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Mixed matrix membranes (MMMs), an important class of organic-inorganic nanocomposite membranes, were developed to overcome some of the limitations of purely polymeric membranes. In this study to improve the separation performance of polyvinyl chloride (PVC) membranes, mixed matrix membranes (MMMs) were prepared from incorporating choline prolinate based ionic liquid (IL) in a the coke/metal-organic framework (MOF) (NH2-MIL-101(Cr)) as a filler in polyvinyl chloride (PVC), which can be viewed as a potential solution to the trade-off problem with polymeric membranes because of the combination of the processing versatility of polymers and the high gas separation capability. Coke/MOF/PVC and IL@AC/MOF/PVC MMMs with different filler loadings of 5, 10, and 15 wt% were prepared using solution casting method and characterized using Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM) with Energy-Dispersive X-ray Spectroscopy (EDX) analyses, and Brunauer-Emmett-Teller (BET) surface area test. The porous structure of MMMs nanocomposites causes to which coke/MOF composite effectively accelerate gas diffusion in the PVC matrix. The permeability date was measured at 288.15, 298.15, 308.15 and 318.15 K and pressure up to 4 bar for CO2 and N2. According to the outcome, the addition of the IL([Cho][Pro]) filler, the permeability of the AC/MOF/PVC MMMs is increased compared to the pure PVC membrane. The MMMs have the highest gas separation efficiency and performance above Robson's Upper Bound from 2008. [ABSTRACT FROM AUTHOR]

Simultaneous desulfurization and denitration by using activated coke is one of the most competitive technologies for cleaning low-temperature steel flue gases. The key to denitration performance relies on the regulation of active groups on the catalyst. In this work, the carboxyl and lactone groups with (NH4)2S2O8 oxidation and thermal treatment were found to mainly determined the catalytic activity. The results showed that (NH4)2S2O8-treated AC catalyst improved denitration activity at low temperatures, which was attributed to the increase in oxygen-containing groups of the AC, the thermal treatment enhanced the low-temperature activity while reduced the performance in (210–240 ℃). According to the characterization results and conformational relationship analysis, we revealed that the adsorption and activation of NH3 mainly depended on carboxyl groups during the middle-temperature range (210–240 ℃) NH3–SCR. Based on the advantage of middle-temperature denitration activity of modified activated coke, the carboxyl groups on activated coke were the most important active sites for the NH3–SCR reaction. Moreover, lactone groups, improved the denitration performance via promoting NO oxidation at low-temperatures range (120–150 ℃). However, the presence of only lactone groups in the 210–240 ℃ is not beneficial for the further promotion for denitration activity. This work initially reveals the decisive role of carboxyl and lactones groups of activated coke for the low-temperature NH3-SCR reaction, and guides the industrial arrangement of oxidation-modified AC as denitration catalyst. [ABSTRACT FROM AUTHOR]

Activated coke is a type of commonly used adsorbent for benzene series VOCs such as toluene, but traditional microporous activated coke usually faces the challenge of poor regeneration performance. Herein, based on self-made activated cokes with typical pore configuration, we found that adsorption and regeneration of toluene can be simultaneously enhanced by constructing hierarchical pore in activated coke. Correlations of pore configuration with toluene adsorption capacity and regeneration efficiency reveal that micropore contributes for strong toluene adsorption; meso-macropore provides mass transfer channel for toluene desorption and regeneration process. Hierarchical porous activated coke prepared from Zhundong subbituminous coal not only achieves the highest toluene adsorption capacity of 340.92 mg·g−1, but also can retain more than 90% of initial adsorption capacity after five adsorption-regeneration cycles. By contrast, micropore-dominant activated cokes can only retain 70% of initial adsorption capacity. Adsorption kinetic modelling on adsorption breakthrough curves shows that hierarchical porous activated coke prepared from Zhundong subbituminous coal exhibits high adsorption and diffusion rate constants of 14.39 and 33.45 min−1, respectively, much higher than those of micropore-dominant activated cokes. Due to the accelerated surface adsorption and diffusion processes induced by meso-macropore, toluene adsorption and regeneration behavior can be simultaneously improved. Results from this work validated the role of pore hierarchy in toluene adsorption-regeneration process, providing guidance for designing high-performance activated coke with synergistically improved toluene adsorption capacity and regeneration performance. [ABSTRACT FROM AUTHOR]

Mn oxides are confined within the porous structure of activated coke (ACO) via impregnation followed by calcination treatment. The Mn-ACO sample calcined at 600 °C (Mn-ACO600) demonstrated superior performance despite containing only a minute atomic ratio of 0.11 % Mn on its surface. This treatment led to a slight increase in the specific surface area and pore volume of ACO, with a significant enhancement in the proportion of micropores, rising from 54.2 % in ACO to 71.8 % in Mn-ACO600. Raman spectroscopy indicated additional defects in Mn-ACO, while XPS analysis confirmed the coexistence of Mn(II), Mn(III), and Mn(IV) oxides. Although ACO adsorption alone was ineffective in removing acesulfame (ACE), Mn-ACO600 achieved a removal rate of 19.0 %. The introduction of peroxydisulfate (PDS) further boosted the degradation of Mn-ACO600, with a Kapp value that was 2.28 times of that of the combined Mn-ACO600 adsorption and PDS oxidation process, indicating a remarkable synergistic effect. To optimize the experimental conditions, a response surface methodology design analysis was conducted, revealing that solution pH and the dosage of Mn-ACO600 were crucial factors. Furthermore, the study confirmed non-radical oxidizing species, such as ¹O2 and h+, played a predominant role in the process, with relatively minor contributions from radical oxidizing species. [ABSTRACT FROM AUTHOR]

