scholarly journals Adsorption of Ammonium Nitrogen from Aqueous Solution on Chemically Activated Biochar Prepared from Sorghum Distillers Grain

2019 ◽  
Vol 9 (23) ◽  
pp. 5249 ◽  
Author(s):  
Derlin Hsu ◽  
Changyi Lu ◽  
Tairan Pang ◽  
Yuanpeng Wang ◽  
Guanhua Wang

Chemically activated biochars prepared from sorghum distillers grain using two base activators (NaOH and KOH) were investigated for their adsorption properties with respect to ammonium nitrogen from aqueous solution. Detailed characterizations, including scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetry (TG), and specific surface area analyses, were carried out to offer a broad evaluation of the prepared biochars. The results showed that the NaOH- and KOH-activated biochars exhibited significantly enhanced adsorption capacity, by 2.93 and 4.74 times, respectively, in comparison with the pristine biochar. Although the NaOH-activated biochar possessed larger specific surface area (132.8 and 117.7 m2/g for the NaOH- and KOH-activated biochars, respectively), the KOH-activated biochar had higher adsorption capacity owing to its much higher content of functional groups. The adsorption kinetics and isotherms of the KOH-activated biochar at different temperatures were further studied. The biochar had a maximum adsorption capacity of 14.34 mg/g at 45 °C, which was satisfactory compared with other biochars prepared using different feedstocks. The adsorption process followed pseudo-second-order kinetics, and chemical adsorption was the rate-controlling step. The equilibrium data were consistent with the Freundlich isotherm, and the thermodynamic parameters suggested that the adsorption process was endothermic and spontaneous. Consequently, this work demonstrates that chemically activated biochar from sorghum distillers grain is effective for ammonium nitrogen removal.

RSC Advances ◽  
2016 ◽  
Vol 6 (53) ◽  
pp. 47530-47535 ◽  
Author(s):  
Long Pan ◽  
Meng-Ying Xu ◽  
Zi-Lu Liu ◽  
Bi-Bai Du ◽  
Kun-Hao Yang ◽  
...  

A novel type of porous magnetic microsphere (Fe3O4@HCP) was firstly synthesized and possesses a high Brunauer–Emmett–Teller specific surface area and excellent adsorption capacity for organic dyes.


2020 ◽  
Vol 42 (5) ◽  
pp. 728-728
Author(s):  
Aleksandra Micic Aleksandra Micic ◽  
Dragan Djordjevic Dragan Djordjevic ◽  
Ivona Jankovic Castvan Ivona Jankovic Castvan ◽  
Nenad Cirkovic Nenad Cirkovic ◽  
Bratislav Todorovic Bratislav Todorovic

The paper investigates the possibility of removing acid dye from the aqueous solution by an adsorption process on new adsorbent prepared from waste cotton textile from the ready-made garment industry. It is a waste generated during the cutting of the layers of cotton knitwear, which is practically the product from the textile cutting process. The obtained adsorbent is a bulk material with heterogeneous porous particles, of ragged shapes. In particle interiors, there are pronounced cracks, cavities and channels that form the basis of microporous material. The qualitative and quantitative characterization of the obtained adsorbent shows that this is a relatively porous material where the carbon is dominant in the chemical composition. The results of textural properties of new adsorbent from cotton knitwear waste show different parameters which with their numerous values characterize the specific surface area, pore volume or pore diameter. It can be said that the obtained new adsorbent has micropores and small mesopores, which produce a high specific surface area. During adsorption, the longer contact time causes a greater amount of dye on the adsorbent, i.e. with the duration of the adsorption process the dye concentration in the solution decreases. A number of isotherms of two- (Langmuir, Freundlich and Jovanovic), three- (Toth, Sips and Radke-Prausnitz), and four-parameter models (Fritz-Schlunder and Marczewski-Jaroniec) were used to describe the adsorption process. The four-parameter isotherms are best covered by experimental points and most accurately describe the events of adsorption of acid dye on the surface and in the interior of the new adsorbent particles obtained from ready–made garment cotton waste. The results of this research suggest the possibility of practical application in the decolorization of the colored waste waters of the textile industry providing a contribution to protecting the environment from both an economic and a practical point of view.


