scholarly journals The Use of Tea leaves Wastes to reduce Hexavalent Chromium Concentration in industrial Waste Water by Adsorption

2014 ◽  
Vol 11 (2) ◽  
pp. 1067-1073
Author(s):  
Baghdad Science Journal

Abstract : A research was conducted to study the process parameters affecting hexavalent chromium Cr (VI) (carcinogenic compound) the removal percentage from the electrical industries company waste water that contain 88 mg/l of Cr (VI) concentration by adsorption onto tea wastes. Synthetic water with 88 mg/l Cr (VI) concentration was used. Several operation parameters affecting Cr (VI) removal efficiency were investigated, such as pH, initial Cr (VI) concentration, stirring time and tea wastes dose. The experimental results reveal that maximum Cr (VI) removal reached up to 94.26% at pH of 2, stirring time of 180 minute, tea wastes dose of 8gm/100 ml and the equilibrium was attained at 180 minute. Langmuir and Freundlich adsorption isotherm models were analyzed and the experimental results fit very well with Freundlich model.

2019 ◽  
Vol 79 (4) ◽  
pp. 688-698
Author(s):  
Şerife Parlayıcı ◽  
Kübra Tuna ◽  
Elif Özdemir ◽  
Erol Pehlivan

Abstract This study evaluates the application of Cr(VI) adsorption from the prepared synthetic solution by black sesame (Sesamum indicum L.) seed pulp (BSSP) and chitosan (Cts)-coated black sesame seed pulp beads (Cts-BSSP). BSSP and Cts-BSSP were used as an adsorbent without any chemical or physical treatment to remove Cr(VI) from an aqueous medium. The results indicated that the Cr(VI) removal was pH-dependent and reached an optimum at pH 2.0. It has been observed that the percentage of adsorption increased from 62% to 95% when the amount of Cts-BSSP increased from 0.0125 g to 0.0250 g. The required adsorbent amount for the maximum removal was 0.05 g and 0.1 g for Cst-BSSP and BSSP, respectively. The contact time for the adsorption was 120 min and 90 min for BSSP and Cst-BSSP, respectively. Scanning electron microscopy and Fourier transform infrared spectroscopy were used to explore the possible adsorption mechanism for Cr(VI). The equilibrium data for the BSSP and Cts-BSSP were used with the Langmuir and Freundlich adsorption isotherm models to assess the adsorption capacity and relevant mechanism. The adsorption capacity of the Cts-BSSP for Cr(VI) is relatively high compared to BSSP. The monolayer maximum adsorption capacities for Cr(VI) ions were 31.44 and 18.32 mg/g for Cts-BSSP and BSSP, respectively.


2016 ◽  
Vol 74 (10) ◽  
pp. 2305-2313 ◽  
Author(s):  
Majid Riahi Samani ◽  
Parisa Ebrahimbabaie ◽  
Hamed Vafaei Molamahmood

Over the past few years, heavy metals have been proved to be one of the most important contaminants in industrial wastewater. Chromium is one of these heavy metals, which is being utilized in several industries such as textile, finishing and leather industries. Since hexavalent chromium is highly toxic to human health, removal of it from the wastewater is essential for human safety. One of the techniques for removing chromium (VI) is the use of different adsorbents such as polyaniline. In this study, composites of polyaniline (PANi) were synthesized with various amounts of polyvinyl alcohol (PVA). The results showed that PANi/PVA removed around 76% of chromium at a pH of 6.5; the PVA has altered the morphology of the composites and increased the removal efficiency. Additionally, synthesis of 20 mg/L of PVA by PANi composite showed the best removal efficiency, and the optimal stirring time was calculated as 30 minutes. Moreover, the chromium removal efficiency was increased by decreasing the pH, initial chromium concentration and increasing stirring time.


2016 ◽  
Vol 74 (1) ◽  
pp. 236-245 ◽  
Author(s):  
Narges Samadani Langeroodi ◽  
Elaheh Safaei

The objective of this study was to investigate the use of carbonized medlar-core particles as a new biosorbent to remove Cu2+ from aqueous solution. Fourier transform infrared spectroscopy and scanning electron microscopy were used to characterize the biosorbent. This paper reports the effects of adsorbent dose, pH, temperature and concentration of adsorbate. Batch isotherm studies were also performed to understand the ability of the adsorbent. The adsorption behavior of the Cu2+ was studied using Langmuir and Freundlich adsorption isotherm models. The maximum adsorption capacity determined from the Langmuir adsorption equation has been found as 43.478 mg.g−1 at 298.15 K. The adsorption of Cu2+ by medlar core in carbonized form was spontaneous and endothermic. It was also found that the biosorption of Cu2+ followed second-order kinetics. Carbonized medlar-core particles showed great potential in aqueous solution due to the high adsorption capacity.


