scholarly journals Cationic and Anionic Dye Adsorption on a Natural Clayey Composite

2021 ◽  
Vol 11 (11) ◽  
pp. 5127
Author(s):  
Carmen Omaira Márquez ◽  
Víctor Julio García ◽  
Jefferson Raúl Guaypatin ◽  
Francisco Fernández-Martínez ◽  
Anita Cecilia Ríos

One of the main challenges for environmental sciences today is the effective treatment of dye-laden industrial effluents. This work aimed to study the potential of an untreated (natural occurring clayey composite) red clay (RC) for the adsorption of a cationic dye Basic Navy Blue 2RN (CNB) and anionic dye Drimaren Yellow CL-2R (ADY). We evaluated the effect of pH, dye concentration, and adsorbent concentration on the removal effectiveness to study the absorption process. Also, we studied the adsorption process by analyzing the feasibility of several known adsorption isotherms and kinetic models. The results show that at a pH of less than 4, the CNB and ADY removal percentages were 97% and 96%, respectively. At a pH greater than 8, the CNB and ADY removals were 75% and 25%, respectively. The CNB adsorption happened by chemisorption of a monolayer on iron-containing particles (IPs). In congtrast, the ADY adsorption occurred by monolayer physisorption on kaolinite particles (KPs) and Na, K-rich Laumontite particles (LPs). The Langmuir isotherm model fits very well with CNB experimental data. The Temkin model shows the best fit between the isotherm function and the ADY dye-adsorption data. The pseudo-second-order kinetic model fits the CNB and ADY dye-adsorption data on RC particles. The heterogeneous composition of naturally occurring clay favors different adsorption mechanisms and opens an avenue for the separation process’s engineering.

2019 ◽  
Author(s):  
Chem Int

An easy route for preparation emulsion of kaolinite (Al2Si2O5.4H2O) from Sweileh sand deposits, west Amman, Jordan by hydrochloric acid under continuous stirring for 4 h at room temperature was performed and nano kaolinite powder was used as an adsorbent for the removal of Cu(II), Zn(II) and Ni(II) ions. Nano kaolinite was characterized by XRD, FT-IR and SEM techniques. Effect of pH, adsorbent dose, initial metal ion concentration, contact time and temperature on adsorption process was examined. The negative values of ΔGo and the positive value of ΔHo revealed that the adsorption process was spontaneous and endothermic. The Langmuir isotherm model fitted well to metal ions adsorption data and the adsorption capacity. The kinetic data provided the best correlation of the adsorption with pseudo-second order kinetic model. In view of promising efficiency, the nano kaolinite can be employed for heavy metal ions adsorption.


2016 ◽  
Vol 75 (4) ◽  
pp. 753-764 ◽  
Author(s):  
Asma Ehsan ◽  
Haq Nawaz Bhatti ◽  
Munawar Iqbal ◽  
Saima Noreen

Environmental applications of composites have attracted the interests of researchers due to their excellent adsorption efficiency for pollutants. Native, HCl pre-treated clay and MnFe2O4/clay composite were investigated as an adsorbent for removal of methyl green from aqueous solution. The adsorption behaviors of dye onto native, HCl pre-treated and composite clays were studied as a function of contact time, adsorbent dose, pH, initial dye concentration and temperature. Maximum dye adsorption of 44 mg/g was achieved at pH of 8, contact time 40 min, adsorbent dose 0.20 g/L and initial dye concentration of 125 mg/L using clay composite. The Langmuir isotherm and pseudo-second-order kinetic model best explained the methyl green dye adsorption onto clay adsorbents. Thermodynamic parameters revealed the endothermic and spontaneous adsorption nature of dye. From results, it is concluded that clay has potential for adsorbing methyl green and can be used for the removal of dyes from industrial effluents.


2021 ◽  
Author(s):  
Zhiyu Huang ◽  
Peng Wu ◽  
Yankun Yin ◽  
Xiang Zhou ◽  
Lu Fu ◽  
...  

Abstract In order to prepare low-cost and environmentally friendly adsorbent materials for adsorption of heavy metal ion, two kinds of novel modified cottons (C-4-APD and C-2-APZ) were obtained by introducing 4-aminopyridin and 2-aminopyrazine into the surface of degreasing cotton, respectively, and used for the removal of Cr(VI) ions from aqueous solution. The two modified cottons were characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS), which confirmed the amino groups, pyridine groups and pyrazine groups grafted onto the surface of modified cottons. The maximum adsorption capacities of C-4-APD and C-2-APZ were 73.78 mg/g and 61.34 mg/g, respectively, at the optimum pH of 6 and an initial concentration of 200 mg/g. Kinetic and isotherm studies were carried out to investigate the adsorption behavior of the modified cottons on Cr(VI) ions. The results showed that the adsorption of Cr(VI) ions by modified cottons followed a pseudo-second-order kinetic model, the equilibrium data were in good agreement with the Langmuir isotherm model, and electrostatic and chemisorption may be the main adsorption mechanisms. The recovery and reuse of modified cotton were achieved by washing with 2 wt% thiourea-hydrochloric acid solution (0.5 mol/L concentration of HCl), and the adsorption capacities of C-4-APD and C-2-APZ were maintained above 90% and 80%, respectively, after six cycles.


