Environmental and Hydraulic Monitoring Using Cationic Dyes to Investigate the Barriers Effect on Kaolin Deposition (original) (raw)
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Adsorption of Cationic and Anionic Dyes onto Commercial Kaolin
Adsorption Science & Technology, 2009
Commercial kaolin from a Polish deposit has been examined as a low-cost adsorbent for effluent remediation using five cationic and five anionic industrial dyes. Methylene Blue dye was also used as a reference. The anionic dyes studied showed no affinity towards the kaolin surface, whereas the experimental isotherms for the adsorption of the cationic dyes could all be well described by the Langmuir equation. The values of the adsorption capacity of kaolin towards the cationic dyes ranged from 4 mg/g to 29 mg/g, being probably dependent on the geometry of the dye molecules. The resulting degrees of decolourization attained values of 85-90% for initial dye concentrations in the range 6-20 mg/dm 3 and for kaolin loadings of 0.5-3 g/dm 3. Adsorption of the cationic dyes onto kaolin increased at higher solution pH values.
RSC Adv., 2015
The contamination of surface water by dyes released from the effluent of textile industries is a major environmental concern. Adsorption is a cheap and easy separation technique to remove dyes from the effluent water. In this study, the adsorption behaviors of a widely used cationic dye, methylene blue (MB), on kaolinite clay surface in the presence and absence of electrolytes have been reported. The adsorption isotherms of MB in the absence of electrolytes follow the Langmuir model, however, in the presence of electrolytes they follow the Freundlich model. At a constant dye concentration (below the saturation equilibrium concentration), the dye adsorption increases linearly along with the increasing ionic strength of the electrolyte solutions. Among the four electrolytes (NaCl, CaCl 2 , Na 2 SO 4 , Na 2 HPO 4 ) studied here, Na 2 HPO 4 has the highest adsorption enhancement ability, $127% with respect to that of pure MB at a 2 mM initial concentration. This study shows that the adsorption capacity of kaolinite clay can be enhanced significantly by the use of electrolytes, which is very useful for the remediation of dye contaminated waste water.
International journal of biological and chemical sciences, 2024
Kaolin possesses unique features suitable for removing pollutants from aqueous solutions, in this regard, improving its effectiveness as an adsorbent is important. This study focused on refining the absorbance efficiency of Pugu kaolin clay from Tanzania to enhance its utilization in removing textile dyes from contaminated water. The process involved acid-activation after calcination at 750 o C. Characterization using X-ray Fluorescence (XRF), X-ray diffraction (XRD), Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR) and Porosimeter techniques revealed the presence of kaolinite [Al2Si2O5(OH)4], silica (SiO2) and microcline [KAlSi3O8] as the main phases. Acid treatment resulted in an increase in silica content from 44.18% to 58.81% due to the appearance of tridymite, while alumina decreased from 26.70% to 12.74% due to the removal of kaolinite. Surface area significantly expanded from 15.36 to 149.61 m 2 /g as acid-soluble impurities were eliminated. Chemical composition was also altered, with a decrease in Fe2O3 and increase in other major oxides. The impact of acid activation on the adsorption capacity of the clay was investigated by studying various parameters such as contact time, temperature, adsorbent dose, initial pH and adsorbate concentration. Basic Blue 9 (BB9) and Direct Red 28 (DR28) dyes were used as model adsorbates. The results obtained at optimal conditions of 3 hours contact time, 27 o C temperature, 0.9 g adsorbent dose, initial pH of 11 and initial adsorbate concentration of 90 mg/L, showed that acid modification of the clay increased its capacity to adsorb BB9 from 96.82% to 99.91%, and DR28 from 86.33% to 95.04%. These findings underscore the positive impact of modifying the raw clay, enhancing its suitability for dye removal applications.
