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Ternary biopolymeric microspherers of chitosan, yeast and gelatin were prepared and characterized by FTIR spectral analysis, particle size measurements and scanning electron micrograph techniques. Static and dynamic adsorption studies of chromium ions were performed onto the surface of the prepared microspheres at fixed pH and ionic strength of the...
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... surface charge data are shown in Table 1, which clearly indicate that the native microspheres (without adsorption) bear an EMF of -54.0 and 67.0 mV as absolute and relative EMF values, respectively. The same microspheres after adsorption of Cr 6+ ions show much higher positive potential of + 92.8 and 115.0 mV for absolute and relative EMF, respectively. ...
Citations
... Biosorption efficiency (%) was calculated using the following equation: [12] E= (C i -C f /C i ) x 100 ...
In this study, the hexavalent chromium biosorption capacities of a chromium tolerant fungal strain isolated from tannery effluent (Bantala Leather Complex, Kolkata, India) and having 99.82% similarity with Aspergillus nomius, was studied. Here we discuss, the removal of chromium (VI) by Aspergillus nomius biomass and scrutinize the practicality of exploiting them for bioremediation purposes. Therefore, to optimize biosorption, we tested biosorption potentials for the different parameters like temperature, ionic strength, pH, initial metal concentration, pre-treatment agents in varying concentrations, volume, exposure time, Amount of biomass, a combination of both biomass and volume. Biosorption studies were performed and the effectiveness of Cr (VI) biosorption was compared for each parameter. It was observed that biosorption was maximum (approximately): 95% when experimented with an initial Cr (VI) concentration of 1mg/ml; 82% when sulfuric acid was used as a pretreatment agent; 98% at pH 6 in aqueous solution; 96% at a temperature of 25 0 C; 96% when 1N sulfuric acid was used; 95% for 250ml solution; 98% when the exposure time was 24 hours and 97% when 1g of fungal biomass was used in 200ml of solution.
... The equilibrium time of Cr (VI) was observed to have been obtained within 20 min. Similar trends of equilibrium time were also observed in studies conducted by Memonet al., [11] in Cr (III) removal.Results also showed that low initial concentrations of 20 mg/l indicated higher Cr (VI) removal rates than at initial concentrations of 50 mg/l. Cr (VI) uptake of 80.6 %( 1.6mg/g) and 57.3% (2.9mg/g) was attained at 20min.This Cr (VI) uptake showed similar trends to previous studies conducted using banana peels (Al-Azzawiet al., [2]; Memonet al., [11]; Memonet al., [10]). ...
... Similar trends of equilibrium time were also observed in studies conducted by Memonet al., [11] in Cr (III) removal.Results also showed that low initial concentrations of 20 mg/l indicated higher Cr (VI) removal rates than at initial concentrations of 50 mg/l. Cr (VI) uptake of 80.6 %( 1.6mg/g) and 57.3% (2.9mg/g) was attained at 20min.This Cr (VI) uptake showed similar trends to previous studies conducted using banana peels (Al-Azzawiet al., [2]; Memonet al., [11]; Memonet al., [10]). Banana peels uptake of Cr (III) of 60-79% at higher adsorbate concentrations (10-100 mg L-1) and 80-99% at lower adsorbate concentrations (0.5-8 mg L-1) have been observed (Memonet al., [11]). ...
... Cr (VI) uptake of 80.6 %( 1.6mg/g) and 57.3% (2.9mg/g) was attained at 20min.This Cr (VI) uptake showed similar trends to previous studies conducted using banana peels (Al-Azzawiet al., [2]; Memonet al., [11]; Memonet al., [10]). Banana peels uptake of Cr (III) of 60-79% at higher adsorbate concentrations (10-100 mg L-1) and 80-99% at lower adsorbate concentrations (0.5-8 mg L-1) have been observed (Memonet al., [11]). Hence, with uptake rates of 58%, banana peels is reflected as an efficient adsorbent material for the removal Cr (VI) from aqueous solution. ...
Bananas peel was used as an adsorbent to determine its feasibility for the removal of chromium (VI). Chromium heavy metal released into the environment has caused serious contamination of water and soils with significant environmental and occupational concerns. The removal of the Cr (VI) ions from aqueous solutions is investigated in this study using of banana peels as a low cost biosorbent material. Various parameters such as pH, temperature, contact time, initial metal concentration and adsorbent dosage were investigated to determine the biosorption performance. Equilibrium was attained within 60 minutes and maximum removal of 96% was achieved under the optimum conditions at pH 2. The adsorption phenomenon demonstrated here was monolayer represented by Langmuir isotherm with R 2 value of 0.99 and the Langmuir constants k and q m was found to be 1,53 (L/mg) and 10,09 (mg/g). The adsorption system obeyed Pseudo second order kinetics with R 2 value of 0.999.
... The uptake of Cr(VI) increased as the pH of the solution is decreased as shown in Fig. 8 [34]. The relative concentration of oxy anion present in solution depends upon pH and concentration of the Cr (VI) present in solution. ...