The massive release of mercury undermines environmental sustainability, and with the official entry into force of the Minamata Convention, it is urgent to strengthen the control of mercury pollution. The effectiveness of activated coke (AC) in removing elemental mercury (Hg0) from high temperatures and sulfur nonferrous smelting flue gas before acid production was studied. Experimental results indicated that the optimal temperature for Hg0 adsorption by AC was 150 °C. And the adsorption of Hg0 by AC was predominantly attributed to physical adsorption. Flue gas components (SO2 and O2) impact studies indicated that O2 did not significantly affect Hg0 adsorption compared to pure N2. Conversely, SO2 suppressed the adsorption capacity, while the simultaneous presence of SO2 and O2 exhibited a synergistic effect in facilitating the removal of Hg0. The characterization results of X-ray photoelectron spectroscopy (XPS) indicated that the SO2 molecule favored to anchor at the Oα site, leading to the formation of SO3. This subsequently oxidized the mercury to HgSO4 instead of HgO. The study demonstrates that cheap and easily accessible AC applications in the adsorption of mercury technology may help improve the sustainability of the circular economy and positively impact various environmental aspects. [ABSTRACT FROM AUTHOR]

The adsorption of phenol (Ph), 4-chlorophenol (CP), and 4-cresol (MP) from aqueous solutions on three carbonaceous materials of diverse origins but similar specific surface areas was investigated. Vulcan XC72 carbon black (CB), AKP-5 activated coke (AC), and activated tire pyrolysis char (AP) were examined as adsorbents. The kinetics and equilibrium adsorption, as well as the influence of pH and ionic strength of each solution on the adsorption process, were studied. The results revealed that the adsorption was pH-dependent and preferred an acidic environment. The presence of an inorganic salt in the solution (ionic strength) did not affect the adsorption processes of the three adsorbates. The pseudo-first- and pseudo-second-order equations, as well as the Weber–Morris and Boyd kinetic models, were used to describe the adsorption kinetics. It was found that equilibrium was reached for all adsorbates after approximately 2–3 h. Adsorption kinetics followed a pseudo-second-order model, and the adsorption rate was determined by film diffusion. The adsorption isotherms were described using the Langmuir and Freundlich equations. The results revealed that the adsorption processes of Ph, CP, and MP on all three adsorbents from the water were better described by the Langmuir model. The adsorption of CP was the most efficient, the adsorption of MP was slightly weaker, and the adsorption of phenol was the least efficient. [ABSTRACT FROM AUTHOR]

Both sludge biochar (BC) and activated coke (ACO) are hierarchical while their surface properties have a large disparity. We show that sludge biochar pyrolyzed at 600°C (BC600) outperforms biochar produced at other temperatures for a range of biomass feedstock. BC600 displays lower carbon content, lower surface area, and importantly more abundant surface oxygen-containing functional groups when compared with ACO. BC600 and ACO were used to activate peroxydisulfate (PDS) for tetracycline oxidation while the degradation mechanisms were comprehensively discussed. Interestingly, ACO demonstrated a particularly higher performance where activating PDS compared with BC600. The Kapp value for the synergetically combined ACO-PDS process was 2.15 times that of the sum of adsorption and PDS oxidation processes alone, while it was 1.72 times for the BC600-PDS process. Solution pH had a more dramatic influence on BC600 than on ACO. Quenching experiments proved that both OH• and SO4 •-contributed insignificantly while most of the degradation was attributed to superoxide radical (O2 •-), singlet oxygen (1O2), and active holes (h+). After reducing carbonyl groups on both carbons by KBH4 in absolute alcohol, quenching experiments did not indicate the key role of carbonyl groups for 1O2 generation. Nonradical pathway proved dominant in the carbon/PDS catalytic process. Excellent reusability and stability for ACO was observed in repeated use experiments. [ABSTRACT FROM AUTHOR]

SO2 and NOx in flue gas are serious environmental pollutants. As an excellent adsorbent, activated coke has good application potential in flue gas desulfurization and denitrification. In this study, different concentrations of NH3 and K2CO3 solutions were used to modify the activated coke made from biomass and coal, and then separate and coordinated desulfurization and denitrification experiments were carried out. The adsorption efficiency of activated coke and the adsorption capacity of SO2 and NO were compared, and the adsorption relationship between SO2 and NO was clarified. The changes of the surface functional groups of activated coke before and after adsorption and the forms of SO2 and NO after adsorption were analyzed by Fourier transform infrared spectrometer and X-ray diffractometer patterns. Results show that K2CO3 and NH3 modification can promote the adsorption of SO2 and NO in activated coke, and K2CO3 modification is more significant for improving the denitrification and desulfurization capacity. When the unmodified activated coke synergistically adsorbs SO2 and NO, there is a competitive adsorption between NO and SO2. However, when the activated coke modified with K2CO3 solution and NH3 synergistically adsorbs SO2 and NO, both have a promoting effect. After the adsorption of NH3-modified activated coke, CaSO4 and Na2SO4 crystals will appear. K2SO4 will exist after the adsorption of activated coke modified with K2CO3 solution. [ABSTRACT FROM AUTHOR]

Simultaneous removal of Hg0 and H2S over a regenerable activated coke supported Fe2O3 catalyst (Fe2O3/AC) was studied in simulated coal-derived syngas. It was found that the Fe2O3/AC catalyst exhibited high capability for Hg0 and H2S removal, which was attributed to the catalytic oxidation activity of Fe2O3. Its capability for Hg0 and H2S removal increased with an increase of Fe2O3 loading amount, and the highest was at 150 °C for Hg0 removal. CO and H2 showed no obvious effect on Hg0 removal by Fe2O3/AC, while H2S had a promotion effect, which was due to S and FeSx produced by the H2S reaction on Fe2O3/AC. The results of SEM-EDX and the temperature programmed desorption experiment (TPD) revealed that Fe2O3 played a critical role in Hg0 oxidation, and HgS was generated upon the reaction of Hg0 with H2S on Fe2O3/AC. The used Fe2O3/AC catalyst after Hg0 and H2S removal could be effectively regenerated and still had high capability for Hg0 and H2S removal. [ABSTRACT FROM AUTHOR]