Author(s):  
Ali Soltani ◽  
Mehdi Faramarzi ◽  
Seyed Aboutaleb ◽  
Mousavi Parsa

Abstract Industrial effluents are usually one of the major industries polluting the environment and surface water. It is estimated that the worldwide production of dyes is about 70 tons/year. To overcome this problem, innovative processes are suggested for the treatment of industrial effluents containing dyes and heavy metals. The goal of the processes is often to reduce the toxicity of these pollutants in order to meet treatment standards. Recently, great attention has been paid to innovative processes for physical and chemical removal techniques such as adsorption on new adsorbents, biomass adsorption, membrane filtration, irradiation, and electrochemical coagulation. In this study, the application of adsorbents in the adsorption process to remove dye pollutants from industrial effluents has been studied. Factors affecting dye adsorption such as pH, temperature, initial dye concentration, and adsorbent amount are also presented. The obtained results revealed that more than 80% of the dye adsorption on the surface of adsorbents are endothermic processes and more than 95% of the processes obey the pseudo-second-order kinetic model.


2019 ◽  
Vol 9 (8) ◽  
Author(s):  
Olugbenga Solomon Bello ◽  
Kayode Adesina Adegoke ◽  
Samuel Oluwaseun Fagbenro ◽  
Olasunkanmi Seun Lameed

Abstract This study investigates the efficacy of acid activated coconut husk (CHA) for the removal of rhodamine-B (Rh-B) dye from aqueous solutions. The CHA prepared was characterized using various techniques: SEM, FTIR EDX, Boehm titration and pHpzc, respectively. The effects of different operational parameters including initial concentration, contact time and solution temperatures were examined. Kinetic data for Rh-B dye adsorption onto CHA fitted best to pseudo-second-order kinetic model considering the correlation regression (R2) and the sum of squares of error values. Adsorption data were fitted to Langmuir, Freundlich, Dubinin–Radushkevich and Temkin isotherm models. Langmuir isotherm was the most fitted among all the models used with maximum monolayer sorption capacity of 1666.67 mg g−1 and the highest regression value of 0.99 indicating that CHA has greater affinity for Rh-B dye adsorption due to increased pore development via acid activation. Thermodynamic studies revealed an endothermic adsorption process with the ΔH0 value of 62.77 kJ mol−1. Spontaneity was ascertained based on the negative values of ΔGo (ranging from − 26.38 kJ mol−1 to − 20.93 kJ mol−1). The positive value of ΔS0 (0.276 kJ mol−1 K−1) suggests increased randomness that exists between CHA and Rh-B dye. Cost analysis results revealed that CHA is six times cheaper than commercial activated carbon (CAC), providing a savings of 217 US$ kg−1. CHA adsorbent was found to be suitable for Rh-B dye removal from aqueous solution.


2002 ◽  
Vol 2 (5-6) ◽  
pp. 217-224 ◽  
Author(s):  
Z. Reddad ◽  
C. Gérente ◽  
Y. Andrès ◽  
P. Le Cloirec

In the present work, sugar beet pulp, a common waste from the sugar refining industry, was studied in the removal of metal ions from aqueous solutions. The ability of this cheap biopolymer to sorb several metals namely Pb2+, Cu2+, Zn2+, Cd2+ and Ni2+ in aqueous solutions was investigated. The metal fixation capacities of the sorbent were determined according to operating conditions and the fixation mechanisms were identified. The biopolymer has shown high elimination rates and interesting metal fixation capacities. A pseudo-second-order kinetic model was tested to investigate the adsorption mechanisms. The kinetic parameters of the model were calculated and discussed. For 8 × 10-4 M initial metal concentration, the initial sorption rates (v0) ranged from 0.063 mmol.g-1.min-1 for Pb2+ to 0.275 mmol.g-1.min-1 for Ni2+ ions, with the order: Ni2+ > Cd2+ > Zn2+ > Cu2+ > Pb2+. The equilibrium data fitted well with the Langmuir model and showed the following affinity order of the material: Pb2+ > Cu2+ > Zn2+ > Cd2+ > Ni2+. Then, the kinetic and equilibrium parameters calculated qm and v0 were tentatively correlated to the properties of the metals. Finally, equilibrium experiments in multimetallic systems were performed to study the competition of the fixation of Pb2+, Zn2+ and Ni2+ cations. In all cases, the metal fixation onto the biopolymer was found to be favourable in multicomponent systems. Based on these results, it is demonstrated that this biosorbent represents a low-cost solution for the treatment of metal-polluted wastewaters.


