Effect of Ammonia Modification on Activated Carbons for the Removal of Acidic Anthraquinone Dyes

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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Role of Activated Carbon Precursor for Mercury Oxidation and Removal: Oxidized Surface and Carbene Site Interaction

Processes ◽

10.3390/pr9071190 ◽

2021 ◽

Vol 9 (7) ◽

pp. 1190

Author(s):

Regina Rodriguez ◽

Domenic Contrino ◽

David Mazyck

Keyword(s):

Activated Carbon ◽

Nitric Acid ◽

Gas Phase ◽

Functional Groups ◽

Bituminous Coal ◽

Activated Carbons ◽

Elemental Mercury ◽

Coconut Shell ◽

Mercury Removal ◽

Oxygen Functional Groups

Activated carbon (AC) is widely accepted for the removal of inorganic contaminants like mercury; however, the raw material used in the production of activated carbon is not always taken into consideration when evaluating its efficacy. Mercury oxidation and adsorption mechanisms governed by carbene sites are more likely to occur when graphitic-like activated carbons (such as those produced from high-ranking coals) are employed versus lignocellulosic-based ACs; this is likely due to the differences in carbon structures where lignocellulosic materials are less aromatic. In this research, the team studied bituminous coal-based ACs in comparison to coconut shell and wood-based (both less aromatic) ACs for elemental mercury removal. Nitric acid of 0.5 M, 1 M, and 5 M concentrations along with 10 M hydrogen peroxide were used to oxidize the surface of the ACs. Boehm titrations and FTIR analysis were used to quantify the addition of functional groups on the activated carbons. A trend was observed herein, resulting in increasing nitric acid molarity and an increased quantity of oxygen-containing functional groups. Gas-phase mercury removal mechanisms including physisorption, oxygen functional groups, and carbene sites were evaluated. The results showed significantly better elemental mercury removal in the gas phase with a bituminous coal-based AC embodying similar physical and chemical characteristics to that of its coconut shell-based counterpart. The ACs treated with various oxidizing agents to populate oxygen functional groups on the surface showed increased mercury removal. It is hypothesized that nitric acid treatment creates oxygen functional groups and carbene sites, with carbene sites being more responsible for mercury removal. Heat treatments post-oxidation with nitric acid showed remarkable results in mercury removal. This process created free carbene sites on the surface and shows that carbene sites are more reactive to mercury adsorption than oxygen. Overall, physisorption and oxygen functional groups were also dismissed as mercury removal mechanisms, leaving carbene-free sites as the most compelling mechanism.

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Surface Modification and Characterization of Coconut Shell-Based Activated Carbon Subjected to Acidic and Alkaline Treatments

Journal of Applied Science & Process Engineering ◽

10.33736/jaspe.435.2017 ◽

2017 ◽

Vol 4 (2) ◽

pp. 186-194 ◽

Cited By ~ 7

Author(s):

Tan I. A. W. ◽

Abdullah M. O. ◽

Lim L. L. P. ◽

Yeo T. H. C.

Keyword(s):

Activated Carbon ◽

Surface Morphology ◽

Surface Chemistry ◽

Pore Structure ◽

Surface Area ◽

Functional Groups ◽

Activated Carbons ◽

Coconut Shell ◽

Bet Surface Area ◽

Textural Characterization

Activated carbon derived from agricultural biomass has been increasingly recognized as a multifunctional material for various applications according to its physicochemical characteristics. The application of activated carbon in adsorption process mainly depends on the surface chemistry and pore structure which is greatly influenced by the treatment method. This study aims to compare the textural characteristics, surface chemistry and surface morphology of coconut shell-based activated carbon modified using chemical surface treatments with hydrochloric acid (HCl) and sodium hydroxide (NaOH). The untreated and treated activated carbons were characterized for their physical and chemical properties including the Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and textural characterization. The FTIR spectra displayed bands confirming the presence of carboxyl, hydroxyl and carbonyl functional groups. The Brunauer–Emmett–Teller (BET) surface area of the untreated activated carbon was 436 m2/g whereas the surface area of the activated carbon modified using 1M NaOH, 1M HCl and 2M HCl was 346, 525 and 372 m2/g, respectively. SEM micrographs showed that many large pores in a honeycomb shape were clearly found on the surface of 1M HCl sample. The pore structure of the activated carbon treated with 2M HCl and NaOH was partially destroyed or enlarged, which decreased the BET surface area. The modification of the coconut shell-based activated carbon with acidic and alkaline treatments has successfully altered the surface functional groups, surface morphology and textural properties of the activated carbon which could improve its adsorptive selectivity on a certain adsorbate.

