scholarly journals Preparation Process of Straw-based Activated Carbon for Uranium Wastewater Treatment

2020 ◽  
Vol 185 ◽  
pp. 04057
Author(s):  
Hongtao Wang ◽  
Rong Gui ◽  
Wenxia Zhu ◽  
Hankun lu ◽  
Wenze Geng ◽  
...  

A process and equipment for preparing activated carbon from straw and its application in treating uranium wastewater are proposed. The ZnCl2-microwave carbonization method is adopted, which flexibly applies the wave absorbing ability of zinc element and greatly reduces the carbonization time. At the same time, the dehydrogenation of ZnCl2 limits the formation of coal tar and improves the carbon formation rate. Through citric acid modification, a functional group with specific adsorbability to uranyl ions is formed, which can produce high-efficiency complexation effect with uranyl ions and improve the adsorption capacity of uranyl ions. When the wastewater is mixed with other heavy metal elements, uranyl ions occupy the main adsorption sites, which can still maintain excellent targeted adsorption effect and can be targeted to treat uranyl ions in radioactive uranium wastewater. The key equipment in the process consists of cleaning and impurity removal components, raw material crushing components and carbonization components. The whole production process is completed in the same equipment. The optimum adsorption capacity (Ac) of 4.98 mg/g and uranium adsorption rate (Ar) of 99% were obtained by using soybean straw as raw material under the preparation conditions of 20% ZnCl2 solution and 15% citric acid solution.

Molecules ◽  
2020 ◽  
Vol 25 (13) ◽  
pp. 3081 ◽  
Author(s):  
Nurul Aida Nordin ◽  
Norizah Abdul Rahman ◽  
Abdul Halim Abdullah

Heavy metal pollution, such as lead, can cause contamination of water resources and harm human life. Many techniques have been explored and utilized to overcome this problem, with adsorption technology being the most common strategies for water treatment. In this study, carbon nanofibers, polyacrylonitrile (PAN)/sago lignin (SL) carbon nanofibers (PAN/SL CNF) and PAN/SL activated carbon nanofibers (PAN/SL ACNF), with a diameter approximately 300 nm, were produced by electrospinning blends of polyacrylonitrile and sago lignin followed by thermal and acid treatments and used as adsorbents for the removal of Pb(II) ions from aqueous solutions. The incorporation of biodegradable and renewable SL in PAN/SL blends fibers produces the CNF with a smaller diameter than PAN only but preserves the structure of CNF. The adsorption of Pb(II) ions on PAN/SL ACNF was three times higher than that of PAN/SL CNF. The enhanced removal was due to the nitric acid treatment that resulted in the formation of surface oxygenated functional groups that promoted the Pb(II) ions adsorption. The best-suited adsorption conditions that gave the highest percentage removal of 67%, with an adsorption capacity of 524 mg/g, were 40 mg of adsorbent dosage, 125 ppm of Pb(II) solution, pH 5, and a contact time of 240 min. The adsorption data fitted the Langmuir isotherm and the pseudo-second-order kinetic models, indicating that the adsorption is a monolayer, and is governed by the availability of the adsorption sites. With the adsorption capacity of 588 mg/g, determined via the Langmuir isotherm model, the study demonstrated the potential of PAN/SL ACNFs as the adsorbent for the removal of Pb(II) ions from aqueous solution.


2007 ◽  
Vol 124-126 ◽  
pp. 1257-1260 ◽  
Author(s):  
Ke Chon Choi ◽  
Yongju Jung ◽  
Seok Kim ◽  
Soo Jin Park ◽  
Hyung Ik Lee ◽  
...  

We present the adsorption characteristics of uranyl ions on a new and innovative composite which was composed of a carboxymethylated polyethyleneimine (CM-PEI) and an activated carbon (F400) with a nanopore less than 2 nm in diameter. In this study, we examined the adsorption phenomena of uranyl ions on the CM-PEI/F400 composite and evaluated the adsorption data using various isotherm models. It was found that the adsorption of uranyl ions on the CM-PEI/F400 composite obeys the Langmuir isotherm model. In addition, it was observed that pH of solutions had great influence on the adsorption capacity of uranyl ions on the CM-PEI/F400 composite. Specially, the adsorption capacity of uranyl ions was linearly increased with an increase of pH at pH > 3.0.


