Search

Water pollution caused by dyes is a pressing environmental challenge due to their persistence and difficulty in degradation. Herein, an anionic adsorbent (HS-PAANa) was synthesized by grafting polyacrylic acid (PAA) onto the agricultural waste-hemp stem (HS). The obtained HS-PAANa adsorbent exhibited rapid adsorption kinetics, high adsorption capacity, and a favorable preference for cationic dyes, such as methylene blue (MB) and crystal violet (CV). The experimental data fit well with the pseudo-second-order kinetic model and Langmuir isotherm, demonstrating the efficiency of HS-PAANa in dye removal. Notably, the optimal adsorption capacities of HS-PAANa for MB and CV were found to be 1296.65 mg/g and 1451.43 mg/g, respectively. In the cationic/anionic dyes (MB/MO) binary systems, HS-PAANa exhibited enhanced selective adsorption of cationic dyes (MB), indicating its potential for targeted removal of specific dyes from mixed solutions. Moreover, HS-PAANa adsorption shows an excellent recyclability, after five cycles, HS-PAANa still maintained MB and CV removal rates of 93.85% and 95.08%, respectively. Therefore, the bioadsorbent HS-PAANa exhibits high potential as a highly efficient adsorbent for the effective treatment of cationic pollutants in wastewater. [ABSTRACT FROM AUTHOR]

The efficient capture of nuclear waste such as radionuclide iodine has received more worldwide attention because of the effects of radiation on biological health. Adsorption is considered to be an efficient, low-cost, and environmentally friendly method for iodine removal. Recently, a new kind of phosphine-based covalent organic frameworks (P-COFs) with flexible and nonplanar structure have attracted great attention because of their high specific surface area and good thermal stability. The existence of electron-rich heteroatoms (P, N) as well as the large π-conjugated network structure may be beneficial to the absorption of iodine. In this study, a biphenyl linked P-COF was synthesized for the capture of iodine. It shows a uniform microsphere structure with a diameter of about 1.2 μm, a large BET surface area up to 1056 m2 g−1, and a high thermal stability (up to 500 °C). This P-COF exhibits rapid and exceptional iodine uptake in both volatile iodine and iodine/cyclohexane solution with adsorption capacities of 6.19 g g−1 and 1.30 g g−1, respectively, suggesting that P-COF may be a potential candidate for radioiodine capture from nuclear waste. [Display omitted] • A phosphine-based covalent organic framework (P-COF) is developed for the capture of iodine. • P-COF exhibits rapid volatile iodine uptake with an adsorption capacity of 5.00 g g−1 within 2 h. • The equilibrium adsorption capacity of vapor iodine reaches as high as 6.19 g g−1. • P-COF shows tremendous iodine adsorption with capacity of 1.30 g g−1 in cyclohexane solution. [ABSTRACT FROM AUTHOR]

Nuclear waste such as radioactive iodine has been received worldwide attention because of the effects of radiation on biological health. The efficient capture of radioactive iodine is of great importance for the safe utilization of nuclear energy. In this study, a functional porous organic polymer (P-TzTz) with high sulfur and nitrogen contents was synthesized by the catalyst-free hydrothermal process of dithiocarbanate (DTO) and benzo[1,2-b:3,4-b′:5,6-b″]trithiophene-2,5,8-tricarbaldehyde (BTT-THO) in N , N -dimethylformamide under N 2 atmosphere. This tailor-made amorphous polymer exhibits high affinity and adsorption capacity for iodine owing to its effective electron-rich sorption sites, π-conjugated structure and hierarchically porous structure. P-TzTz displays an excellent reversible iodine uptake with capacity of 326 wt% for volatile iodine. After five cycles of volatile iodine adsorption, P-TzTz almost retains the same adsorption capacity with the original adsorbent. In addition, P-TzTz also exhibits excellent adsorptive performance for the removal of iodine from iodine/cyclohexane solution with an adsorption capacity of 494.09 mg g−1, suggesting that P-TzTz may be also an effective adsorbent for the removal of iodine from solution. Image 1 • A functional porous organic polymer with rich S and N (P-TzTz) was synthesized. • P-TzTz shows excellent volatile iodine uptake of 326 wt%. • P-TzTz can adsorb iodine in cyclohexane solution with an excellent adsorption capacity of 494.09 mg g−1. • After five cycles, P-TzTz shows almost the same iodine adsorption capacity with pristine. [ABSTRACT FROM AUTHOR]

Organic dye containing wastewater and nuclear waste have received more worldwide attention because of the significant environmental problems and the effects of radiation on health. Adsorption is considered to be an efficient, low-cost, and environmentally friendly method for pollutant removal. In this paper, we developed a novel covalent organic framework (BTT-TAPT-COF) adsorbent which contains abundant S and N active sites as well as extended π-conjugated structure. This COF shows high crystallinity, large surface area, and thermal stability. Due to the porous feature, existence of electron-rich heteroatoms as well as the large π-conjugated network structure, BTT-TAPT-COF exhibits excellent adsorptive performance for the removal of hazardous dye indigo carmine with an adsorption capacity of 547.33 mg g−1 and rapid reversible volatile iodine uptake with an adsorption capacity of 276 wt%. After five cycles, BTT-TAPT-COF almost retains the same iodine adsorption capacity with the original adsorbent. Image 1 • N- and S-rich covalent organic framework (BTT-TAPT-COF) was synthesized. • The BTT-TAPT-COF absorbs hazardous dye indigo carmine with an excellent adsorption capacity of 547.33 mg g−1. • BTT-TAPT-COF shows the iodine uptake of 276 wt%. • BTT-TAPT-COF retains almost the same iodine adsorption capacity with the original adsorbent. [ABSTRACT FROM AUTHOR]