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Comparative Study on the Adsorption Capacity of Activated Carbon Prepared from Lapsi Seed Stone and Betel nut using Phosphoric Acid

Journal of the Institute of Engineering ◽

10.3126/jie.v13i1.20361 ◽

2018 ◽

Vol 13 (1) ◽

pp. 153-159

Author(s):

Sahira Joshi

Keyword(s):

Activated Carbon ◽

Comparative Study ◽

Iodine Number ◽

Adsorption Capacity ◽

Functional Groups ◽

Activated Carbons ◽

Chemical Activation ◽

Betel Nut ◽

Surface Functional Groups ◽

Methylene Blue Number

This paper presents the comparative study on the adsorption capacity of activated carbons prepared from Lapsi (Choerospondias axillaris) seed stone and Betel (Areca catechu) nut. Activated carbons (ACs) were prepared from Lapsi seed stone (LSS) and Betel Nut (BN) by chemical activation with H3PO4 (in the ratio of 1:1 by weight) at 400°C. The pore structure of activated carbons was determined by iodine number and methylene blue number. Surface morphology of ACs was studied by scanning electron microscopy (SEM). Surface functional groups were analyzed by Fourier Transform Infra Red Spectroscopy (FTIR). As indicated by TGA analysis, the appropriate temperature required for carbonization was 400 ºC. Betel nut AC showed high iodine number and methylene number of 888 mg/gm and 369 mg/gm respectively. SEM micrographs of Betel nut AC show the presence of well developed pores on its surface. FTIR result indicated that both ACs contain −OH, >C=O groups as oxygen containing surface functional groups. Based on the result, the AC prepared from betel nut by activation with H3PO4 is comparable with commercial activated carbon and could be used as potential adsorbent for removal of pollutants from water and waste water.Journal of the Institute of Engineering, 2017, 13(1): 153-159

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An Environmentally Friendly Technology for Biomass Production Hydorchar from Renewable Resources

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.726-731.634 ◽

2013 ◽

Vol 726-731 ◽

pp. 634-637 ◽

Cited By ~ 2

Author(s):

Yan Qiu Lei ◽

Hai Quan Su

Keyword(s):

Activated Carbon ◽

Reaction Time ◽

Adsorption Capacity ◽

Functional Groups ◽

Biomass Production ◽

Renewable Resources ◽

Environmentally Friendly ◽

Hydrothermal Carbonization ◽

Removal Rates

A green and sustainable route for preparation of hydrochars from cornstalk by hydrothermal carbonization (200°C) was described. The morphology of the hydrochars changed with reaction time increased, the surface of the materials contained a large number of functional groups, showed higher adsorption capacity for Cr (VI) than activated carbon and the removal rates of Cr (VI) were 67% and 29% respectively (pH=1, 20°C).

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Pinecone-Derived Activated Carbons as an Effective Medium for Hydrogen Storage

Energies ◽

10.3390/en13092237 ◽

2020 ◽

Vol 13 (9) ◽

pp. 2237

Author(s):

Sara Stelitano ◽

Giuseppe Conte ◽

Alfonso Policicchio ◽

Alfredo Aloise ◽

Giovanni Desiderio ◽

...

