Facile preparation of lotus seedpod-derived magnetic porous carbon for catalytic oxidation of Ponceau 4R

In this research, magnetic porous carbon was directly synthesized through one-step pyrolysis of FeCl3 – lotus seedpod mixture. Properties of the obtained material were analysed by X-ray powder diffraction, SEM image, nitrogen adsorption isotherm and vibrating sample magnetometer. The results showed that magnetic Fe3O4 particles were successfully formed over material template in 1 hour. The magnetic porous carbon possessed the specific magnetization of 7.13 emu/g, high specific surface area of 288 m2/g and total pore volume of 0.18 cm3/g. The material was subsequently applied as a potential catalyst for Ponceau 4R degradation by H2O2. Parameters including pH, H2O2 concentration, and different types of catalysts were investigated. At pH 3, 200 ppm H2O2, and 0.40 g/L magnetic porous carbon, 83% Ponceau 4R 50 ppm was removed after 120 minutes treatment. Moreover, the catalyst powders were separated from the treated mixture easily by a magnet. Summarily, magnetic porous carbon can promise to be an efficient catalyst in decomposition of Ponceau 4R.

Magnesium Aluminate Nanoparticles for Chemical Detoxification of Sarin and Soman

The solutions of Mg(NO3)2, Al(NO3)3, and (NH4)2CO3 were mixed at pH 8 and then heated at 95 °C for 4 h, aged at room temperature for 16 h, and calcined at 650 °C for 4 h to obtain magnesium aluminate nanoparticles. The obtained materials exhibited spinel structure with the particle size being 6 to 26 nm. The nanoparticles demonstrated type IV nitrogen adsorption isotherm, typical of mesoporosity with a surface area of 325 m2/g. They were utilized for studies on chemical detoxification of deadly chemical warfare agents such as sarin and soman. Our results showed that the magnesium aluminate nanoparticles effectively decontaminated more than 99% of sarin and soman within 8–10 min when used at a ratio of 1:50–60% w/w.

Study on Shale Adsorption Equation Based on Monolayer Adsorption, Multilayer Adsorption, and Capillary Condensation

Shale gas is an effective gas resource all over the world. The evaluation of pore structure plays a critical role in exploring shale gas efficiently. Nitrogen adsorption experiment is one of the significant approaches to analyze pore size structure of shale. Shale is extremely heterogeneous due to component diversity and structure complexity. Therefore, adsorption isotherms for homogeneous adsorbents and empirical isotherms may not apply to shale. The shape of adsorption-desorption curve indicates that nitrogen adsorption on shale includes monolayer adsorption, multilayer adsorption, and capillary condensation. Usually, Langmuir isotherm is a monolayer adsorption model for ideal interfaces; BET (Brunauer, Emmett, Teller) adsorption isotherm is a multilayer adsorption model based on specific assumptions; Freundlich isotherm is an empirical equation widely applied in liquid phase adsorption. In this study, a new nitrogen adsorption isotherm is applied to simultaneously depict monolayer adsorption, multilayer adsorption, and capillary condensation, which provides more real and accurate representation of nitrogen adsorption on shale. In addition, parameters are discussed in relation to heat of adsorption which is relevant to the shape of the adsorption isotherm curve. The curve fitting results indicate that our new nitrogen adsorption isotherm can appropriately describe the whole process of nitrogen adsorption on shale.

Synthesis of Fe–Ni–Ce trimetallic catalyst nanoparticles via impregnation and co-precipitation and their application to dye degradation

In this study, trimetallic catalysts were prepared via the co-precipitation and impregnation methods. In order to investigate the effect of impregnation on the catalytic activity and crystallite size, a trimetallic catalyst, Fe–Ni–Ce, was prepared through the co-precipitation method in one set of experiments, and cerium was impregnated with the Ni–Fe mixture in the final stage of the preparation in another set. Fourier transform infrared spectroscopy was employed to confirm the formation of trimetallic catalysts and the success of the impregnation method. The Brunauer–Emmett–Teller nitrogen adsorption isotherm exhibits a high specific surface area (approximately 39 m

Experimental Study on Identification Diffusion Pores, Permeation Pores and Cleats of Coal Samples