Activated coke-based catalysts have attracted extensive attention in denitration by selective catalytic reduction by NH3 (NH3-SCR), due to their excellent catalytic performance at low temperature. In the paper, the V2O5/AC catalyst was prepared by the impregnation method to investigate the effect of pre-oxidation process on its NH3-SCR activity. Activity test results show that the V2O5/AC catalyst with 4-h pre-oxidation exhibits the best NOx removal efficiency, which reaches the NOx conversion is over 75% in the range of 200–240 °C and exhibits an excellent resistance to SO2 and H2O. Characterization results demonstrate that the V4+ was oxidized by oxygen molecule during pre-oxidation process, which contributes to the formation of V5+ ions and surface-active oxygen species. The surface-active oxygen species are conducive to promoting the "fast SCR" reaction; thus, the pre-oxidized process can contribute to the superior NH3-SCR performance for V2O5/AC catalyst at low temperature. [ABSTRACT FROM AUTHOR]

The low temperature of sintering flue gas limits the application of common vanadium‐ and titanium‐based catalysts if flue gas is not reheated. In this study, cylindrically molded activated coke was prepared from steel slag and coke powder of an iron and steel plant for low‐temperature denitration. The fraction of activated coke precursor and activation conditions were optimized by orthogonal experiments and the response surface method, respectively. Denitration tests on low‐temperature simulated sintering flue gas and characterization of the physical and chemical properties of the activated coke were carried out. Fe2O3 of steel slag showed catalytic reductive activity. [ABSTRACT FROM AUTHOR]

This article discusses the desulfurization and denitrification integrated purification technology for activated coke. This technology has been widely used in globally due to its ability to simultaneously remove NOx, SO2, dioxin, and dust from the flue gas. The approach discussed adopts a cross‐flow method in which the activated coke flows from the top to the bottom in the adsorption tower, and the flue gas passes through the activated coke bed horizontally from the side. To create a more economically appealing solution, the waste heat recovery system is optimized and a regeneration gas processing system is added to recycle the gas with a high concentration of SO2. In this process, first desulfurization and then denitrification. The denitrification process is performed by selective catalytic reduction of NOx with NH3 reaction (NH3‐SCR). The results show that under the flue gas condition (NOx = 300 mg/Nm3 and SO2 = 200 mg/Nm3), SO2 is almost completely removed and the NOx removal efficiency is greater than 80%. After SO2 adsorption, the activated coke can be regenerated in a regeneration furnace at 400–450°C and the highly concentrated SO2 produced during the regeneration process can be further used for the production of ammonium sulfate. The purpose of the regeneration reaction of activated coke is to reactivate and recover the activated coke. Finally, the cost analysis results of the system show that the desulfurization and denitrification integrated purification technology for activated coke has excellent economic benefits. [ABSTRACT FROM AUTHOR]

The advanced treatment of printing and dyeing wastewater by adsorption using activated coke was studied. Specifically, the effects of adsorption conditions on wastewater treatment were examined by adsorption experiments. Meanwhile, the adsorption behaviors of organic pollutants by activated coke were investigated by the adsorption kinetics and isotherms. The chemical oxygen demand (COD) removal met the printing and dyeing wastewater discharge requirement under the conditions of initial COD concentration 158 mg/L, adsorption time 360 min, activated coke concentration 30 g/L and adsorption temperature 308 K. After adsorption, 53.86% of COD was removed. The adsorption kinetics of COD by activated coke followed the pseudo-second-order model and the adsorption isotherms could be expressed by the Freundlich model. Moreover, thermal regeneration of spent activated coke was studied. Specifically, the effects of regeneration conditions on the thermal regeneration efficiency of spent activated coke were examined by thermal regeneration experiments. Meanwhile, the reusability of activated coke for organic pollutants removal was evaluated by the successive adsorption-regeneration cycles. 98.13% of thermal regeneration efficiency could be achieved under the conditions of regeneration temperature 1,073 K, regeneration time 30 min and CO2 flow rate 150 mL/min, and activated coke still maintained 92.54% of regeneration efficiency after ten adsorption-regeneration cycles. [ABSTRACT FROM AUTHOR]

Microwave modification of activated coke is reported as a green and simple route to improve its synergistic desulfurization and denitrification. The results showed that microwave irradiation improved the specific surface area and pore volume, decreased the pore size, and activated the surface functional groups of the activated coke. Under the conditions of a microwave power of 500 W and a modification time of 30 min, the specific surface area was increased from 185.9 m²/g to 351.7 m²/g, the pore volume increased from 0.042 m³/g to 0.111 m³/g, and the characteristic peak strengths of C=C and -OH drastically increased. When the reaction temperature was 140 °C and the O2 concentration was 10% (by volume), the desulfurization and denitrification efficiency were maintained at levels greater than 90% and 80% for 30 min and 15 min, respectively. The C-O content increased, and the C=C and -OH content decreased after undergoing desulfurization and denitrification. The desulfurization and denitrification products were primarily sulfate and nitrate. This provides theoretical support for the application of microwave modified active coke in low temperature desulfurization and denitrification. [ABSTRACT FROM AUTHOR]

