[en] Will the CO₂ capture be affected by the N-doping? This question remains conflict due to the effect of oxygen content in N-doped porous carbons on CO₂ uptake has not been systematically investigated. Herein, the effects of N-free and N-doped porous carbons on CO₂ uptake were investigated by experiments and theoretical calculations. To elucidate the relative influences of nitrogen functional groups, we synthesized a series of carbons without or with N-doping (2.73–9.44% N) by varying the synthesis conditions. Experimental results show that the introduction of oxygen and nitrogen into carbon framework improves CO₂ capture in porous carbons (PCs) and N-doped porous carbons (NPCs). Among these samples, the NPC600 exhibits an exceptionally high CO₂ adsorption capacity (5.01 mmol g⁻¹ at 1 bar and 25 °C). Based on the theoretical calculations, the introduction of nitrogen into carbon framework with high oxygen content further enhances electrostatic interaction for CO₂ adsorption. Moreover, the doping of nitrogen to carbon framework also has a greater effect on both the selectivity for CO₂/N₂ and the isosteric heat of CO₂ adsorption. It is predicted that this investigation will eliminate any ambiguities and better explain the influence of N-doping on CO₂ capture.

[en] Objective: To observe the incidence, the curative rate and the long term prognosis of congenital hypothyroidism (CH) newborns detected by screening program in Tianjin area initiated at the beginning of 1982. Methods: Primarily, the T₄ and thyroid-stimulating hormone (TSH) radioimmunoassay (RIA) of dried blood sample on filter paper developed in our laboratory were used. The TSH RIA was replaced by a time-resolved fluorescence immunoassay (Tr-FIA) in 1998. The primary T₄ RIA was replaced by a commercial kit for T₄ RIA in 1999. SPECT imaging on thyroid was performed after intravenous administration of ⁹⁹Tc^mO₄^- 11.1-18.5 MBq. Results: A total of 266 401 neonates was screened for CH in our laboratory in Tianjin area. 36 cases of permanent CH were confirmed in the program. The incidence of CH was 0.014%; 22 cases of CH here were kept in treatment . Of the 22 cases, 19 cases were recalled in 2000, 18 of them (94.7%) showed currently with normal growth and development in the check-up. Imaging on thyroid (⁹⁹Tc^m): among 19 patients with CH, 1 case was found with normal gland, 1 with a hypogenetic thyroid, 3 cases with enlarged thyroid, 7 with ectopic gland, and the remaining 7 cases didn't show any image of thyroid. The bone age of 20 CH children was evaluated with the X ray radiography. In 6 cases of them, the bone age was normal, and 7 cases had progressed from development delay to normal. So far, retarded bone age of the remaining 7 CH patients didn't show any renewing yet. The bone age renewal was found in 3 younger children of them, but for the other 3 cases (9-12 years old) of CH patients with thyroid gland absence, the renewal of bone age was slower. Intelligence quotient (IQ) in 16 cases was measured. The scores of IQ in 13 cases of them (81.3%) were 80-119, 2 cases 72-77, 1 case 60. IQs of 6/16 cases of CH patients with thyroid absence were lower. May be it related to that, their hypothyroidism during fetal life was severer. Conclusions: Neonatal screening is an effective measure to cope with congenital hypothyroidism. If authors can do fetal hypothyroidism screening that would be even helpful

[en] Highlights: • Four nanoporous carbons were prepared from MOF-5 template and additional carbon source by carbonization at different temperatures (600–900 °C). • The as-obtained sample MUC900 exhibits the highest surface areas (2307 m² g⁻¹) and pore volumes (2.54 ml g⁻¹). • By changing the carbonization temperature it can finely tune the pore volume of the MUCT, which having a uniform pore size of around 4.0 nm. • The detailed interaction mechanism between functional groups and CO₂ molecules is elucidated. Four nanoporous carbons (MUCT) were prepared from metal-organic framework (MOF-5) template and additional carbon source (i.e. urea) by carbonization at different temperatures (600–900 °C). The results showed that specific surface area of four samples was obtained in the range from 1030 to 2307 m² g^-1. By changing the carbonization temperature it can finely tune the pore volume of the MUCT, which having a uniform pore size of around 4.0 nm. With an increasing carbonization temperature, the micropore surface area of MUCT samples varied slightly, but mesopore surface area increased obviously, which had little influence on carbon dioxide (CO₂) adsorption capacity. The as-obtained sample MUC900 exhibited the superior CO₂ capture capacity of 3.7 mmol g^-1 at 0 °C (1 atm). First principle calculations were conducted on carbon models with various functional groups to distinguish heterogeneity and understand carbon surface chemistry for CO₂ adsorption. The interaction between CO₂ and N-containing functional groups is mainly weak Lewis acid-base interaction. On the other hand, the pyrrole and amine groups show exceptional hydrogen-bonding interaction. The hydroxyls promote the interaction between carbon dioxide and functional groups through hydrogen-bonding interactions and electrostatic potentials, thereby increasing CO₂ capture of MUCT.