2021 ◽  
Vol 1 (1) ◽  
pp. 30-36
Author(s):  
Khoirun Nisa Mahmud ◽  
Tan Hui Wen ◽  
Zainul Akmar Zakaria

Dye pollution in water system is of concern due to its carcinogenicity and its effect on aesthetic feature. One pollutant of interest is methylene blue (MB), which is a cationic dye widely used in industries. In this study, pyrolysis process was used to convert pineapple waste biomass (PWB) into useful adsorbents such as biochar (BC) and activated carbon (AC) to remove MB in water. BC was produced from pyrolysis of PWB (340 °C, 3 hours) whereas AC was prepared from pyrolysis of PWB (500 °C, 1 hour) impregnated with zinc chloride (ZnCl2). Prior to use, AC-PWB and BC-PWB were characterized for surface area, functional groups and surface morphology. Removal of MB was investigated by varying different parameters i.e. initial MB concentration and contact time, adsorbent dosage and temperature. Results obtained showed that AC-PWB has higher adsorption capacity than BC-PWB. The adsorption capacity and adsorption rate increased with increasing initial concentration of MB, adsorbent dosage and temperature until reached equilibrium condition. As a conclusion, PWB can be used as a useful raw material to produce cheap and environmentally friendly adsorbent to remove dye from solution.


2020 ◽  
Vol 12 (20) ◽  
pp. 8335
Author(s):  
Juanhong Wang ◽  
Zhaocheng Zhang ◽  
Dongyang He ◽  
Hao Yang ◽  
Dexin Jin ◽  
...  

Dye effluent has attracted considerable attention from worldwide researchers due to its harm and toxicity in recent years; as a result, the treatment for dye has become one of the focuses in the environmental field. Adsorption has been widely applied in water treatment owing to its various advantages. However, the adsorption behaviors of the new materials, such as the 2D black phosphorus (BP), for pollution were urgently revealed and improved. In this work, BP, black phosphorene (BPR), and sulfonated BPR (BPRS) were prepared by the vapor phase deposition method, liquid-phase exfoliating method, and modification with sulfonation, respectively. The three BP-based materials were characterized and used as adsorbents for the removal of methylene blue (MB) in water. The results showed that the specific surface areas (SSAs) of BP, BPR, and BPRS were only 6.78, 6.92, and 7.72 m2·g−1, respectively. However, the maximum adsorption capacities of BP, BPR, and BPRS for MB could reach up to 84.03, 91.74, and 140.85 mg·g−1, which were higher than other reported materials with large SSAs such as graphene (GP), nanosheet/magnetite, and reduced graphene oxide (rGO). In the process of BP adsorbing MB, wrinkles were generated, and the wrinkles would further induce adsorption. BPR had fewer layers (3–5), more wrinkles, and stronger adsorption capacity (91.74 mg·g−1). The interactions between the BP-based materials and MB might cause the BP-based materials to deform, i.e., to form wrinkles, thereby creating new adsorption sites between layers, and then further inducing adsorption. Although the wrinkles had a certain promotion effect, the adsorption capacity was limited, so the sulfonic acid functional group was introduced to modify BPR to increase its adsorption sites and promote the adsorption effect. These findings could provide a new viewpoint and insight on the adsorption behavior and potential application of the BP-based materials.


Investigate the possibility of treating wastewater containing heavy metals Zn2+ with activated carbon material prepared from macadamia shell with chemical activating agent H3PO4, showing high efficiency of adsorption of Zn2+. The results of the study showed that activated carbon with H3PO4 activating agent has high adsorption capacity, capable of handling Zn2+ best at pH = 4.5, dosage 1.8 g/L and time is 120 minutes. . The results show similarities with other research results and are capable of treating wastewater containing heavy metals Zn2+.


2020 ◽  
Vol 15 (2) ◽  
pp. 219-225
Author(s):  
Zhe Wang ◽  
Wenyao Li ◽  
Kenan Zhang ◽  
Haishun Jiang ◽  
Tao Ji ◽  
...  

The global abuse of antibiotics has led to many environment problems such as water pollution and drug-resistant bacteria. In this study, pure natural loofah was used as raw material to form powdered loofah activated carbon (LAC) after high temperature carbonization annealing, and sodium alginate (SA) with gel ability was combined to prepare loofah activated carbon sodium alginate (LAC-SA) hydrogel sphere by external emulsification method. This work showed that the adsorption mechanisms of LAC-SA microspheres for the three antibiotics of ofloxacin (OFO), tetracycline (TC) and norfloxacin (NFO) were in line by the psedosecond-order and the formula of Langmuir. The ofloxacin (OFO) antibiotic solution was used as a sample for cyclic adsorption experiment for 10 times and the cumulative adsorption amount exceeded 700 mg g–1.