The aim of this study was to study the influence factors of selective catalytic reduction (SCR) of NO with NH3 in flue gas and to clarify the mechanism of SCR over activated coke (AC). An AC in various simulated flue gases for reduction of NO was examined in a fixed-bed reactor. X-ray photoelectron spectroscopy (XPS) was used to performhigh-resolution scanning of surface N element. The results indicate that the presence of O2 in flue gas facilitates the NO reduction in SCR. Higher polarity of H2O molecule may inhibit NH3 or NO adsorption on the surface of ACs, so that NO reduction has been restrained. A lowest NO conversion was tested at 250°C in the temperature range of 100–350°C, meaning that may presence of different SCR mechanism at low or high temperature. Adsorption of NH3 below 250°C is dominated by physical adsorption and adsorption of NH3 higher than 250°C is dominatedby the chemical reaction between NH3 and AC base on the determination of XPS and adsorption capacities of NH3. There was a good correlation between adsorption capacity of NH3 and NO conversion, which indicated that NH3 adsorption is a key step in SCR regardless of whether NH3 was physically or chemically adsorbed on the AC. [ABSTRACT FROM AUTHOR]

In this study, Manganese oxide (MnO x) was supported on activated coke modified by (NH 4) 2 S 2 O 8 (ACs) to obtain novel MnO x /ACs catalysts with high NO x removal performance by excessive impregnation method. The influence of precursor and loading amount of MnO x on the catalytic efficiency were studied. The Mn 3 O 4 supported on ACs samples prepared with manganese acetate tetrahydrate as precursor and the loading amount of 8% Mn is the most effective in NO x removal among modified samples and its removal efficiency is 97% at 180 °C. And the adsorption state and reaction behaviors of NH 3 , NO and O 2 on MnO x /ACs catalysts were measured by in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS) in different conditions in order to study the effect of MnO x and the reaction mechanism. The results suggested that Eley-Rideal and Langmuir-Hinshelwood mechanism existed simultaneously for the selective catalytic reduction of NO over the MnO x /ACs catalyst. Image 1 • High efficiency of DeNO x catalyst was formed by Mn 3 O 4 loaded on active coke. • The best precursor agent and loading amount were discussed. • The mechanism of the reaction occurred on the catalyst was studied. [ABSTRACT FROM AUTHOR]

Low‐rank activated coke (AC) is widely used for industrial flue gas purification due to its multipollutant cooperative removal capability. To enhance the denitrification capacity of AC for the selective catalytic reduction (SCR) of NO with NH3, several transition metal (Fe, Mn, Ce, V) oxides were uniformly loaded into AC by solvent impregnation. Compared to untreated AC, modified AC showed excellent denitrification efficiency above 90%. N2 adsorption‐desorption and Raman spectroscopy techniques were used to characterize the pore size distribution and crystal structure of AC samples. The introduction of transition metal oxides had little effect on the pore structure of AC but increased the nitrogen‐containing functional groups, which facilitated NO removal. Moreover, x‐ray photoelectron spectroscopy (XPS) was used to analyze the valence changes of metal elements before and after denitrification. After the reaction, the content increase of the low‐valence metal oxides indicated that the transition metal oxides were involved in the reaction of NO with NH3. High‐valence metal oxides oxidized NO to NO2, which reacts more easily with NH3, thereby increasing the denitrification efficiency. Importantly, in the presence of SO2, modified AC still presented high denitrification performance. This transition metal oxides doping method can effectively improve the ability of low‐rank AC to remove NO in multi‐contaminant flue gas. [ABSTRACT FROM AUTHOR]

Impregnating CuCl2 on AC (activated coke) support to synthesize xCuCl2/AC showed superior activity with higher 90% Hg0 removal efficiency at 80–140 °C, as well as a lower oxygen demand of 2% O2 for Hg0 removal. The acceleration on Hg0 removal was observed for NO and SO2. The BET, SEM, XRD, XPS, TPD, and FT-IR characterizations revealed that the larger surface area, sufficient active oxygen species and co-existence of Cu+ and Cu2+ may account for the efficient Hg0 removal. In addition, the low demand of gaseous O2 was contributed to higher content of active oxygen and formed active Cl. After adsorbing on Cu sites, Cl sites, and surface functional groups, the Hg0(ads) removal on xCuCl2/AC was proceeded through two ways. Part of Hg0(ads) was oxidized by active O and formed Hg0, and the other part of Hg0 combined with the active Cl, which was formed by the activation of lattice Cl with the aid of active O, and formed HgCl2. Besides, the Hg2+ detected in outlet gas through mercury speciation conversion and desorption peak of HgCl2 and Hg0 further proved it. As displayed in stability test and simulated industrial application test, CuCl2/AC has a promising industrial application prospect. [ABSTRACT FROM AUTHOR]

To improve the denitrification efficiency for the selective catalytic reduction of NO with NH3 in the flue gas purification process, a low-rank activated coke (AC) was treated with ammonia (NH3·H2O) solution or nitric acid (HNO3) solution to increase the content and type of nitrogen-containing functional groups, and then the role of nitrogen-containing functional groups in the reduction of NO was analyzed. The modified AC samples were characterized by N2 adsorption/desorption to determine the pore structures and by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy to detect the surface functional groups. After modification, the content of oxygen-containing functional groups on the AC surface increased, including quinone, lactone and carboxyl, which are favorable for SO2 adsorption. Meanwhile, the type and content of nitrogen-containing functional groups on the AC surface changed; these groups fall into two categories: active groups and non-active groups. Before and after the denitrification process, the regular changes in the content of active and non-active groups showed that the active groups with pyrrole-like or pyridine-like structures can promote NO adsorption and then strengthen the denitrification. On the other hand, active groups may be reduced by NH3 or oxidized by O2, referring to side reactions, to generate non-active groups such as nitro, nitrate, amine and imine. More importantly, the role of nitrogen-containing functional groups was identified in the denitrification process. This chemical modification method is effective for improving the performance of low-cost AC since the employed chemicals are commercially available. [ABSTRACT FROM AUTHOR]