[en] The pyrolysis of tobacco stem (TS), a potential source of lignocellulosic biomass, is investigated, focusing on gas formation via thermogravimetric analysis–mass spectrometry to obtain accurate gaseous product distributions under various conditions. The results revealed that the majority of the gaseous products were formed under 900 K with a shoulder pyrolysis region (600–800 K) as the main source of gas formation, where the formation curve of CO₂ was used to track the pyrolysis of hemicellulose, cellulose, and lignin. The formation of four aromatics from lignin occurred over the range of 500–900 K, roughly in the sequence of phenol, toluene, xylene, and benzene. Furthermore, the demineralization of TS with HCl did not lead to optimal results, with increased phenol and decreased syngas production, whereas pretreatment with NaOH for hydrolysis was found to significantly increase methane production and decrease the amount of aromatics formed, suggesting that this method should lead to superior results and a simpler reaction mechanism.

[en] Acetone, one of the most common VOCs, could cause serious air pollution and threat the human health when someone is exposed to certain concentration of acetone. Thereof, acetone detection and elimination in the air was significant to prohibit the hazard of acetone. Acetone adsorbed to (BeO)₁₂, (MgO)₁₂ and (ZnO)₁₂ nanoparticles and their graphene composites was detailed studied by density functional theory. The adsorption energy of acetone to (MO)₁₂ (M = Be, Mg, Zn) nanoparticles and their graphene composites were high, which means that all the adsorbents are eligible for acetone adsorption. The variation of band gap was utilized to describe the sensibility to acetone. It was found that the (ZnO)₁₂ nanoparticle and its graphene composite were not sensitive to the acetone, while the (BeO)₁₂ and (MgO)₁₂, as well as their graphene composites, were sensitive to acetone. Among the (BeO)₁₂-graphene and (MgO)₁₂-graphene, the latter exhibits more sensitive than the former. The conventional transition state theory was been took to estimate the recovery time. According to our calculation, (BeO)₁₂ and (ZnO)₁₂ nanoparticles and all (MO)₁₂ graphene composites have too long recovery time for the high adsorption energy hampering the recovery of the adsorbents. Contrastingly, (MgO)₁₂ nanoparticle is sensitive to acetone and has receivable recovery time. Therefore, (BeO)₁₂, (MgO)₁₂ and (ZnO)₁₂ nanoparticles and their graphene composites may be potential adsorbents for acetone adsorption for their relatively high adsorption energy. The (MgO)₁₂ nanoparticle could be an excellent gas sensor for detecting acetone due to the sensitivity acetone and receivable recovery time.

[en] The relative influence of porous structure and functional groups of porous carbon materials for acetone adsorption is presented in this article. Here, we have successfully prepared oxygen and nitrogen doping porous carbons (ONPCs) by a hydrothermal method using waste tobacco stem as the carbon precursor and ethylenediamine as a nitrogen source. The resulting ONPCs have high specific surface (906–2940 m² g⁻¹) and chemical compositions (1.80–5.22% N and 5.81–11.77% O). This carbon shows high acetone adsorption capacity (i.e., 16.91 mmol g⁻¹ at 25 °C and 18 kPa). The pore volume and specific surface area of ONPCs were found to be determinative factors for acetone adsorption at high pressure, and the introduction of oxygen and nitrogen into carbon surface can improve acetone adsorption at low pressure. Molecular simulations results suggest that adsorption capacity of acetone is improved at low pressure after doping of oxygen and nitrogen functional groups, but equilibrium adsorption capacity is unchanged. This is in good agreement with the experimental results that these functional groups are primarily responsible for the materials’ low-pressure acetone adsorption capacity. This work provides insights into material design and further development for acetone adsorption.

[en] Graphical abstract: The role of nitrogen species in increasing CO_2 adsorption capacity has been explained with the mechanisms of base–acid interaction, as well as hydrogen bonds interaction. - Highlights: • A porous carbon (ZC) was prepared at 900 °C using ZIF-8 as a solid template for CO_2 adsorption. • The ZC was further treated by ammonia functionalization to improve CO_2 uptake. • The detailed interaction mechanism between N-containing groups and CO_2 molecules is elucidated. - Abstract: A porous carbon (ZC) was prepared at 900 °C using zeolitic imidazolate framework-8 (ZIF-8) as a solid template for CO_2 adsorption. The ZC was further treated by ammonia functionalization to improve CO_2 uptake. The textural and surface characteristics of ZC samples were determined by X-ray diffraction (XRD), N_2 adsorption, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). It was revealed that ammonia treatment at 600 °C considerably enhanced the specific surface area and N-content of ZC. However, the pyrrolic-N group was decreased, yet the pyridinic-N group was increased with an increased temperature. The pyrrolic-N significantly enhanced CO_2 adsorption. The ammonia treatment, on the one hand, increases the alkalinity of ZC sample and the base–acid interaction between N-containing functional groups with CO_2. On the other hand, the ammonia treatment increased pyrrolic-N group (NH) into carbon surface facilitating the hydrogen-bonding interactions between proton of pyrrolic-N and CO_2 molecules.