Keyword(s):

Activated Carbon ◽

Hydrogen Storage ◽

Adsorption Capacity ◽

Surface Area ◽

Hydrogen Adsorption ◽

Activated Carbons ◽

Chemical Activation ◽

Textural Properties ◽

Biomass Waste ◽

Wavelength Dispersive Spectrometry

Pinecones, a common biomass waste, has an interesting composition in terms of cellulose and lignine content that makes them excellent precursors in various activated carbon production processes. The synthesized, nanostructured, activated carbon materials show textural properties, a high specific surface area, and a large volume of micropores, which are all features that make them suitable for various applications ranging from the purification of water to energy storage. Amongst them, a very interesting application is hydrogen storage. For this purpose, activated carbon from pinecones were prepared using chemical activation with different KOH/precursor ratios, and their hydrogen adsorption capacity was evaluated at liquid nitrogen temperatures (77 K) at pressures of up to 80 bar using a Sievert’s type volumetric apparatus. Regarding the comprehensive characterization of the samples’ textural properties, the measurement of the surface area was carried out using the Brunauer–Emmett–Teller method, the chemical composition was investigated using wavelength-dispersive spectrometry, and the topography and long-range order was estimated using scanning electron microscopy and X-ray diffraction, respectively. The hydrogen adsorption properties of the activated carbon samples were measured and then fitted using the Langmuir/ Töth isotherm model to estimate the adsorption capacity at higher pressures. The results showed that chemical activation induced the formation of an optimal pore size distribution for hydrogen adsorption centered at about 0.5 nm and the proportion of micropore volume was higher than 50%, which resulted in an adsorption capacity of 5.5 wt% at 77 K and 80 bar; this was an increase of as much as 150% relative to the one predicted by the Chahine rule.

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Effective Removal of Pb(II) Ions by Electrospun PAN/Sago Lignin-Based Activated Carbon Nanofibers

Molecules ◽

10.3390/molecules25133081 ◽

2020 ◽

Vol 25 (13) ◽

pp. 3081 ◽

Cited By ~ 2

Author(s):

Nurul Aida Nordin ◽

Norizah Abdul Rahman ◽

Abdul Halim Abdullah

Keyword(s):

Activated Carbon ◽

Adsorption Capacity ◽

Carbon Nanofibers ◽

Langmuir Isotherm ◽

Human Life ◽

Order Kinetic ◽

Solution Ph ◽

Adsorption Sites ◽

Activated Carbon Nanofibers ◽

Adsorption Technology

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.

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Adsorption of Soluble Metal Ions from Red Mud by Modified Activated Carbon

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.368-372.1541 ◽

2008 ◽

Vol 368-372 ◽

pp. 1541-1544 ◽

Cited By ~ 1

Author(s):

Hua Lei Zhou ◽

Dong Yan Li ◽

Guo Zhuo Gong ◽

Ya Jun Tian ◽

Yun Fa Chen

Keyword(s):

Activated Carbon ◽

Metal Ions ◽

Adsorption Capacity ◽

Red Mud ◽

Activated Carbons ◽

Valuable Metal ◽

Surface Areas ◽

Alumina Industry ◽

Modified Activated Carbons ◽

Almost All

Activated carbon was employed as the adsorption carrier for the metal ions in HCl solution of red mud, a solid waste produced in alumina industry. To improve the adsorption capacity to valuable metal ions, the activated carbon was modified by chemicals including HNO3, H2O2, H2SO4, H3PO4, NH3, Na2CO3, and tri-butyl phosphate (TBP). It was found that the modifications contributed the high adsorption capacity to almost all metal ions we focused on. In the case of TBP, remarkably higher adsorption capacity and selectivity of Sc3+ was observed. The correlation between the surface areas, IR spectra of those chemically modified activated carbons and adsorption was schemed.

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Effects of Maturity of Coconut Shells on Gold Adsorption Efficiencies of Derived Activated Carbons

Ghana Mining Journal ◽

10.4314/gm.v19i2.7 ◽

2019 ◽

Vol 19 (2) ◽

pp. 50-54

Author(s):

W. K. Buah ◽

J. Darmey ◽

F. Osei

Keyword(s):