RSC Advances ◽  
2018 ◽  
Vol 8 (37) ◽  
pp. 21012-21019 ◽  
Author(s):  
Ling Zhu ◽  
Nan Zhao ◽  
Lihong Tong ◽  
Yizhong Lv

The structure activation of K2CO3 enriches the surface pores of biochar and increases the specific surface area nearly 10 times. The changes of pore structure and surface properties significantly affect the adsorption process of naphthalene.


2017 ◽  
Vol 68 (3) ◽  
pp. 483-486
Author(s):  
Constantin Sorin Ion ◽  
Mihaela Bombos ◽  
Gabriel Vasilievici ◽  
Dorin Bombos

Desulfurisation of atmospheric distillation gasoline and gas oil was performed by adsorption process on Fe/ bentonite. The adsorbent was characterized by determining the adsorption isotherms, specific surface area, pore volume and average pore diameter. Adsorption experiments of atmospheric distillation gasoline and gas oil were performed in continuous system at 280�320oC, 5 atm and volume hourly space velocities of 1�2 h-1. The efficiency of adsorption on Fe / bentonite was better at desulphurisation of gasoline versus gas oil.


2021 ◽  
Vol 15 (2) ◽  
pp. 131-144
Author(s):  
Chunjiang Jin ◽  
Huimin Chen ◽  
Luyuan Wang ◽  
Xingxing Cheng ◽  
Donghai An ◽  
...  

In this study, aspen wood sawdust was used as the raw material, and Fe(NO3)3 and CO2 were used as activators. Activated carbon powder (ACP) was produced by the one-step physicochemical activation method in an open vacuum tube furnace. The effects of different mass ratios of Fe(NO3)3 and aspen wood sawdust on the pore structure of ACP were examined under single-variable experimental conditions. The mass ratio was 0–0.4. The detailed characteristics of ACP were examined by nitrogen adsorption, scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. The adsorption capacity of ACP was established by simulating volatile organic compounds (VOCs) using ethyl acetate. The results showed that ACP has a good nanostructure with a large pore volume, specific surface area, and surface functional groups. The pore volume and specific surface area of Fe-AC-0.3 were 0.26 cm3/g and 455.36 m2/g, respectively. The activator played an important role in the formation of the pore structure and morphology of ACP. When the mass ratio was 0–0.3, the porosity increased linearly, but when it was higher than 0.3, the porosity decreased. For example, the pore volume and specific surface area of Fe-AC-0.4 reached 0.24 cm3/g and 430.87 m2/g, respectively. ACP presented good VOC adsorption performance. The Fe-AC-0.3 sample, which contained the most micropore structures, presented the best adsorption capacity for ethyl acetate at 712.58 mg/g. Under the action of the specific reaction products nitrogen dioxide (NO2) and oxygen, the surface of modified ACP samples showed different rich C/O/N surface functional groups, including C-H, C=C, C=O, C-O-C, and C-N.


Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2362 ◽  
Author(s):  
Qinya Fan ◽  
Liqiang Cui ◽  
Guixiang Quan ◽  
Sanfei Wang ◽  
Jianxiong Sun ◽  
...  

Biochar has been studied for remediation of heavy metal-contaminated soils by many researchers. When in external conditions, biochar in soils ages, which can transform its structural properties and adsorption capacity. This study was conducted with two oxidation processes, HNO3/H2SO4 and NaOH/H2O2, to simulate the effects of biochar in acid and alkaline soil conditions. The results show that the oxygen-containing functional groups increased in aged biochar, which led to improve the ratio of oxygen and carbon (O/C). Nitro functional groups were found in the acid-oxidation treated biochar. Destroyed ditches and scars were observed on the surface of aged biochar and resulted in growth in their specific surface area and porosity. Specific surface area increased by 21.1%, 164.9%, and 63.0% for reed-derived biochar treated with water washing, acid oxidation, and basic oxidation, respectively. Greater peaks in the Fourier Transform Infrared Spectroscopy (FTIR) results were found in C–O and O–H on the surface of field-aged biochar. Meanwhile, mappings of energy-dispersive spectroscopy showed that biochar aged in soil was abundant in minerals such as silicon, iron, aluminum, and magnesium. In summary, biochar subjected to wet oxidation aging had an increased capacity to immobilize Cd compared to unaged biochar, and the adsorption capacity of oxidized biochar increased by 28.4% and 13.15% compared to unaged biochar due to improvements in porosity and an increase in functional groups.