SN Applied Sciences
Presence of dye molecules in water causes various harmful effects for both human and aquatic species. Herein, we tried to remove two cationic dyes, namely Crystal violet and Brilliant green, from water by kaolinite clay mineral. The kaolinite clay mineral is further treated with 0.25 M and 0.05 M H 2 SO 4 to increase its adsorption capacity. The structural changes due to acid treatment were analyzed by XRD, zeta potential, FTIR, SEM, cation exchange capacity, BET surface area, and pore volume measurements. Kinetic data were analyzed by using five different kinetic models and the data fitted best to pseudo-second-order model. Langmuir isotherm showed best fit to the adsorption of both Crystal violet and Brilliant green. Acid-treatment has slightly increased the adsorption capacities for both the dyes. The Langmuir monolayer adsorption capacity of raw kaolinite was found to be 47.17 and 25.70 mg g −1 for Crystal violet and Brilliant green, respectively, which increased to 49.50 and 50.51 mg g −1 for 0.25 M and 0.50 M acid-treated kaolinite in case of Crystal violet and to 26.45 and 26.88 mg g −1 in case of Brilliant green at 303 K. Crystal violet adsorption was exothermic with increase in ∆G values, whereas Brilliant green adsorption was endothermic in nature with decrease in ∆G in the temperature range 293-323 K. Reusability study showed the adsorbents could be successfully used up to 3rd cycle without much loss of adsorption capacity.
Removal of cationic dyes by kaolinite
Microporous and Mesoporous Materials, 2009
The removal of cationic dyes such as maxilon yellow 4GL (MY 4GL) and maxilon red GRL (MR GRL) on kaolinite from aqueous solutions has been studied according to the adsorption method. The adsorbed amount of dyes on kaolinite surface was investigated as a function of pH, ionic strength, temperature, acid activation, and calcination temperature. It was found that: (i) the adsorbed amount of cationic dyes increased with increase in pH and decreased with increase in temperature, ionic strength, acid activation, and calcination temperature; (ii) the adsorption process was an exothermic process; (iii) the experimental data were correlated reasonably well by the adsorption isotherm of the Langmuir; and (iv) the interactions between adsorbate and adsorbent from adsorption heat data were physical in nature.
The design of wastewater treatment methods is usually based on the need to reduce heavy metals and suspended solid loads to limit pollution of the environment. The quality of treated effluent used in agriculture has a great influence on the operation and performance of the wastewater-soil-plant or aquaculture system. In the case of irrigation, the required quality of effluent is dependent on the crops to be irrigated, the soil conditions and the system of effluent distribution adopted. The present study is aimed to provide a healthy and better environment for both man and aquatic bodies. In this study, Nsu clay was modified by thermal and alkaline process for the removal of heavy metals and organic pollutants from industrial paint effluent. The modified clay was used to purify effluent from paint industry through a process involving coagulation for colour and sorption. The treated effluents were analyzed for the heavy metal concentration such as chromium, potassium, lead, magnesium, manganese, iron, cobalt, sodium, silver, mercury and cadmium. Furthermore, some gross organic pollution indicators such as biological oxygen demand (BOD) and chemical oxygen demand (COD) as well as pH, acidity, alkalinity, turbidity, hardness and total dissolved solids (TDS) of the effluents were studied. It was found that percentage removal was over 60% for all the contaminants. The modified clay exhibited better performance when calcined at 750 o C with 4M NaOH. Application of the simple and low cost modification technique employed in this study makes kaolinite a co-effective adsorbent for removal of many organic and inorganic pollutants from industrial paint effluents. ________________________________________________________________________________________ INTRODUCTION There have been increased concerns on the level of pollution caused by waste water which contained heavy metal ions, dyes and organic substance on the environment due to their toxic nature to man, plants, animals and aquatic life. These pollutants usually get into the environment from industrial effluents as a result of rapid industrial growth in most developing nations [1]. The disposal of industrial effluents has always been a major environmental issue. Pollutants in industrial effluents