Coal pore systems can be commonly classified as diffusion pores, permeation pores and cleats. The classification accuracy influences the coalbed methane (CBM) migration processes from diffusion to permeation and then to outflow, and finally affects the predicted CBM recoverability. To classify coal pore systems precisely, measurements of nuclear magnetic resonance (NMR), mercury intrusion porosimetry (MIP), and nitrogen adsorption isotherm (NAI) are conducted in this paper, and then a comprehensive classification method is proposed. The following cognitions are achieved. NMR spectra can be divided into three categories of three-peak, single narrow peak, and non-three/non-single-narrow peak spectra. The former two categories can be directly used to identify coal pore systems as one peak representing one pore system, and pore systems of the last category can be distinguished by using cumulative amplitudes at the fully water-saturated and centrifuged conditions. Fractal theory suggests that the dividing radii of diffusion–permeation pores obtained by MIP and NAI are quite close, which indicates that the two methods are both effective and accurate. Comparisons between mercury intrusive and cumulative amplitudes indicate that the classification results obtained by measurements of MIP and NMR are similar, which can be a base for transforming transverse relaxation time to pore radius. As a result, the dividing radius of diffusion–permeation pores is about 65 nm, and that of permeation–cleat pores is approximately 600–700 nm.

Optimization of Production Conditions for Activated Carbons from Rice Husk by Potassium Carbonate Using Response Surface Methodology

A three-factor-three-level experiment was developed by the central composite design (CCD) and Response surface methodology to discuss the effects of concentration of K2CO3, activation temperature and time on the adsorption capacity of the activated carbon (AC) derived from the rice husk and to identify the key preparation parameters. The performance of the AC was characterized by nitrogen adsorption isotherm as Brunauer–Emmett–Teller (BET) and scanning electron microscope (SEM), respectively. The optimal parameters were obtained: Rice husk was soaked in K2CO3 solution (2.32 mol/L) with an impregnation ratio (rice husk: K2CO3=1:3) (wt. %), activated at 1239 K for 0.48 h. The results showed that iodine adsorption capacity of the AC was 1268.52 mg/g, the error between the models predicted (1356.98 mg/g) was only 6.2%. The AC has a large apparent surface area (SBET = 1312 m2/g), total pore volume (0.78 cm3/g) and average pore diameter (11.92 Å).

Radiation damages on mesoporous silica thin films and bulk materials

ABSTRACTMesoporous silicas are highly potential materials for applications in the nuclear field like separation, recycling or nuclear wastes confinement. In this work, the effects of the radiation damage on the mesoporous network were investigated by XRR (X-Rays Reflectivity) and nitrogen adsorption isotherm on respectively mesoporous organized thin films (SBA) and disordered bulk mesoporous materials (Vycor glass). The article attempts to answer the question of the existence of a relationship between the rigidity of the mesoporous silica network, and the behavior of silica materials under irradiation.

Adsorption Characteristics of Natural Zeolite on Ammonia Nitrogen

The experiments of ammonia nitrogen adsorption isotherm and adsorption kinetics were conducted with natural zeolite, particle size of 1～1.5 mm and 2～4 mm separately. The results show that adsorption isotherm of zeolite on ammonia nitrogen accorded with Freundlich type. The maximum adsorption of crude zeolite and fine zeolite on ammonia nitrogen are 5.83 (mg /g) and 18.38 (mg /g) respectively, which indicated that absorption effect of fine zeolite is better than crude zeolite. The adsorption process of crude zeolite on ammonia nitrogen is first-order reaction with rate constant of 0.02( g•m－2•h－1).

Research of Pore Structure of Phosphoaluminate Cement Paste Using Nitrogen Adsorption Isotherm

Phosphoaluminate cement (PAC) sets quickly and develops high early strength. As a novel cementitious material, its hydration mechanism and microstructure are more complex than ordinary cement. Based on nitrogen adsorption isotherm method, investigated characteristic of adsorption isotherm of PAC paste, adsorption loop and pore distribution at different hydration period with various W/C ratio, results show that adsorption and desorption isotherm are tight relate to pore structure and pore distribution. In addition, the study analyzed the scope of application of nitrogen adsorption isotherm method on investigating pore structure of cement paste.