2020 ◽  
Vol 850 ◽  
pp. 16-21
Author(s):  
Hoc Thang Nguyen ◽  
Phong Thanh Dang

Diatomite or diatomaceous earth (DE) is one of materials which can be used as an adsorbent to treat heavy metal ions from waste water, even there are many factories used it to clean the water for drinking. However, natural DE (raw DE) has very low adsorption capacity because of low specific surface area. In this work, natural DE from Lam Dong province, Viet Nam was demagnetized to remove iron and activated by HCl solution for 90 minutes with concentration of 10% at room condition. Adsorbent capacity was evaluated using As solution and the results show that the activated diatomite has adsorption capacity three times higher than that of raw DE, and the specific surface area of activated diatomite was increased 47.5% with the main chemical composition of 90.8% SiO2 and high porosity


Fibers ◽  
2019 ◽  
Vol 7 (10) ◽  
pp. 81 ◽  
Author(s):  
Reyna Ojeda-López ◽  
J. Marcos Esparza-Schulz ◽  
Isaac J. Pérez-Hermosillo ◽  
Armin Hernández-Gordillo ◽  
Armando Domínguez-Ortiz

Carbon microfibers (CMF) has been used as an adsorbent material for CO2 and CH4 capture. The gas adsorption capacity depends on the chemical and morphological structure of CMF. The CMF physicochemical properties change according to the applied stabilization and carbonization temperatures. With the aim of studying the effect of stabilization temperature on the structural properties of the carbon microfibers and their CO2 and CH4 adsorption capacity, four different stabilization temperatures (250, 270, 280, and 300 °C) were explored, maintaining a constant carbonization temperature (900 °C). In materials stabilized at 250 and 270 °C, the cyclization was incomplete, in that, the nitrile groups (triple-bond structure, e.g., C≡N) were not converted to a double-bond structure (e.g., C=N), to form a six-membered cyclic pyridine ring, as a consequence the material stabilized at 300 °C resulting in fragile microfibers; therefore, the most appropriate stabilization temperature was 280 °C. Finally, to corroborate that the specific surface area (microporosity) is not the determining factor that influences the adsorption capacity of the materials, carbonization of polyacrylonitrile microfibers (PANMFs) at five different temperatures (600, 700, 800, 900, and 1000 °C) is carried, maintaining a constant temperature of 280 °C for the stabilization process. As a result, the CMF chemical composition directly affects the CO2 and CH4 adsorption capacity, even more directly than the specific surface area. Thus, the chemical variety can be useful to develop carbon microfibers with a high adsorption capacity and selectivity in materials with a low specific surface area. The amount adsorbed at 25 °C and 1.0 bar oscillate between 2.0 and 2.9 mmol/g adsorbent for CO2 and between 0.8 and 2.0 mmol/g adsorbent for CH4, depending on the calcination treatment applicated; these values are comparable with other material adsorbents of greenhouse gases.


2020 ◽  
Vol 7 (8) ◽  
pp. 200079
Author(s):  
Yanlong Li ◽  
Hongxi Li ◽  
Rundong Li ◽  
Xin Su ◽  
Shengqiang Shen

Boron nitride, also known as white graphene, has attracted extensive attention in the fields of adsorption, catalysis and hydrogen storage due to its excellent chemical properties. In this study, a phosphorus-doped boron nitride (P-BN) material was successfully prepared using red phosphorus as a dopant for the preparation of porous boron nitride precursors. The phosphorus content in the P-BN was adjusted based on the addition rate of phosphorus. The specific surface area of P-BN first increased and then decreased with increasing addition rate of phosphorus. The maximum specific surface area was 837.8 m 2 g −1 when the phosphorus addition rate was 0.50. The P-BN prepared in the experiments was used as an adsorbent, and its adsorption capacity for heavy metals from flue gas was investigated. In particular, P-BN presented a stronger adsorption selectivity for zinc compared with other heavy metals, and its adsorption capacity for zinc was 5–38 times higher than for other heavy metals. The maximum adsorption capacity of P-BN for zinc and copper in a single heavy metal atmosphere was 69.45 and 53.80 mg g −1 , respectively.


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