2020 ◽  
Vol 16 (7) ◽  
pp. 880-892
Author(s):  
Şerife Parlayıcı ◽  
Kübra Tuna Sezer ◽  
Erol Pehlivan

Background: In this work, Cr (VI) adsorption on nano-ZrO2๏TiO2 impregnated orange wood sawdust (Zr๏Ti/OWS) and nano-ZrO2๏TiO2 impregnated peach stone shell (Zr๏Ti/PSS) was investigated by applying different adsorption parameters such as Cr (VI) concentrations, contact time, adsorbent dose, and pH for all adsorbents. Methods: The adsorbents were characterized by SEM and FT-IR. The equilibrium status was achieved after 120 min of contact time and optimum pH value around 2 were determined for Cr (VI) adsorption. Adsorption data in the equilibrium is well-assembled by the Langmuir model during the adsorption process. Results: Langmuir isotherm model showed a maximum adsorption value of OWS: 21.65 mg/g and Zr๏Ti/OWS: 27.25 mg/g. The same isotherm displayed a maximum adsorption value of PSS: 17.64 mg/g, and Zr๏Ti/PSS: 31.15 mg/g. Pseudo-second-order kinetic models (R2=0.99) were found to be the best models for describing the Cr (VI) adsorption reactions. Conclusıon: Thermodynamic parameters such as changes in ΔG°, ΔH°, and ΔS° have been estimated, and the process was found to be spontaneous.


2012 ◽  
Vol 11 (02) ◽  
pp. 1250019 ◽  
Author(s):  
RAJESH KUMAR ◽  
S. K. JAIN

This study was carried out to evaluate the environmental application of functionalized carbon nanotubes through the experimental removal of strontium (II) from water. The aim was to find the optimal condition for the removal of strontium from water under different conditions such as initial concentration of strontium, contact time and neutral pH. The functionalized multi wall carbon nanotubes (f-MWCNT) were characterized by FT-IR and scanning electron microscopy (SEM). The adsorption isotherms were correlated to Freundlich and Langmuir models and it was found that the adsorption data could be fitted better by Langmuir model than Freundlich one. The kinetic data shows that the adsorption describes well with the pseudo-second order kinetic model. Functionalized MWCNT can be used as good adsorbent for the removal of the strontium ions from polluted water according to results.


Marine Drugs ◽  
2018 ◽  
Vol 16 (12) ◽  
pp. 476 ◽  
Author(s):  
Shuxian Tang ◽  
Ying Zhao ◽  
Haitao Wang ◽  
Yuqiao Wang ◽  
Hexiang Zhu ◽  
...  

A polyampholytic superabsorbent polymer (PASAP), sodium alginate-g-(polyacrylic acid-co-allyltrimethylammonium chloride) (SA-g-(PAA-co-PTM)), was prepared by free-radical graft copolymerization and characterized. The polymer exhibited pH-dependent swelling behaviors with extremely high swelling ratios, and was saline tolerant. The dye adsorption properties of SA-g-(PAA-co-PTM) were investigated using methylene blue (MB) as a cationic dye model. It was found that its dye adsorption capacity was significantly affected by the TM content in PASAP and pH of dye solution. The dye adsorption kinetics and isotherm obey the pseudo-second-order kinetic model and the Langmuir isotherm model, respectively, and the adsorption process is chemisorption in nature. In addition, SA-g-(PAA-co-PTM) exhibited high MB adsorption capacities in a wide pH range and reusability in at least five adsorption-desorption cycles, indicating its great application potentials as the adsorbent for dye removals from effluents.


2021 ◽  
Vol 10 (1) ◽  
pp. 59-66
Author(s):  
Son Le Lam ◽  
Phu Nguyen Vinh ◽  
Hieu Le Trung ◽  
Tan Le Thua ◽  
Nhan Dang Thi Thanh ◽  
...  

Glucomannan/graphene oxide (GM/GO) hydrogel was synthesized by using calcium hydroxide as the crosslinker. The synthesized material was characterized by using IR, XRD, SEM, EDX and RAMAN technology. The composite hydrogel was used for removal of organic dyes from aqueous solution. The results showed that the GM/GO hydrogel had a porous structure and a high adsorption capacity toward methylene blue (MB). The pseudo-second-order kinetic model could fit the rate equation of MB adsorption onto the GM/GO hydrogel. The adsorption of MB onto GM/GO hydrogel was a spontaneous process. In addition, the equilibrium adsorption isotherm data indicated that equilibrium data were fitted to the Langmuir isotherm and the maximum dye adsorption capacity was 198,69 mg.g-1. Moreover, the hydrogel was stable and easily recovered and adsorption capacity was around 97% of the initial saturation adsorption capacity after being used five times.


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