2020 ◽  
Vol 38 (9-10) ◽  
pp. 413-434
Author(s):  
Jessica Badillo-Camacho ◽  
Eulogio Orozco-Guareño ◽  
Gregorio G Carbajal-Arizaga ◽  
Ricardo Manríquez-Gonzalez ◽  
Icela D Barcelo-Quintal ◽  
...  

The discharges enriched with heavy metals, particularly Cr(VI), are a serious environmental problem. In this work, it is presented the use of biosorbents from eggshells membranes of ostrich, quail, duck and chicken; the membranes were easily prepared and studied for the removal of Cr(VI) from aqueous solutions. Maximum uptake of 1.41 mmol g−1 membrane permitted the identification of ostrich membrane as the material with the highest Cr(VI) uptake. N2 adsorption experiments permitted to classify ostrich membranes as mesoporous materials, since they had pore size of 14.8 nm. This represented an advantage on the nature of these membranes to be used as biosorbents with respect to other membranes. The adsorption isotherm models such as Langmuir and Freundlich were verified using experimental data. Langmuir model described the adsorption process satisfactorily at pH 1 and 2 whereas Freundlich model fitted data better at pH 3 and 5. The adsorption kinetic data were adjusted to a pseudo-second order kinetic model. TGA results permitted demonstrating a low thermal stability of ostrich membrane, since it starts decomposing at around 50°C due to the fact that membranes have about 60% protein. Through SEM microscopy was possible to observe the morphology of the membrane surfaces before and after Cr(VI) uptake which reflects the textural characteristics of the biosorbent. FTIR and XPS analyses suggested that Cr was adsorbed on ostrich membranes through the amine groups of proteins conforming the fibers of membranes. Despite the oxygen shows higher electronegativity than N, Cr shows more preference toward N due to fact that pH conditions favor the positive charges on the surface of the membrane. Our results make evident that this waste material is a novel and efficient option for the removal of Cr(VI) from aqueous solutions.


2021 ◽  
Author(s):  
CI Chemistry International

In view of promising adsorption efficiency of clay based materials, a modified iron-kaolin clay was used as an adsorbent of Pb(II) and Cd(II) ions from aqueous solutions. The effects of various experimental parameters, such as initial metal ions concentration, contact time, temperature and pH were investigated. The Langmuir and Freundlich adsorption isotherm models were applied to the experimental equilibrium data at different temperatures. The maximum adsorption capacities of Pb(II) and Cd(II) ions were 76.92 and 75.19 (mg/g), respectively. Thermodynamic parameters such as the change of Gibbs free energy, enthalpy and entropy of adsorption were also calculated and it was found that the lead and cadmium ions uptake by modified kaolin clay is endothermic and spontaneous in nature.


2020 ◽  
Vol 20 (1) ◽  
pp. 6
Author(s):  
Audy D Wuntu ◽  
Harry S.J Koleangan ◽  
Norrytha L Wuntu

Adsorpsi Metilen Biru Pada Hidroksiapatit Dari Tulang Ikan Kakap MerahABSTRAKPenelitian yang bertujuan untuk mempelajari adsorpsi metilen biru pada hidroksiapatit yang diperoleh dari tulang ikan kakap merah (Lutjanus sp.) telah dilakukan. Tulang dikalsinasi dalam tanur pada 600, 800, dan 1000 oC, digerus, dan diayak dengan ayakan 100 mesh. Material tersebut selanjutnya digunakan dalam eksperimen adsorpsi dan data yang diperoleh dianalisis menggunakan model isoterm adsorpsi Langmuir, Freundlich, dan Dubinin-Raduskevich. Hasil penelitian menunjukkan bahwa semakin tinggi suhu kalsinasi, semakin rendah kapasitas adsorben untuk mengadsorpsi metilen biru. Energi adsorpsi yang dihitung berada dalam kisaran 0,84-1,14 kJ mol-1 yang mengindikasikan bahwa metilen biru teradsorpsi secara fisik pada adsorben dan adsorpsi cenderung mengikuti model isoterm adsorpsi Freundlich.Kata kunci: kakap merah, hidroksiapatit, metilen biru, adsorpsi Adsorption of Methylene Blue on Hydroxyapatite from Red Snapper Fish Bones ABSTRACTA research aimed to study the adsorption of methylene blue on hydroxyapatite obtained from red snapper fish bones (Lutjanus sp.) was performed. The bones were calcined in a furnace at 600, 800, and 1000 oC and ground to pass a 100 mesh sieve. The materials were used in the adsorption experiment and the data obtained were analyzed using Langmuir, Freundlich, and Dubinin-Raduskevich adsorption isotherm models. The results showed that the higher the calcination temperature, the lower the capacity of the adsorbent to adsorb methylene blue. Calculated adsorption energy which was in a range of 0.84-1.14 kJ mol-1 indicated that the dye was adsorbed physically on the adsorbent and the adsorption could be well described by Freundlich adsorption isotherm model.Keywords: red snapper, hydroxyapatite, methylene blue, adsorption


