颗粒活性炭的一种再生工艺

利用处理过功能糖醇的颗粒活性炭,采用乙醇预处理,碳酸钠作为再生剂,通过再生柱对颗粒活性炭进行再生。通过再生颗粒活性炭再生效果评价实验,当乙醇体积分数为60%~70%、浸泡时间为2.5h、再生剂浓度为3%时、再生速度为每小时活性炭体积的3倍、正洗终点p H为9.5时再生处理量可达到再生柱体积的7.5倍。说明再生的炭对生产上样品处理仍起作用,且处理的效果也比较好。充分说明颗粒活性炭可以进行再生利用。     

Preloading hydrous ferric oxide into granular activated carbon for arsenic removal

Arsenic is of concern in water treatment because of its health effects. This research focused on incorporating hydrous ferric oxide (HFO) into granular activated carbon (GAC) for the purpose of arsenic removal. Iron was incorporated into GAC via incipient wetness impregnation and cured at temperatures ranging from 60 to 90 degrees C. X-ray diffractions and arsenic sorption as a function of pH were conducted to investigate the effect of temperature on final iron oxide (hydroxide) and their arsenic removal capabilities. Results revealed that when curing at 60 degrees C, the procedure successfully created HFO in the pores of GAC, whereas at temperatures of 80 and 90 degrees C, the impregnated iron oxide manifested a more crystalline form. In the column tests using synthetic water, the HFO-loaded GAC prepared at 60 degrees C also showed higher sorption capacities than media cured at higher temperatures. These results indicated that the adsorption capacity for arsenic was closely related to the form of iron (hydr)oxide for a given iron content For the column test using a natural groundwater, HFO-loaded GAC (Fe, 11.7%) showed an arsenic sorption capacity of 26 mg As/g when the influent contained 300 microg/L As. Thus, the preloading of HFO into a stable GAC media offered the opportunity to employ fixed carbon bed reactors in water treatment plants or point-of-use filters for arsenic removal.     

颗粒活性炭对模拟活性染料废水的吸附脱色效果

本文借助SEM观察了颗粒活性炭的表面形态结构,利用紫外-可见分光光度计测试分析了模拟染料废水吸附前后的吸光度变化,以考察颗粒活性炭种类、目数、染料废水浓度、pH值、吸附温度及时间对染液吸附脱色效果的影响。实验结果表明：椰壳活性炭的吸附脱色效果较煤质、果壳活性炭好;活性炭目数越大,其吸附脱色效果越好;活性炭对染料废水的吸附脱色效果随染料浓度的增大而呈线性函数下降;酸性环境下活性炭的吸附脱色效果好于碱性环境,pH值为5.5时,吸附脱色效果最好;吸附温度越高,脱色率越高,但升至一定温度后对吸附脱色效果增加不再显著;达平衡吸附前,增加吸附时间对活性炭的吸附脱色效果增加较为显著。     

颗粒活性炭吸附苯酚模拟废水的热力学和动力学研究

研究了颗粒活性炭对苯酚的静态吸附行为,分析了吸附热力学性质和动力学特征。实验结果表明:颗粒活性炭对水中苯酚的吸附量随其初始浓度的增加而增加,吸附6h可以达到平衡;吸附过程符合McKay二级吸附动力学方程,吸附等温线可用Freundlich等温吸附方程描述;颗粒内扩散不是吸附过程唯一的控制步骤。在不同温度下,颗粒活性炭对苯酚的吸附焓变ΔH、吸附熵变ΔS、吸附吉布斯自由能变ΔG均为负值,说明苯酚在颗粒活性炭上的吸附是一个自发、放热的过程,主要是以物理吸附为主。     

活性碳纤维负载钴酞菁对取代酚的催化氧化

为去除难降解的酚类物质,以活性碳纤维负载钴酞菁(CoPc-ACF)为催化剂、以H2O2为氧化剂组成新型催化氧化体系(CoPc-ACF/H2O2).该体系能充分发挥CoPc-ACF中活性碳纤维的吸附特性和钴酞菁的催化性能.以对硝基苯酚、对甲氧基苯酚和取代氯酚为对象,研究该体系对其的吸附催化氧化性能.采用UPLC检测酚类物...     