Porous materials such as activated cokes have been widely utilized in the adsorption removal of atmospheric SO 2 emission. Pore configuration of coke is a key factor affecting its SO 2 rapid adsorption dynamics, which is critically important for fluidization adsorption craft. Herein, activated coke adsorbents with typically microporous structure and hierarchically porous structure were prepared by a catalytic physical activation method from Chinese large-reserve Zhundong coal, which were used as model adsorbents to investigate the effect of pore configuration on SO 2 fluidized adsorption dynamics. SO 2 fluidized-state adsorption experiments indicate that hierarchically porous coke has a more rapid initial adsorption dynamic than microporous type coke, and coke with 44.2% meso-/macropores volume shows the highest initial adsorption rate of 7.37 mg g−1·min−1. Additionally, the fitting of Weber-Morris model provides the dominate factors for SO 2 adsorption kinetics in each sub-process: SO 2 adsorption capacity of microporous-dominated adsorption stages account for 70%–80% of total, and when it comes close to adsorption saturation, the main dominant factor of kinetic becomes the ratio of meso-/macropores volume. This work is of significance for the application of SO 2 adsorption craft in fluidized bed and also provides insight into the role of hierarchically porous configuration in gas molecule rapid adsorption. Image 1 • Model adsorbents for investigating the effect of pore structure on adsorption dynamics are provided. • Hierarchically porous coke shows higher initial adsorption rate of SO 2 in fluidized bed. • Dominate factors of SO 2 adsorption dynamics in each sub-process are elucidated. [ABSTRACT FROM AUTHOR]

Activated coke was prepared by CO2 activation using solid waste fine blue-coke as main raw material and coal direct liquefaction residue (DCLR) as binder. The activated coke was characterized by BET, XRD, and infrared analysis. The flue gas desulfurization experiment was carried out with a fixed bed reactor and activated coke as the adsorbent. The experimental results show that coal direct liquefaction residue pyrolysis process will produce a large number of cohesive colloids, further increasing the strength of the activated coke. BET analysis shows that there is abundant microporous structure in the activated coke, infrared analysis shows that the activated coke contains abundant surface functional groups, and XRD shows that the crystallization degree of the activated coke is high. At lower temperature, SO2 and O2 have competitive adsorption on the surface of activated coke, if the concentration of water vapor is too high, a water film will be formed on the surface of activated coke, which will hinder the adsorption of SO2 by activated coke. The initial concentration of SO2 is 700 ppm, the adsorption temperature is 80 °C, the oxygen concentration is 9%, and the concentration of water vapor is 8%. The removal of SO2 by activated coke is better, and the desulfurization rate reaches 97%. [ABSTRACT FROM AUTHOR]

To reduce chemical carbon consumption in activated coke technology used for flue gas purification, the carbon consumption mechanism of commercial activated coke in the presence of water vapor was studied. A fixed-bed reactor and a Fourier transform infrared (FTIR) spectrometer were combined to study the amount of carbon consumption. Temperature-programmed desorption (TPD) coupled with in situ diffuse reflectance infrared Fourier transform (in situ DRIFT) spectra were used to investigate functional group changes of activated coke. The sources and factors influencing carbon consumption in various adsorption atmospheres and in the N2 regeneration atmosphere were compared. Carbon consumption during the adsorption and regeneration process was mainly due to the release of C–O and C=C groups. The addition of H2O increased the formation of carbonates and carboxylic acids during the adsorption process, which decomposed during the regeneration process, thereby increasing carbon consumption. Carbon consumption was reduced during regeneration in an H2O-SO2 adsorption atmosphere, mainly because of the formation of C–S bonds, which reduced the formation of CO2. The C–N bonds generated in an H2O-NO adsorption atmosphere were decomposed during the regeneration process, thereby increasing carbon consumption. In a complex atmosphere of SO2, NO, NH3, and H2O, SO2 was absorbed by NH3, and the amount of carbon consumption was consistent with that in the NO atmosphere during the regeneration process. The total carbon consumption in various adsorption atmospheres ranged from 85.4 to 125.2 μmol/g. Compared with an anhydrous atmosphere, chemical carbon consumption increased by 6.5–14.3% in the presence of H2O. Chemical carbon consumption was reduced by decreasing the H2O concentrations, which provides a reference concept for reducing the operating cost of the activated coke process in industry. [ABSTRACT FROM AUTHOR]

Fine blue-coke and direct liquefaction residue of coal are byproducts in the process of coal chemical production. They were taken as raw materials for the preparation of activated coke by the activation of carbon dioxide. The conditions (activation temperature, activation time and carbon dioxide flow rate) for activated coke preparation were optimized by response surface methodology (RSM). Results showed that activation temperature and activation time had a significant effect on the activated coke iodine adsorption value. The synergistic effect of activation time and carbon dioxide flow had a great influence on iodine adsorption value of activated coke. RSM optimization experiment obtained the optimum activation conditions were activation temperature of 850°C, activation time of 90min and carbon dioxide flow rate of 60 mL/min. Under these conditions, the obtained activated coke iodine adsorption value can reach 401 mg/g, which could meet the needs of industrial desulphurization. [ABSTRACT FROM AUTHOR]