Activated Carbon ◽

Activated Carbons ◽

Cyanide Solution ◽

Adsorption Capacities ◽

Relative Hardness ◽

Coconut Shells ◽

Activation Times ◽

Adsorption Rates

AbstractCoconut shells are used as precursors for preparation of activated carbons. The shells could vary in terms of their maturity. The influence of the maturity of the shells on gold adsorption efficiencies of derived activated carbons (ACs) from gold di-cyanide solution was investigated. The shells were pyrolysed at 900 ºC and the resulting chars were activated in steam at the same temperature for different durations. Assessment of the properties of the derived ACs revealed that; the hardness, gold adsorption capacities and rates of gold adsorption of the ACs depended on the maturity of the shells. The more matured the shells the harder the AC. The relative hardness and gold adsorption rates of the mature coconut shells activated carbons, HMand RM, respectively and those of the less mature shells, HLand RL, respectively were in the order of HM >HL and RM >RL. The relative hardness of the ACs derived from the more mature and less mature shells after 3 hrs activation were 99.3% and 94.0%, respectively and the gold adsorption rates were 5.78 mg Au/hr/gand 4.95 mg Au/hr/g, respectively. The adsorption rates and relative hardness depended on the duration of activation, where longer activation times resulted in increase in the adsorption rates and a decrease in relative hardness of the derived ACs. Keywords: Adsorption, Activated Carbon, Coconut Shells, Maturity, Relative Hardness

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Modification of Activated Carbon and its Application on Adsorption of UDMH Gas

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.634-638.1026 ◽

2013 ◽

Vol 634-638 ◽

pp. 1026-1030 ◽

Cited By ~ 2

Author(s):

Huan Chun Wang ◽

Xiao Li Gou ◽

Xiao Meng Lv

Keyword(s):

Activated Carbon ◽

High Temperature ◽

Transition Metal ◽

Surface Structure ◽

Functional Groups ◽

Room Temperature ◽

Activated Carbons ◽

Metal Solution ◽

Modified Activated Carbons

Two kinds of modified activated carbons were prepared by dipping with Zn(NO3)2 solution and by reducing in the atmosphere of N2 at high temperature respectively, which were characterized by FTIR,DSC,SEM and EDS. The surface structure was strongly changed in the process, along with the changes of chemical functional groups. The results of adsorption experiments revealed that the adsorbent capacities of UDMH gas at room temperature were enhanced obviously by modification compared with the raw activated carbon, especially dipped by transition metal solution. The mechanism probably involved was also discussed.

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Specific adsorption sites and conditions derived by thermal decomposition of activated carbons and adsorbed carbamazepine

Scientific Reports ◽

10.1038/s41598-020-63481-y ◽

2020 ◽

Vol 10 (1) ◽

Cited By ~ 1

Author(s):

Daniel Dittmann ◽

Paul Eisentraut ◽

Caroline Goedecke ◽

Yosri Wiesner ◽

Martin Jekel ◽

...

Keyword(s):

Thermal Decomposition ◽

Activated Carbon ◽

Activated Carbons ◽

Evolved Gas Analysis ◽

Gas Analysis ◽

Specific Adsorption ◽

Adsorption Mechanisms ◽

Adsorption Sites ◽

Adsorption Processes ◽

Inorganic Constituents

AbstractThe adsorption of organic micropollutants onto activated carbon is a favourable solution for the treatment of drinking water and wastewater. However, these adsorption processes are not sufficiently understood to allow for the appropriate prediction of removal processes. In this study, thermogravimetric analysis, alongside evolved gas analysis, is proposed for the characterisation of micropollutants adsorbed on activated carbon. Varying amounts of carbamazepine were adsorbed onto three different activated carbons, which were subsequently dried, and their thermal decomposition mechanisms examined. The discovery of 55 different pyrolysis products allowed differentiations to be made between specific adsorption sites and conditions. However, the same adsorption mechanisms were found for all samples, which were enhanced by inorganic constituents and oxygen containing surface groups. Furthermore, increasing the loadings led to the evolution of more hydrated decomposition products, whilst parts of the carbamazepine molecules were also integrated into the carbon structure. It was also found that the chemical composition, especially the degree of dehydration of the activated carbon, plays an important role in the adsorption of carbamazepine. Hence, it is thought that the adsorption sites may have a higher adsorption energy for specific adsorbates, when the activated carbon can then potentially increase its degree of graphitisation.

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