The smaller the n value is, the greater the adsorption capacity is, and the larger the K F value is, the greater the adsorption capacity is. Meng et al [42] utilized the in situ growth synthesis of a CNTs@AC hybrid material for efficient nitrate-nitrogen adsorption. The isothermal analysis shows that NO 3 -N adsorption is made up of multiple processes with a maximum adsorption capacity of 27.07 mg•g −1 .…”