活性炭控制矿泉水中溴酸盐的选型及效果研究

为控制矿泉水中的溴酸盐含量,采用活性炭(GAC)技术对矿泉水和超纯水中的溴酸盐进行小试研究,同时根据碘吸附值和其溴酸盐控制能力进行GAC的选型,并进行中试实验,研究GAC对溴酸盐的去除效果。结果表明,当空床接触时间(EBCT)为5min时,矿泉水和超纯水中溴酸盐浓度均降至10μg·L-1以下。12种GAC的碘吸附值不同,GAC1、GAC2、GAC3和GAC4对溴离子和溴酸盐吸附结果显示,GAC1对水中溴离子去除效果最好,可以用于控制溴酸盐的生成;GAC2对水中溴酸盐去除效果最好,可以用于降低生成后溴酸盐含量。中试结果显示,臭氧化过程中生成的过量溴酸盐经GAC吸附,其含量可以降低至5μg·L-1以下。     

Catalytic oxidation of S(IV) in seawater slurries of activated carbon

Flue gas desulfurization (FGD) by means of SO2 absorption in seawater is a well-known process with a main drawback; due to the low S(IV) oxidation rate at the low pH values of the absorption tower effluent, a large oxidation basin is required. Laboratory reactor tests, in which a commercially available activated carbon was used, showed a significant catalytic effect. It is shown that the kinetic equation for the catalytic oxidation of S(IV), in seawater slurries of activated carbon, is first-order with respect to S(IV) and zero-order with respect to oxygen. The dependence of the kinetic constant with respect to pH, temperature, and catalyst size particles were also obtained.     

Adsorption of two coffee aromas from synthetic aqueous solution onto granular activated carbon derived from coconut husks

Soluble coffee production requires several processes that cause the loss and degradation of aromas, which reduces the quality of the final product. However, such aromas can be recovered into aqueous solution during the production process. Aromas must be separated from water, and pleasant compounds, such as benzaldehyde, must be separated from unpleasant compounds, such as acetic acid. In this study, the kinetic and thermodynamic parameters of benzaldehyde and acetic acid adsorption from synthetic single-solute aqueous systems onto commercial grade granular activated carbon derived from coconut husks were investigated. The contact time required to attain adsorption equilibrium of benzaldehyde was 6 h, while that of acetic acid was 10 h. Adsorption isotherm data revealed that the adsorption of benzaldehyde and acetic acid was exothermic and spontaneous in nature. Moreover, the isosteric heat of adsorption indicated that the adsorbent surface was energetically heterogeneous. The adsorption equilibrium was fitted according to Langmuir, Freundlich and Temkin isotherms.     

Three-component competitive adsorption model for fixed-bed and moving-bed granular activated carbon adsorbers. Part II. Model parameterization and verification

COMPSORB-GAC is a 3-component competitive adsorption kinetic model for granular activated carbon (GAC) adsorbers that was developed in Part I of this study, including a proposed procedure for determining model parameters in natural water applications with background natural organic matter (NOM). Part II of this study demonstrates the proposed parameterization procedure and validates the modeling approach by comparing predictions with experimental breakthrough curves at multiple empty-bed contact times for both fixed-bed and moving-bed reactors. The parameterization procedure consists of a set of independent, short-term experimental tests with fresh and batch preloaded adsorbents and then data fitting using both classic and recently developed theoretical expressions. The model and parameterization procedure simplifies NOM into two fictive fractions (pore-blocking and strongly competing) and incorporates three competitive effects that vary both temporally and axially in a GAC column (direct competition for sites, intraparticle pore blockage, and external surface pore blockage). With all three competitive mechanisms accounted for, the model could accurately predict breakthrough profiles for column lengths and durations that were much longer than those used for model parameterization. Model predictions that ignored one or more of the competitive mechanisms showed that each mechanism was important for different regions of the breakthrough curve. The external surface pore-blockage effect was predominant for the prediction of early breakthrough data, whereas direct competition for sites and intraparticle pore blockage were prevalent when predicting higher breakthrough levels and data later in the column run.     