2021 ◽  
Vol 13 (13) ◽  
pp. 7230
Author(s):  
Sokkeang Be ◽  
Soydoa Vinitnantharat ◽  
Anawat Pinisakul

Mangrove biochar residue was used for nitrogen adsorption and retention in sediment, which is beneficial for plant germination. The present study investigated the effect of contact time (5–360 min), biochar dosage (0.2–2 g L−1), pH (5–6), and initial concentration (2–10 mg L−1) on NH4+-N and NO3−-N adsorption. Three different adsorption isotherm models were used to fit the experimental data. Column leaching experiments were conducted to investigate the effect of biochar with sediment from a shrimp pond on nitrogen leaching at varying biochar dosages (0–8% w/w). The results showed that the maximum percentage of both NH4+-N and NO3−-N adsorption was achieved at an equilibrium contact time of 240 min, with an adsorbent dosage of 2 g L−1, and pH at 5.5 and 5, respectively. The adsorption of NH4+-N and NO3−-N were fitted to the Freundlich model and the adsorption process followed the physisorption and ion exchange. The addition of 8% biochar reduced both cumulative water volume and nitrogen leaching from the sediment. The biochar amendment increased the relative abundance of nitrifying and denitrifying bacteria in the sediment. This result suggested that biochar amended with sediment could be useful for nitrogen loss reduction.


2014 ◽  
Vol 16 (4) ◽  
pp. 597-608 ◽  

<div> <p>Removal of Fe(II) and Mn(II) ions from aqueous solution by fungal biosorbent <em>Aspergillus sp. TU-GM14</em>immobilized on <em>Detarium microcarpum</em> matrix was investigated in this study. Effects of biosorption parameters pH, biosorbent concentration, bead size and equilibrium time on Fe(II) and Mn(II) ions sorption were also determined. Equilibrium was attained within in 3 hours while optimum Fe(II) and Mn(II) ions removal was observed at pH 6, 8 mm bead size, 2 g l<sup>-1</sup> spore load respectively. Adsorption capacity was described using Langmuir, Freundlich and BET isotherm models. The experimental data fitted best to the Freundlich model (<em>R</em><sup>2</sup> 0.992 and 0.996 for Mn(II) and Fe(II) respectively). Favourable surface sorption process was described by Langmuir isotherm for both metals (<em>Q</em><sub>max </sub>34 and 14 mg g<sup>-1</sup> for Mn(II) and Fe(II) ions) while the BET isotherm constant, <em>B</em>, described high metals sorption beyond the biosorbent surface in a multi-layer sorption process (4.8 and 9.0 for Mn(II) and Fe(II)&nbsp; respectively). Results of the study showed that <em>Aspergillus sp. TU-GM14 </em>biosorbent can remove large quantities of Fe(II) and Mn(II) ions from solution in both surface and multi-layer sorption process with <em>Detarium microcarpum</em> acting as a cheap immobilization matrix.</p> </div> <p>&nbsp;</p>


Separations ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 32 ◽  
Author(s):  
Changgil Son ◽  
Wonyeol An ◽  
Geonhee Lee ◽  
Inho Jeong ◽  
Yong-Gu Lee ◽  
...  

This study has evaluated the removal efficiencies of phosphate ions (PO43−) using pristine (TB) and chemical-activated tangerine peel biochars. The adsorption kinetics and isotherm presented that the enhanced physicochemical properties of TB surface through the chemical activation with CaCl2 (CTB) and FeCl3 (FTB) were helpful in the adsorption capacities of PO43− (equilibrium adsorption capacity: FTB (1.655 mg g−1) > CTB (0.354 mg g−1) > TB (0.104 mg g−1)). The adsorption kinetics results revealed that PO43− removal by TB, CTB, and FTB was well fitted with the pseudo-second-order model (R2 = 0.999) than the pseudo-first-order model (R2 ≥ 0.929). The adsorption isotherm models showed that the Freundlich equation was suitable for PO43− removal by TB (R2 = 0.975) and CTB (R2 = 0.955). In contrast, the Langmuir equation was proper for PO43− removal by FTB (R2 = 0.987). The PO43− removal efficiency of CTB and FTB decreased with the ionic strength increased due to the compression of the electrical double layer on the CTB and FTB surfaces. Besides, the PO43− adsorptions by TB, CTB, and FTB were spontaneous endothermic reactions. These findings demonstrated FTB was the most promising method for removing PO43− in waters.


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