In order to study the mechanism of selective catalytic reduction of activated coke to remove NO in low-temperature flue gas and provide some theoretical basis for the development of related technologies. The pore size distribution and BET specific surface area of AC were obtain by data analyzing of N2 adsorption/desorption isotherm at − 196 °C and carbon matrix and surface chemistry of virgin activated coke samples were characterized by acid–base titration and XPS. The process of selective catalytic reduction of activated coke (AC) samples with NH3 as reducing agent was studied in a fixed bed reactor at 150 °C. The result shows that pore size distribution or BET specific surface of activated cokes have not correlation with denitrification activity for SCR. The NO reduction activities of the activated cokes are apparent to increase with their surface oxygen element content and total amount of acidic sites. Obviously there is good linear relationship between the NH3 adsorption capacity and activity for SCR with linear correlation coefficient 0.943. It has been presented that adsorption of NH3 on acidic functional groups in the edge of large polycyclic aromatic ring of activated coke is key rate controlling step in the SCR heterogeneous catalytic reaction. [ABSTRACT FROM AUTHOR]

A series of Mn–Ni/AC (AC, activated coke) catalysts were synthesized by the impregnation method for the removal of elemental mercury (Hg0) from simulated flue gas. The samples were characterized by BET, ICP-OES, SEM, XRD, XPS, H2-TPR, FT-IR, and TGA. Mn6Ni0.75/AC exhibited optimal removal efficiency of 96.6% in the condition of 6% O2 and balanced in N2 at 150 °C. The experimental results showed that both O2 and NO facilitated Hg0 removal. SO2 could restrain the Hg0 removal in the absence of O2, while the inhibitory effect of SO2 was weakened with the aid of 6% O2. In addition, H2O exhibited a slightly negative influence on Hg0 removal. The characterization of the samples indicated that Mn6Ni0.75/AC possessed larger specific surface area, higher dispersion of metal oxides, and stronger redox ability. In the meantime, the results of XPS and FT-IR demonstrated that the lattice oxygen and chemisorbed oxygen made contributions to Hg0 removal and the consumed oxygen could be compensated by the redox cycle of metal oxides and gas-phase O2. Meanwhile, the mechanisms of Hg0 removal were proposed based on the above studies. [ABSTRACT FROM AUTHOR]

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Abstract: BACKGROUND: Pyrolusite was used as additive to prepare coal‐based activated coke (AC) for low‐temperature NO removal. The pyrolusite modified AC was prepared by a blending method, and the denitrification performance was evaluated in a lab‐scale simulated fixed‐bed reactor. RESULTS: The blending of pyrolusite promoted the specific surface area and pore structure of AC, even though the MnO2 and Fe2O3 showed inhibitory effects when blended separately. Both the basic and acid sites of AC‐Mn(x) increased owing to the participation of the blended MnO2 during the activation, while the blending of Fe2O3 showed an inhibited effect. AC‐P10 showed the highest NO removal efficiency at 74.2%, which was 32.8%, 27.0% and 24.2% higher than that of AC, AC‐Mn4 and AC‐Fe6. The operating temperature adaptability and stability of catalysis activity of AC‐P10 are good. Manganese is the main catalyst of AC‐P(x), and Fe is an accelerant to stimulate the catalytic activity of Mn. The extremely high NO removal activity of AC‐P(x) was due to the synergistic effect of surface functional groups and metals, but the catalysis of metals played a more important role. CONCLUSION: Pyrolusite is suitable to prepare the AC‐based denitrification catalyst (AC‐P(x)) for SCR NO removal because the Mn and Fe contained in the pyrolusite showed a synergistic effect. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND Low-cost coal-based carbonaceous material has attracted special attention for removal of organics from industrial wastewaters. In this study, coal tar-derived activated carbon ( AC1) and lignite activated coke ( AC2) were employed to identify the fundamental factors that facilitate the selection of suitable adsorbents for removing recalcitrant organic contaminant ( ROC) from bio-treated coking wastewater ( BTCW). RESULTS Results show that AC2 exhibited superior ROC adsorption efficiency (57.9%), which was apparently higher than that of AC1 (45.2%), in spite of its lower specific surface area (238.05 m2 g−1) and pore volume (0.21 cm3 g−1). FTIR and XPS characterization indicated that AC2 possessed a distinctive configuration of functional groups, of which the basic oxygenic groups (60%) provided more hydrophobic adsorption sites for ROC. 3D-EEM spectra suggested more aromatics and fluorescent materials were removed by AC2 compared with AC1. GC-MS further confirmed that AC2 had stronger affinity with the ROC in BTCW, especially for PAHs and heterocyclic compounds. CONCLUSION Surface chemistry is vital to the adsorption of ROC from coking wastewater, of which basic oxygenic functional groups have specific interactions with PAHs and heterocyclic compounds. The mechanism that best explains ROC adsorption is π-π dispersion between carbon materials and the pollutants, as well as the hydrogen-bonding interactions. This study provides an encouraging and practical guide to ROC adsorption from BTCW in future operations. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

In this study, pyrolusite modified columnar activated coke (AC-P) was prepared through blending coal chars with an additive (i.e. pyrolusite). The effect of preparation process on the properties of obtained activated coke and the effects of operating conditions on desulfurization performance of AC-P were investigated. The results show that the blending ratio of coal tar and molding pressure could affect the iodine value and drum strength of prepared activated coke. The orthogonal experiment results show that the optimal activation conditions for activated coke were 950°C of activation temperature, 60 min of activation time, and 0.5 of MH2O/ MC. When pyrolusite was blended into activated coke, the product yield, iodine value, and desulfurization performance of all AC-P samples increased significantly. The optimal desulfurization operating conditions were: SO2 concentration at 2000 ppmv, bed temperature at 80°C, O2 content at 8%, water vapor content at 10%, and space velocity at 600 h−1. The results demonstrate that the AC-P is a kind of very promising adsorbent/catalyst in industrial flue gas desulfurization application due to its low cost and good desulfurization capacity. © 2016 American Institute of Chemical Engineers Environ Prog, 35: 1679-1686, 2016 [ABSTRACT FROM AUTHOR]

