Adsorption of diazo dye direct red-28 and tetra-azo dye direct black-22 using calcined kaolin in aqueous solutions

IF 1.3 4区化学 Q3 CHEMISTRY, MULTIDISCIPLINARY Bulletin of the Chemical Society of Ethiopia Pub Date : 2023-03-06 DOI:10.4314/bcse.v37i3.5

S. Fındık

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引用次数: 1

Abstract

ABSTRACT. In this study, the removal of diazo and tetra-azo dyes using calcined kaolin were compared. Direct red-28 (DR-28) and Direct black-22 (DB-22) was chosen as diazo and tetra-azo dyes, respectively. The kaolin obtained from Turkiye and calcined at 200 °C was found to be the most efficient adsorbent. Natural and calcined kaolins were characterized using SEM-EDS, FTIR, TGA, and XRD. The parameters such as, calcination temperature of the kaolin, adsorbent amount, temperature, initial pH, contact time, and initial concentration were studied. It was found that the removal rate of DR-28 was higher than that of DB-22 at the studied conditions. The removal of DR-28 and DB-22 were found to be 90.1% and 46.2% under the following conditions: adsorbent amount: 1.2 g/200 mL, initial concentration: 20 mg/L, original pH, temperature: 20 °C and contact time 120 min. The adsorption of the dyes was fitted to Langmuir isotherm model. The maximum adsorption capacity of calcined kaolin at 200 °C was determined as 5.39 and 3.5 mg/g for DR-28 and DB-22, respectively. The adsorption of DR-28 and DB-22 followed a pseudo-second order model. The thermodynamic study showed that the adsorption of DB-22 onto calcined kaolin was endothermic while that of DR-28 was exothermic. KEY WORDS: Adsorption, Diazo dye, Tetra-azo dye, Kaolin Bull. Chem. Soc. Ethiop. 2023, 37(3), 593-610. DOI: https://dx.doi.org/10.4314/bcse.v37i3.5

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煅烧高岭土在水溶液中吸附重偶氮染料直接红-28和四偶氮染料直接黑-22

摘要。本研究比较了煅烧高岭土对重氮和四偶氮染料的去除效果。选择直接红-28（DR-28）和直接黑-22（DB-22）分别作为重氮和四偶氮染料。从土耳其获得并在200°C下煅烧的高岭土被发现是最有效的吸附剂。利用SEM-EDS、FTIR、TGA和XRD对天然高岭土和煅烧高岭土进行了表征。研究了高岭土的煅烧温度、吸附剂用量、温度、初始pH、接触时间和初始浓度等参数。研究发现，在所研究的条件下，DR-28的去除率高于DB-22。在吸附剂用量为1.2g/200mL、初始浓度为20mg/L、初始pH、温度为20℃、接触时间为120min的条件下，DR-28和DB-22的去除率分别为90.1%和46.2%。染料的吸附符合Langmuir等温线模型。煅烧高岭土在200°C下对DR-28和DB-22的最大吸附容量分别为5.39和3.5mg/g。DR-28和DB-22的吸附遵循准二阶模型。热力学研究表明，DB-22在煅烧高岭土上的吸附是吸热的，而DR-28的吸附是放热的。关键词：吸附，二偶氮染料，四偶氮染料，高岭土。化学。Soc.Ethiop。2023,37（3），593-610.DOI:https://dx.doi.org/10.4314/bcse.v37i3.5

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来源期刊

Bulletin of the Chemical Society of Ethiopia 化学-化学综合

CiteScore

2.20

自引率

8.30%

发文量

113

审稿时长

6-12 weeks

期刊介绍： The Bulletin of the Chemical Society of Ethiopia (BCSE) is a triannual publication of the Chemical Society of Ethiopia. The BCSE is an open access and peer reviewed journal. The BCSE invites contributions in any field of basic and applied chemistry.