载铜活性炭催化氧化糖蜜酒精废液COD的研究

用载铜活性炭和锰铁矿石内电解-催化氧化体系降解糖蜜酒精废液COD,最佳的催化剂制备条件:7.5%Cu(NO3)2溶液浸渍12h,260～300℃焙烧活化10～14h;Cu-AC催化剂可通过制备方法得以再生。     

The effect of water temperature on the adsorption equilibrium of dissolved organic matter and atrazine on granular activated carbon

The influence of water temperature on the adsorption of natural dissolved organic matter (DOM) on activated carbon has not been investigated intensively yet. In this study, batch experiments with granular activated carbon (GAC) have been carried out at three temperatures (5 degrees C, 20 degrees C, 35 degrees C) using a humic acid model water and different types of surface water (lake, river, canal). Furthermore, the adsorption of an anthropogenic contaminant, atrazine, was quantified in the absence and presence of DOM. The results indicate a significant influence of water temperature on the adsorption equilibrium of DOM and atrazine. Contrary to expectations, DOM and atrazine adsorption in surface water tends to be increased with increasing water temperature, whereas the extent of this effect is dependent on the type and concentration of DOM. Furthermore, the temperature effect on atrazine adsorption is controlled by competition of DOM and atrazine on adsorption sites. Some assumptions are proposed and discussed for explaining the temperature effects observed in the batch studies.     

Adsorption of volatile aroma compound 2-phenylethanol from synthetic solution onto granular activated carbon in batch and continuous modes

This paper reports a study on the adsorption of the aroma component 2-phenylethanol from an aqueous solution onto granular activated carbon, derived from coconut husks, using batch and continuous (packed-bed column) systems. In the batch mode, the contact time required to attain the adsorption equilibrium was 90 min. The adsorption isotherms were evaluated at 20.0 °C, 30.0 °C and 40.0 °C. In the continuous mode, the effects of flow rate and bed length were studied. Experimental data showed that the breakthrough and exhaustion times decreased with higher flow rates and increased with higher packed beds. The adsorption in the fixed-bed column was more efficient under the following conditions: flow rate of 3.5 mL min⁻¹ and bed length of 11 cm. Based on the data acquired, adsorption appears to represent a promising method for the recovery of 2-phenylethanol lost during the instant coffee production process.     

Impact of natural organic matter on monochloramine reduction by granular activated carbon: the role of porosity and electrostatic surface properties

Steady-state monochloramine reduction in fixed-bed reactors (FBRs) was quantified on five types of granular activated carbon (GAC) using two background waters-one natural source water (LAW) containing 2.5-3.5 mg/L organic carbon and one synthetic organic-free water (NW). While more monochloramine was reduced at steady-state using NW compared to LAW for each GAC and empty-bed contact time studied, the differences in removal varied considerably among the GACs tested. Physical characterization of the GACs suggested that the degree of interference caused by natural organic matter (NOM) increased with increasing GAC surface area contained within pores greater than 2 nm in width. Acid/base and electrostatic properties of the GACs were not found to be significant in terms of NOM uptake, which indicated that size exclusion effects of the GAC pores overwhelmed the impact of the GAC surface chemistry. Therefore, selection of GAC to limit the impact of NOM on monochloramine reduction in FBRs should be based on pore size distribution alone, with the impact of NOM decreasing with decreasing mesoporosity and macroporosity.     

Roles of sulfuric acid in elemental mercury removal by activated carbon and sulfur-impregnated activated carbon

This work addresses the discrepancy in the literature regarding the effects of sulfuric acid (H(2)SO(4)) on elemental Hg uptake by activated carbon (AC). H(2)SO(4) in AC substantially increased Hg uptake by absorption particularly in the presence of oxygen. Hg uptake increased with acid amount and temperature exceeding 500 mg-Hg/g-AC after 3 days at 200 °C with AC treated with 20% H(2)SO(4). In the absence of other strong oxidizers, oxygen was able to oxidize Hg. Upon oxidation, Hg was more readily soluble in the acid, greatly enhancing its uptake by acid-treated AC. Without O(2), S(VI) in H(2)SO(4) was able to oxidize Hg, thus making it soluble in H(2)SO(4). Consequently, the presence of a bulk H(2)SO(4) phase within AC pores resulted in an orders of magnitude increase in Hg uptake capacity. However, the bulk H(2)SO(4) phase lowered the AC pore volume and could block the access to the active surface sites and potentially hinder Hg uptake kinetics. AC treated with SO(2) at 700 °C exhibited a much faster rate of Hg uptake attributed to sulfur functional groups enhancing adsorption kinetics. SO(2)-treated carbon maintained its fast uptake kinetics even after impregnation by 20% H(2)SO(4).