FeO and CeO modified activated coke (AC) synthesized by the equivalent-volume impregnation were employed to remove elemental mercury (Hg) from simulated flue gas at a low temperature. Effects of the mass ratio of FeO and CeO, reaction temperature, and individual flue gas components including O, NO, SO, and HO (g) on Hg removal efficiency of impregnated AC were investigated. The samples were characterized by Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). Results showed that with optimal mass percentage of 3 % FeO and 3 % CeO on Fe3Ce3/AC, the Hg removal efficiency could reach an average of 88.29 % at 110 °C. Besides, it was observed that O and NO exhibited a promotional effect on Hg removal, HO (g) exerted a suppressive effect, and SO showed an insignificant inhibition without O to some extent. The analysis of XPS indicated that the main species of mercury on used Fe3Ce3/AC was HgO, which implied that adsorption and catalytic oxidation were both included in Hg removal. Furthermore, the lattice oxygen, chemisorbed oxygen, and/or weakly bonded oxygen species made a contribution to Hg oxidation. [ABSTRACT FROM AUTHOR]

Soil washing is a kind of physical method to remove organic matters from contaminated soil. However, its eluate after washing may result in secondary pollution to the environment. In this study, activated coke (AC) was used to remove organic pollutants from contaminated soil eluate. The effect of temperature, initial chemical oxygen demand (COD) and AC dosage on COD removal efficiency was investigated. The results showed that the organic matter can be removed in the eluate because the COD dropped a lot. When the AC dosage was 20 g⋅L-1, 88.92% of COD decreased after 480 min of adsorption at 50 °C. The process of adsorption can be described by the Redlich-Peterson isotherm. The adsorption was spontaneous and endothermic. The pseudo-second-order model can be used to describe the adsorption process. After adsorption, the acute toxicity of the eluate was reduced by 76%, and the water qualities were in agreement with Chinese discharge standard GB 14470.1-2002, which means the eluate could be discharged to the environment. [ABSTRACT FROM AUTHOR]

In this study, a novel activated coke (AC-P) was prepared by the blending method using bituminous coal as the raw material and pyrolusite as the catalyst. The physicochemical properties of prepared activated coke (AC) were characterized by BET, Fourier-Transform Infrared Spectroscopy, X-ray photoelectron spectroscopy and X-ray diffraction. The results indicated that the blended pyrolusite had a slight effect on the structural properties of AC, while the oxygenated functional groups on AC were increased and MnO2and Fe2O3in pyrolusite were reduced to MnO and Fe on the AC-P samples, respectively. All the AC-P samples significantly improved the removal of SO2, with the highest sulphur capacity (153 mg/g) for the AC blended with 8 wt% pyrolusite, which was 57.7% higher than that of the blank activated cock. This could be mainly attributed to the change in surface chemical properties of the AC-P samples and the active catalytic components in pyrolusite for the catalytic oxidation of SO2in desulphurization process. [ABSTRACT FROM AUTHOR]

A magnetic adsorbent, magnetic-activated coke (MAC), is incorporated with Fe3O4particles for removal of organic materials from 2,4,6-trinitrotoluene red water. The MAC is characterized by N2adsorption, Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscope, and energy dispersive X-ray spectroscopy. Adsorption of organic pollutants is evaluated systematically by varying the adsorbent dosage, exposure time, temperature, pH, and dilution ratios of 2,4,6-trinitrotoluene red water. The equilibrium adsorption data can be better fitted with the Freundlich isotherm than Langmuir isotherm except at 343 K. The adsorption kinetics follows a pseudo-second-order model and thermodynamic analysis indicates an endothermic and spontaneous adsorption process. The settling rate after adsorption suggests that the response of MAC under an external magnetic field is very fast. [ABSTRACT FROM PUBLISHER]

A novel modified activated coke (AC) desulfurizer prepared by impregnation of metal oxides (Fe, Cu, Ni, Mn, Co), rare earth elements (Ce, La), and potassium hydroxide (KOH) was investigated. Experimental results showed that the desulfurization (DeSO) efficiency of the AC impregnation of Fe (Fe/AC) was higher than other samples with impregnation of metal oxides at 120 °C and a space velocity of 8,000 h. At the same operating conditions, the Ce/AC was more effective in two samples with impregnation of rare earth elements. As the Fe content was increased from 3 to 5 % (mass %), DeSO efficiency increased significantly, and kept stable at higher Fe contents (10 %). The effect of desulfurization temperature was also investigated, which revealed that, with increasing temperature from 80 to 120 °C, the DeSO efficiency gradually increases, while the DeSO efficiency decreased with increasing temperature from 120 to 140 °C. [ABSTRACT FROM AUTHOR]

The novel adsorbent Cu-impregnated activated coke (CAC) has been successfully prepared using a Cu(NO) solution impregnated activated coke (AC). The optimum preparation conditions of CAC are the concentration of Cu(NO) of 0.1 mol/L, pH of 6, loading time of 4 h, and loading temperature of 333 K. The characterizations of CAC are analyzed by N adsorption, X-ray diffraction, scanning electron microscope, and energy dispersive X-ray spectroscopy. Also the adsorption behavior of CAC to organic materials in TNT red water is studied. The adsorption data are simulated by Freundlich isotherm and Langmuir isotherm. Below 333 K Freundlich isotherm is more suitable, while Langmuir isotherm model is more fitted when the temperature is higher than 333 K. The adsorption kinetics follows a pseudo second-order model, and thermodynamic analysis indicates an endothermic and spontaneous adsorption processes, and the process appears to be controlled by the chemisorption process. Chemical oxygen demand of 85.34 % can be removed as CAC prepared under optimized conditions is used as absorbent. In summary, CAC has excellent absorption characteristics and can be used in the removal of organic materials from TNT red water. [ABSTRACT FROM AUTHOR]