2012 ◽  
Vol 549 ◽  
pp. 703-706
Author(s):  
De Yi Zhang ◽  
Jing Wu ◽  
Bai Yi Chen ◽  
He Ming Luo ◽  
Kun Jie Wang ◽  
...  

In this paper, a novel carbon/bentonite composite was prepared using sucrose as carbon source and bentonite as raw material. The characterization results shown that plenty of carbon particles distribute on the surface of the composite, and an abundant of functional groups, such as SO3H, carboxylic and hydroxyl groups, were successfully introduced onto the surface of the prepared composite. The adsorption capacity of the prepared composite for typical heavy metal ions and methylene blue deys also was investigated and compared with activated carbon and bentonite, the results show that the composite shows excellent adsorprion performance for heavy metal ions, and the adsorption capacity for Cu2+and Ni2+ increase by 136% and 591% than natural bentonite, respectSuperscript textively. The prepared composite with excellent adsorption performance could be used as a low-cost alternative to activated carbon for the treatment of heavy metal ions polluted wastewater.


Author(s):  
С.А.А. Ахмед ◽  
Е.С. Гогина

Адсорбция фенола на активированном угле считается одной из наиболее эффективных систем очистки сточных вод. В связи с этим изучена эффективность двух промышленных активированных углей российского производства для очистки сточных вод от фенола. Образцы включают порошкообразный активированный уголь (производимый из березового угля) и дробленый активированный уголь (производимый из скорлупы кокосового ореха). Исследование проведено в условиях изменения pH, влияния времени контакта и различных начальных концентраций фенола на процесс адсорбции. Исследование дополнительно расширено для выяснения кинетики адсорбции и модели изотерм Ленгмюра и Фрейндлиха. Результаты показали, что активированный уголь сохраняет максимальную адсорбционную способность в широком диапазоне pH – от 2 до 9. Это доказывает применимость угля для удаления фенола из различных сточных вод. Механизм адсорбции с использованием обоих образцов активированных углей следовал псевдовторому порядку и соответствовал модели изотермы Ленгмюра. Максимальная адсорбционная способность составила 185,19 и 172,41 мг/г для порошкообразного и дробленого угля соответственно, что свидетельствует о высокой эффективности удаления фенола из сточных вод. The adsorption of phenol on activated carbon is considered one of the most efficient wastewater treatment systems. In this regard, the effectiveness of two Russian manufactured industrial activated carbon types in removing phenol from wastewater has been studied. The samples included powdered activated carbon (made from birch charcoal) and crushed activated carbon (made from coconut shells). The study was carried out under the conditions of pH variation and the effect of contact time and different initial concentrations of phenol on the adsorption process. The study was further expanded to clarify the adsorption kinetics and the Langmuir and Freundlich isotherm model. The results showed that activated carbon retained the maximum adsorption capacity over a wide pH range of 2 to 9. This fact proves the usability of coal for removing phenol from various wastewater types. The adsorption mechanism using both activated carbon samples followed the pseudo-second order and corresponded to the Langmuir isotherm model. The maximum adsorption capacity was 185.19 and 172.41 mg/g for powdered and crushed coal, respectively, suggesting a high efficiency of phenol removal from wastewater.


Author(s):  
Hind Yaacoubi ◽  
Zuo Songlin

Abstract The objective of this research is to study the retention of two acidic anthraquinone dyes by Coconut-shell-based activated carbon. Ultimately, this work allows the valorization of this new material as an adsorbent. The effect of ammonia modification on the adsorption capacity of activated carbon towards remazol brilliant blue R19 (RB19) and acid blue 25 (AB25), has been studied. Coconut-shell-based activated carbon material was modified under ammonia flow at 900 and 1000 °C. The adsorption rates and isotherms of RB19 and AB25 on the resultant materials were then tested. The results show that ammonia modification remarkably increases the adsorption capacities of the activated carbons to RB19 and AB25, by a factor of 2–3 after treatment at 1000 °C (From 0.22 mmol g−1 and 1.04 mmol g−1 to 0.76 mmol g−1 and 2.19 mmol g−1 on AC and AC-O-N-1000, respectively). The increased adsorption capacity is attributed to the introduction of basic nitrogen-containing functional groups and enhanced pore development by ammonia modification. The collected experimental kinetic and isotherm data are well compatible with the intraparticle diffusion kinetic model and the Langmuir isotherm model. According to these results, the adsorption affinity is homogeneous in terms of surface functional groups and the surface bears a finite number of identical adsorption sites.


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