Adsorption of as(V), Cd(II) and Pb(II), in multicomponent aqueous systems using activated carbons

The project CIMO North-South-South‘‘PROENV2’’, theAdMAtU–project (AKVA Program) financed by the Academy ofFinland, and HYMEPRO financed by the Finnish FundingAgency for Innovation (Tekes) are acknowledged for the financial support. The National University of Tumbes (ProyectoCanon – Resoluci ́on N80722-2014/UNT-R) and the PeruvianNational Council for Science and Technology (CONCYTEC)(Proyecto. No. 002/PE/2012) are gratefully recognized for theirsupport. The authors also want to thank their home universities for their support.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte

Microporous activation carbon made of sawdust from two forestry species for adsorption of methylene blue and heavy metals in aqueous system:case of real polluted water

Abstract Activated carbon samples were prepared and characterized from two novel forestry precursors by one-step chemical activation with ZnCl₂. The adsorption capacities of the adsorbents were tested with methylene blue in monocomponent synthetic solution and with heavy metals from polluted river water. The specific surface areas (S BET ) of the produced activated carbons were 1278 and 1404 m²/g. Further characterization was carried out by FTIR, RAMAN spectroscopy, XRD and FESEM analysis. The pore structure of both activated carbons was predominantly microporous with presence of mesopores. The maximum methylene blue (MB) adsorption capacities for both activated carbons were 250 mg/g and 357 mg/g. MB kinetic experiments were carried out and the influence of the initial MB concentration and the activated carbon dosage was evaluated. The samples reached removal levels close to 100% during the first 5 min of experiments with dissolved As(V) and Pb(II) in the polluted river water, reducing the concentration of these elements until levels below the local water quality standards.Resumen Se prepararon carbones activados a partir de dos precursores de la actividad forestal utilizando activación química en un solo paso con ZnCl₂. Las capacidades de adsorción se determinaron con azul de metileno en soluciones sintéticas y con metales pesados de agua de un río contaminado. Las áreas superficiales específicas de los carbones activados se calcularon entre 1278 y 1404 m²/g. Una caracterización de los materiales se realizó mediante FTIR, espectroscopía RAMAN, difracción de rayos X y microscopía electrónica de barrido. La estructura porosa de ambos carbones activados fue predominantemente microporosa con presencia de mesoporos. La máxima adsorción de azul de metileno por ambos carbones fue de entre 250 mg/g y 357 mg/g. La cinética de adsorción de azul de metileno con diferentes concentraciones iniciales del colorante y diferentes dosis de carbón activado, también fue evaluada. Las muestras alcanzaron una capacidad de remoción de As(V) y Pb(II) disueltos en agua de un río contaminado cercanas 100 % durante los primeros 5 min, reduciendo los valores de estos contaminantes a niveles por debajo de los estándares de calidad de agua locales

A Comparative Study on Activated Carbons Derived from a Broad Range of Agro-industrial Wastes in Removal of Large-Molecular-Size Organic Pollutants in Aqueous Phase

The National University of Tumbes provided important financial support (Proyecto de Investigacion Docente - Resolucion No 1217-2013/UNT-R). The Academy of Sciences of the Czech Republic and Consejo Nacional de Ciencia, Tecnologia e Innovacion Tecnologica (CONCYTEC) in Peru (joint project reg. No. 002/PE/2012) are also gratefully recognized for their support. The Academy of Finland and the Finnish Funding Agency for Innovation (Tekes) are acknowledged for research funding to the AdMatU project from the Development funds and to the HYMEPRO project, respectively. Thanks to Dr. Gladys Ocharan, Alex Diamond, and Hana Snajdaufova (from ICPF) for technical support and Dr. Tomas Strasak (from ICPF) for help with DFT calculations.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte

Zeolitic imidazole Framework-8 (ZIF-8) fibers by gas-phase conversion of electroblown zinc oxide and aluminum doped zinc oxide fibers