The measuring method of performance index for activated coke can be developed using the results in this paper. In the C0D adsorption experiment, the potassium hydrogen phthalate was used as standard reference material to measure the C0D-adsorption capacity of activated coke. Referring to the test method of phenol adsorption value of activated carbon, the measuring method of C0D adsorption value with activated coke was developed. The statistics theory was applied to analyze and process the experimental data. Based on rejecting the abnormal value the relation between C0D-adsorption capacity and dosing quantity of active coke was established. Furthermore, optimum sample weight of activated coke should be 1. 000 g considering the coefficient of variation. In this paper statistics method was used to guarantee the result' s reliability. [ABSTRACT FROM AUTHOR]

We used commercial activated coke (AC) as adsorbent and fixed-bed, FTIR, N adsorption, ion chromatograph as research methods to study the SO removal mechanism in the presence of O and HO and adsorbate (HSO) desorption mechanism by combined regeneration. The results showed that AC saturation sulfur retention (52.6 mg/g) in SO+O+HO atmosphere was 4.6 times as much as that (11.4 mg/g) in SO+O atmosphere and 5.0 times as much as that (10.6 mg/g) in SO+O atmosphere at 90 °C. O and HO were necessary in AC desulfurization process. Reaction of SO and HO (g) and condensation of sulfuric acid vapor were the dynamic of AC desulfurization process. Water vapor blowing in combined regeneration inhibited the reaction between HSO and carbon, and consequently reduced the chemical lost of carbon. AC cumulative quality loss (53.6%) of five-times in C-R was still less than that (62.4%) of three-times in H-R. Water vapor blowing inhibited reactivation effect, as a result reducing the changes of AC pore structure and surface functional groups. Adsorbate HSO generated in desulfurization evaporated to sulfuric acid vapor due to the high temperature in regeneration and was carried out by water vapor. [ABSTRACT FROM AUTHOR]

The activated coke is a promising support for catalysts, and it is important to study the performance of the activated coke catalyst on the removal of NOx. In the current research, a series of the activated coke-supported Mn–Cu catalysts are prepared by the incipient wetness impregnation method. The effects of the molar ration of Mn/Cu, the content of Mn–Cu, the calcination temperature, and reaction space velocity on NO conversion are investigated, and it was found that the 8 wt.% Mn0.7Cu0.3/AC had the best catalytic activity when the calcination temperature was 200 °C. The existence of SO2 caused the catalyst to deactivate, but the activity of the poisoning catalyst could be recovered by different regeneration methods. To uncover the underlying mechanism, BET, XPS, XRD, SEM and FTIR characterizations were performed. These results suggested that the specific surface area and total pore volume of the poisoning catalyst are recovered and the sulfite and sulfate on the surface of the poisoning catalysts are removed after water washing regeneration. More importantly, the water washing regeneration returns the value of Mn3+/Mn4+, Cu2+/Cu+, and Oα/Oβ, related to the activity, basically back to the level of the fresh catalyst. Thus, the effect of water washing regeneration is better than thermal regeneration. These results could provide some helpful information for the design and development of the SCR catalysts. [ABSTRACT FROM AUTHOR]

This study investigated influences of the open/close states of pores and porosity distribution of activated coke on the mechanical strength of common activated coke for the purification of coal-fired flue gas by analyzing pore structure, abrasive resistance, and compression strengths of 9 types of desulfurization and denitration activated cokes. Research conclusions are conducive to disclosing the influences of porosity characteristics of activated coke for the purification of coal-fired flue gas on mechanical strength, decreasing the physical consumption of activated coke in the recycling of flue gas purification systems, and lowering the purification cost of coal-fired flue gas. According to research results, pores in the ranges of 0–2 nm and 2–500 nm of activated coke are further developed after recycling using the coal-fired flue gas purification system, and the average compression strength of activated coke is about 70% of the added fresh activated coke. However, the abrasive resistance of the recycled activated coke which has a smooth surface is higher than that of the fresh activated coke. Open pores are the main cause of reduced compression strength of activated coke. Open pores in the range of 2–500 nm can destroy the compression strength of activated coke the most. The open/close states of pores cause no significant impacts on the abrasive resistance of activated coke, but pores with diameters ranging from 0–2 nm can destroy the abrasive resistance of activated coke most significantly. [ABSTRACT FROM AUTHOR]

Fe2O3/activated coke (AC) and Mn–Fe2O3/AC catalysts were prepared by an impregnation method for the low‐temperature selective catalytic reduction of nitrogen oxides (NOx) with ammonia (NH3). These catalysts were characterized by X‐ray fluorescence, X‐ray diffraction, isothermal N2 adsorption/desorption, X‐ray photoelectron spectroscopy, temperature program reduction by H2, and temperature programmed desorption of NH3 methods. Experimental results show that Fe2O3/AC catalyst with Mn addition exhibits an excellent NOx conversion at low temperature. Nearly more than 94.7% NOx conversion of 8Mn6Fe/AC catalyst was obtained at 180–240°C. The results of NH3 transient reaction and adsorption capacity of NOx indicate that 8Mn6Fe/AC catalyst has the capacity to adsorb gaseous NH3 and NOx on the catalyst surface. 6Fe/AC catalyst with a certain amount addition of Mn increases the dispersion of γ‐Fe2O3 phase, and ratios of Fe3+/(Fe2+ + Fe3+) and Oβ/(Oβ + Oα) obtained good reducibility and a lot of acid sites, which play important roles in improving the NOx conversion. The influences of SO2 and H2O on the NOx conversion over 8Mn6Fe/AC catalyst were also investigated. The good H2O poisoning resistance was obtained. [ABSTRACT FROM AUTHOR]