Honeycomb-like cork activated carbon with ultra-high adsorption capacity for anionic, cationic and mixed dye: Preparation, performance and mechanism.

Herein, the cork activated carbon (CAC) with excellent adsorption performance for cationic dye, anionic dye, and mixed dye was obtained by a two-step pyrolysis method. The CAC exhibits a fluffy honeycomb structure consisted of porous carbon nanosheets (100-200 nm), ultra-high specific surface area (3402.68 m2/g), and well-developed hierarchical porous structure, which offers a great deal of adsorption sites and transport channels to dye molecules. The adsorption process of all the dyes onto CAC is better described by Langmuir isotherm model and pseudo-2nd-order kinetic model. The CAC shows ultra-high adsorption capacity for methylene blue (1283.99 mg/g), rhodamine B (4067.57 mg/g), methyl orange (2666.2 mg/g), and congo red (8920.61 mg/g), with an extremely low equilibrium adsorption time (∼10 min). Collectively, this study demonstrated the potential of converting waste cork into high value-added adsorbent for the efficient purification of dye wastewater.

Honeycomb-like activated carbon with microporous nanosheets structure prepared from waste biomass cork for highly efficient dye wastewater treatment.

Cork, a porous biomass material, is consist of thin-walled hollow prismatic cells arranged into a compact and orderly honeycomb-like structure and could be applied as an adsorption material. Here, cork-activated carbons (CACs) with a fluffy honeycomb-like structure were synthesized by two-step pyrolysis with solid KOH chemical activation to rapidly and efficiently adsorb methylene blue (MB) (maximum wavelength: 664 nm). The structure, morphology and surface functional groups of the CACs were characterized using BET, SEM, and FTIR analysis. The results show that the CACs have a well-developed hierarchical porous structure and an ultra-high specific surface area of 2864.9 m2/g, which would facilitate the efficient diffusion and adsorption of MB molecules onto CACs. MB adsorption performance results show that the CACs have an outstanding maximum MB adsorption capacity (1103.68 mg/g) and fast adsorption kinetics (800 mg/L, 99.8% in 10 min), indicating that CACs possess significant advantages compared with most other adsorbents previously reported. The adsorption mechanism was studied by various kinetic models, isothermal models and thermodynamic models. Langmuir model is the most adapted to describe the adsorption process, indicating that the MB molecules are uniformly adsorbed on CAC's surface in a single layer. Moreover, MB adsorption by the CACs was an endothermic, spontaneous and randomly increasing adsorption. The regeneration test showed that the uptake of MB onto CACs can still reached 580 mg/g after three adsorption-desorption cycles, demonstrating the excellent reusability of CACs. The continuous adsorption performance of MB onto CACs was evaluated by a packed column test, which further confirmed its potential as an adsorbent for dye wastewater purification.

[Epidemiological survey of asthma among children aged 0-14 years in 2010 in urban Zhongshan, China].

OBJECTIVE: To investigate the prevalence, current treatment, and clinical characteristics of asthma, as well as the risk factors for this disease, among children aged 0-14 years in 2010 in urban Zhongshan, China. METHODS: A total of 10 336 children aged 0-14 years were selected from urban Zhongshan by cluster random sampling. The Third National Childhood Asthma Epidemiological Questionnaire 2010 was used to analyze the prevalence, current treatment, and clinical characteristics of childhood asthma, as well as the risk factors for this disease. RESULTS: Asthma was diagnosed in 179 cases (1.73%). The prevalence of asthma in male children was significantly higher than that in female children (2.25% vs 1.16%; P<0.01). Of the 179 patients, severe attacks were common in 104 cases (58.1%), 110 cases (61.5%) had slow onset, 102 cases (57.0%) had gradually relieved conditions, 61 cases (34.1%) suffered from asthma during seasonal transition, and 150 cases (83.8%) developed asthma due to respiratory tract infection. Among all asthmatic children, 71.5% had been treated with inhaled corticosteroids, and 71.5% had been treated with bronchodilator. The multivariate logistic regression analysis showed that a history of penicillin allergy, a family history of allergy, food allergy, eczema, allergic rhinitis, cesarean delivery, family mould, and perinatal passive smoking were independent risk factors for childhood asthma. CONCLUSIONS: The prevalence of childhood asthma in urban Zhongshan is on a high level, and is associated with gender. The treatment of asthma has been standardized, but still needs further improvement. The onset of asthma attack is influenced by various factors.

[Incidence of wheezing and chronic cough in children aged 3-14 years in rural and urban areas of Zhongshan, China: a questionnaire survey].

OBJECTIVE: To investigate the incidence of wheezing and chronic cough in children aged 3-14 years in different living areas of Zhongshan, China. METHODS: According to the unified program of the 2010 national epidemiological survey of asthmatic children aged 0-14 years, a questionnaire survey of the children aged 3-14 years in rural and urban areas of Zhongshan was conducted. RESULTS: A total of 15 763 children were included in the survey. Among all participants, 8 248 were from the urban area, and 7 515 from the rual area; 8 306 were boys, and 7 457 were girls. The percentage of children with a history of wheezing was significantly higher in the urban group than in the rural group (6.6% vs 3.2%; P<0.05), and it was significantly higher in boys than in girls for each group (P<0.05). The urban group had a significantly higher percentage of individuals who had wheezing in the past one year than the rural group (2.8% vs 1.5%; P<0.05), and this percentage was significantly higher in boys than in girls for each group (P<0.05). Compared with the rural group, the urban group had a significantly higher percentage of individuals who had chronic cough (duration 1 year) (7.9% vs 3.1%; P<0.05). The above indices were relatively high in children under 6 years of age, and all but the percentage of girls who had wheezing in the past one year in both rural and urban areas showed significant differences between all age groups. CONCLUSIONS: The incidence of wheezing and chronic cough varies with age, sex, and living area for children aged 3-14 years in Zhongshan, and it is relatively high under 6 years of age, in the urban area, and among boys.