Abstract Electroblowing was used to prepare ZnO and aluminum doped zinc oxide (AZO, 1–3 cation-% of Al) fibers. The as-blown fibers were calcined at 500 °C to obtain the target material. The average fiber diameters ranged from 240 ± 60 nm for ZnO fibers to 330 ± 80 nm for AZO with 3% Al. Smaller crystallite size was measured with x-ray diffraction for the Al doped fibers. Electroblowing was found out be an effective method to increase the fiber productivity over electrospinning and other methods reported in literature to prepare AZO fibers as a high production rate of 0.32 g/h was achieved. The ZnO and AZO fibers could be converted to zeolitic imidazole framework-8 [ZIF-8, zinc(2-methylimidazolate)₂] by a solvent free thermal treatment in an autoclave under 2-methylimidazole (HmIM) vapor at 150 and 200 °C while preserving the fibrous structure. The conversion process to ZIF-8 occurred faster at higher temperatures and on fibers with smaller crystallite size. Depending on the conversion treatment time either ZnO/ZIF-8 and AZO/ZIF-8 core/shell fibers or ZIF-8 fibers could be obtained. At best the prepared ZIF-8 fibers had a very high BET specific surface area of 1340 m²/g

Utilization of Volatile Organic Compounds as an Alternative for Destructive Abatement

The treatment of volatile organic compounds (VOC) emissions is a necessity of today. The catalytic treatment has already proven to be environmentally and economically sound technology for the total oxidation of the VOCs. However, in certain cases, it may also become economical to utilize these emissions in some profitable way. Currently, the most common way to utilize the VOC emissions is their use in energy production. However, interesting possibilities are arising from the usage of VOCs in hydrogen and syngas production. Production of chemicals from VOC emissions is still mainly at the research stage. However, few commercial examples exist. This review will summarize the commercially existing VOC utilization possibilities, present the utilization applications that are in the research stage and introduce some novel ideas related to the catalytic utilization possibilities of the VOC emissions. In general, there exist a vast number of possibilities for VOC utilization via different catalytic processes, which creates also a good research potential for the future

Ceramic hydroxyapatite foam as a new material for Bisphenol A removal from contaminated water

Abstract Ceramic hydroxyapatite foam (CF-HAP) was prepared by combining slip-casting and foaming methods. The prepared CF-HAP was characterized by scanning electron microscopy (SEM), physisorption of N2, Fourier transforms infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The results of the specific surface area and SEM analyses revealed that the used shaping method provides CF-HAP with a wide range of porosity including macro and mesopores. Based on FTIR and XRD analyses, the CF-HAP is similar to pure well-crystallized hydroxyapatite. The adsorption results revealed that 94% of the BPA with a concentration of (40 mg/L) was effectively removed from the water and that the maximum adsorption capacity was higher in acidic than in basic medium. The thermodynamic studies indicated that the adsorption reaction was spontaneous and endothermic in nature. The adsorption capacity increased with the temperature and the BPA is chemisorbed on the ceramic foam. The isotherm data fitted slightly better with the Liu than with the Freundlich and Langmuir models suggesting that the adsorption was homogeneous and occurred only in the monolayer. The adsorption process depends largely on the BPA concentration and the results fitted well with the pseudo-first-order model. This confirms that the interaction between the BPA and the CF-HAP was mainly chemical in nature. The FTIR analysis of the used and fresh CF-HAP showed that all the hydroxyl and phosphorus bands characteristic of the hydroxyapatite shifted after adsorption of Bisphenol A. This suggests that the adsorption of Bisphenol A occurred in the sites of the hydroxyapatite. Therefore, it can be concluded that the CF-HAP has the potential to be used as an adsorbent for wastewater treatment and purification processes

Evaluation and selection of biochars and hydrochars derived from agricultural wastes for the use as adsorbent and energy storage materials