are always very toxic that the effluent has to be treated before its reuse or disposal in water bodies. These heavy metals are usually non-biodegradable, persistent in nature and very toxic even at certain low concentrations [2], causing serious health hazards such as cancer, headache, liver and kidney damages when present above the threshold limit in humans. Dyes are used for coloring purposes in textile, food, paper, carpet, rubber, cosmetic and plastic industries. Over 735 tons of synthetic dyes are produced annually worldwide and during the coloring processes approximately 10–15% of them are lost to waste streams as pollutants. Some of these dyes are toxic and suspected to have carcinogenic and mutagenic effects, some present an aesthetic problem and affect the nature of water reducing photosynthetic activity by inhibiting sunlight penetration [3]. Similarly persistent organic pollutants have been known to be very detrimental to humans and animals. Paint production is one of the viable Small and Medium Scale Enterprises (SMEs) in Nigeria. Effluents from paint industries are among the problematic environmental issues faced by the Nigerian Chemical Manufacturing Sector. Paint
Dye Adsorption in a Loam Soil as Influenced by Potassium Bromide
Journal of Environment Quality, 1999
FD&C Blue #1 and Rhodamine VVT have been used in soils to trace preferential flow paths while bromide has been used to study flow paths of water or nonretarded chemicals. This study quantified the interactions of KBr, FD&C Blue #1, and Rhodamine WT on dye adsorption in Forman loam (fine-loamy, mixed Udic Argiboroll) soil.
Sorption of Synthetic Dyes Onto River Sediments: A Laboratory Study
Nova Biotechnologica et Chimica, 2013
This work deals with sorption of cationic synthetic dye thioflavine T (ThT) onto the river sediment obtained from the Váh River under conditions of batch and column system using spectrophotometric methods. We found that sorption of ThT onto river sediment was a rapid process with reaching of concentration equilibrium within 2 h of interaction. The values of distribution coefficient (DC) defined as concentration ratio [ThT] sediment : [ThT] solution were linearly increased with increasing concentration of river sediment in solution within the range C sediment 1.25 -10.0 g/dm 3 and minimally changed in the range of initial pH values 2 -6. The increasing concentration of ThT in model solution caused exponentially decrease in the value of DC. The sorption processes characterized by dependence between equilibrium specific sorption Q eq and ThT concentration C eq in solution were better described by adsorption isotherm according to Freundlich (R 2 = 0.979) than according to Langmuir adsorption isotherm (R 2 = 0.914). From evaluation of ThT sorption onto river sediment in column system containing of 5 cm sediment layer with 30 cm of water column on the basis of ThT concentration changes in infiltrated water we found that these processes were significantly dependent on the rate of infiltrated water flow through the sediment layer R iw as well as on qualitative and quantitative composition of water. The highest ThT desorption from the sediment layer was found in seepage of 50 % (v/v) ethanol (EtOH) solution through the sediment and efficiency of ThT desorption decreased in the order: 50 % (v/v) EtOH > 0.1 mol/dm 3 HCl > deionized water. Obtained data from the point of view of physico-chemical characteristics of the river sediment, such as pH, pH zpc (potentiometric titration), cation-exchange capacity (CEC) and elemental composition (X-ray fluorescence spectrometry), was also discussed.
2022
The effectiveness of thermal and acid modified locally available kaolin clay in Tanzania (Pugu clay), for removal of cationic dye from water systems were tested. The raw Pugu kaolin (RPK) was thermally-treated at 150oC for 7 hours and acid-leached with 0.2 M H2SO4 under reflux for 3 hours, to obtain thermally-activated Pugu kaolin (TAPK) and acid-activated Pugu kaolin (AAPK), respectively. The raw and modified clays were characterized by XRF, XRD, ATR-FTIR and Porosimeter for their mineralogical compositions, chemical compositions, specific surface areas and pore sizes. A comparative analysis of their respective adsorption efficiencies was carried out using basic blue 9 dye (BB9) as a representative adsorbate. The results revealed that while RPK was mainly composed of 44.18% silica and 26.70% alumina, the modified adsorbents had higher silica content of 46.95% and 58.81%; decreased alumina content of 24.11% and 12.74%, and increased surface areas from 15.36 to 41.07 m2/g and 149.61 ...