The utilization of unconventional agricultural wastes to obtain new porous carbonaceous materials, at mild pyrolysis temperatures and without complex procedures, for either water treatment and energy storage applications is important from the economic and environmental perspective. In this study, biochars and hydrochars were prepared from banana rachis, cocoa pod husks, and rice husks at 600 °C-2 h, under nitrogen flux. The prepared materials were characterized to better understand how their morphological, textural, physical-chemical and/or structural properties correlate with their methylene blue (MB) adsorption capacities. The material with the best properties (mainly SBET > 800 m2/g) and MB adsorption capacity was a novel biochar prepared from banana rachis (BW-BC). This novel material was selected for additional kinetics and equilibrium adsorption tests for lead (Pb) along with its energy storage capacity. In equilibrium test, the novel biochar reached a maximum adsorption capacity for methylene blue of 243.4 mg/g and the highest adsorption capacity for Pb(II) of 179.7 mg/g. In the kinetic adsorption test, the equilibrium adsorption value for methylene blue was 150.4 mg/g and that for Pb(II) was 159.6 mg/g. Most importantly, the performance of the BW-BC material for energy storage in supercapacitors surpassed that of the commercial activated carbon YP50F, reaching specific energy values of 6.66 and 8.52 Wh/kg in acidic and neutral electrolytes, respectively. Among the evaluated hydrochar and biochars derived of agrowastes, the biochar prepared from banana rachis showed the best properties, being potentially useful as adsorbent or as an electrode material for energy storage

Hydrothermal carbonization of Argan nut shell:functional mesoporous carbon with excellent performance in the adsorption of bisphenol A and diuron

Abstract Hydrochar derived from Argan nut shell (ANS) was synthesized and applied to remove bisphenol A (BPA) and diuron. The results indicated that the hydrochar prepared at 200 °C (HTC@ANS-200) possessed a higher specific surface area (42 m²/g) than hydrochar (HTC@ANS-180) prepared at 180 °C (17 m²/g). The hydrochars exhibited spherical particles, which are rich in functional groups. The HTC@ANS-200 exhibited high adsorption efficiency, of about 92% of the BPA removal and 95% of diuron removal. The maximum Langmuir adsorption capacities of HTC@ANS-200 at room temperature were 1162.79 mg/for Bisphenol A and 833.33 mg/g for diuron (higher than most reported adsorbents). The adsorption process was spontaneous (− ΔG°) and exothermic (− ΔH°). Excellent reusability was reclaimed after five cycles, the removal efficiency showed a weak decrease of 4% for BPA and 1% for diuron. The analysis of Fourier transforms infrared spectrometry demonstrated that the aromatic C=C and OH played major roles in the adsorption mechanisms of BPA and diuron in this study. The high adsorption capacity was attributed to the beneficial porosity (The pore size of HTC@ANS-200 bigger than the size of BPA and diuron molecule) and surface functional groups. BPA and diuron adsorption occurred also via multiple adsorption mechanisms, including pore filling, π–π interactions, and hydrogen bonding interactions on HTC@ANS-200

Steam activation of waste biomass:highly microporous carbon, optimization of bisphenol A, and diuron adsorption by response surface methodology

Abstract Highly microporous carbons were prepared from argan nut shell (ANS) using steam activation method. The carbons prepared (ANS@H2O-30, ANS@H2O-90, and ANS@H2O-120) were characterized using X-ray diffraction, scanning electron microscopy, Fourier-transform infrared, nitrogen adsorption, total X-ray fluorescence, and temperature-programmed desorption (TPD). The ANS@H2O-120 was found to have a high surface area of 2853 m²/g. The adsorption of bisphenol A and diuron on ANS@H2O-120 was investigated. The isotherm data were fitted using Langmuir and Freundlich models. Langmuir isotherm model presented the best fit to the experimental data suggesting micropore filling of ANS@H2O-120. The ANS@H2O-120 adsorbent demonstrated high monolayer adsorption capacity of 1408 and 1087 mg/g for bisphenol A and diuron, respectively. The efficiency of the adsorption was linked to the porous structure and to the availability of the surface adsorption sites on ANS@H2O-120. Response surface method was used to optimize the removal efficiency of bisphenol A and diuron on ANS@H2O-120 from aqueous solution