Nano ferrite bentonite clay composite (NFBC) of magnesium ferrite nanoparticles (MgFe2O4 NPs) and bentonite is synthesized by sol-gel method and characterized by employing transmission electron microscope (TEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), FT-IR spectroscopy and BET analysis. NFBC displayed higher porosity and surface area as compared to the pristine MgFe2O4 NPs. We explored the effectiveness of NFBC for the removal of Cr (VI) from aqueous solution and the results were compared with the pristine MgFe2O4 NPs. Adsorption data was modelled using Langmuir, Freudlich and Tempkin isotherms. NFBC displayed higher Qm value along with advantageous magnetic properties of MgFe2O4 NPs. Cr (VI) loaded NFBC could be easily regenerated by washing with 0.1 N NaOH and magnetically separated from the solution. Moreover the adsorption effectiveness of 100% was maintained after five adsorption-desorption cycles.
... Most bands shifted to higher frequencies suggesting that the biomass Figure 2. FTIR spectra for COTPW, COTPW-1 and COTPW-2. [30] 2933 2934 2938 Aliphatic groups, C-H stretching in methyl and methylene group [31] 16491662 Carboxylates groups [32] 1616Amide I [33] 1508 1508 1511 Aromatic skeleton, lignin [34] 1459 1461 1465 Carboxylate groups,-OH phenolic groups [25,26] 1423 1426 1429 Carboxyl groups [35] 13351336 Carboxylate [36] 1268 1270 1272 Ester (C-O-C) [32] 1233 1234 1237 Carboxyl groups [37] 1161 C-O-C polysaccharides [34] 1125 1131 1136 Aromatic ethers [38] treatments with basic solutions led to the formation of carboxyl (-COOH), carboxylate (-COOH) and alcoholic groups (-OH). The new peaks appeared in COTPW-1 at 1616 cm −1 and in COTPW-2 at 1161 cm −1 , attributed to amide I and polysaccharides, respectively. ...
Compost derived from olive tree pruning waste (COTPW) was modified with 0.1 M (COTPW-1) and 1 M (COTPW-2) NaOH. The two biosorbents were tested for their ability to remove Pb2+ and Ni2+ ions from aqueous solutions. The effects of contact time, initial heavy metal concentration and solution temperature on the removal efficiency of COTPW-1 and COTPW-2 were also investigated. Among the two biosorbents, COTPW-1 showed a higher cation-exchange capacity (COTPW-1 = 130.4 cmolc/kg, COTPW-2 = 119.5 cmolc/kg) and lower % biomass loss due to the alkali treatment (COTPW-1 = 39.16, COTPW-2 = 60.6). Maximum Pb2+ and Ni2+ biosorptions at pH 5 and 25°C was 357.14 and 172.41 mg/g for COTPW-1, whereas for COTPW-2 they were 294.12 and 147.06 mg/g, respectively. The equilibrium adsorption data fitted well with the Langmuir isotherm and the pseudo-second-order model. Slightly reduced removal of Ni2+ from the solutions was observed in the presence of Pb2+, but Pb2+ removal was not affected by the presence of Ni2+ in the solutions. About 0.1 N HNO3 sufficiently recovered both metals from the tested materials (>95.01%). Overall, mild treatment of COTPW with NaOH greatly improved sorption characteristics.
... Beberapa teknologi pengolahan, seperti presipitasi kimia, ultra filtrasi, adsorpsi, telah diterapkan untuk penghilangan polutan logam berat. Banyak proses juga telah digunakan untuk menghilangkan logam berat terlarut, termasuk pertukaran ion, fitoekstraksi, ultrafiltrasi, reverse osmosis, dan elektrodialisis (Chmielewska, 2003;Erdem dkk.. 2004;Roto dkk., 2009;Bajpai dan Rai 2010;Hemalatha dan Prasada, 2012;Gopalakrishnan dkk., 2013). Penggunaan bahan alam yang murah sebagai adsorben alternatif untuk menghilangkan logam berat kini lebih ditekankan. ...
ABSTRAK
Kromium (VI) merupakan polutan logam berat berbahaya bagi kesehatan dan lingkungan oleh karena itu pengambilan ion Cr(VI) dalam air penting dilakukan untuk mengatasi pencemaran lingkungan. Proses adsorpsi merupakan salah satu teknik sederhana yang dapat digunakan untuk pengambilan ion logam. Pada penelitian ini telah dilakukan kajian adsorpsi ion dikromat sebagai model limbah Cr(VI) dalam air menggunakan adsorben zeolit alam termodifikasi amina. Penelitian diawali dengan preparasi adsorben zeolit alam termodifikasi amina. Preparasi dimulai dengan pencucian zeolit alam menggunakan akuades, kemudian refluks zeolit alam menggunakan HCl 3M. Zeolit hasil refluks selanjutnya dimodifikasi menggunakan garam ammonium kuarterner, N-cethyl-N,N,N-trimethylammonium bromide (CTAB) dan amina primer, propilamin (PA). Zeolit alam (Z), zeolit teraktivasi asam (ZA) dan zeolit hasil modifikasi amina selanjutnya digunakan sebagai adsorben untuk adsorpsi anion dikromat. Karakterisasi adsorben dilakukan dengan mengunakan metode spektroskopi infaramerah dan difraksi sinar-X, sedangkan jumlah anion dikromat yang teradsorpsi dianalisis dengan spektroskopi serapan atom. Hasil penelitian menunjukkan bahwa sampel zeolit mengandung mineral klinoptilolit, mordernit dan kuarsa. Struktur zeolit tidak mengalami kerusakan oleh perlakuan termal dan perlakuan kimia. Modifikasi zeolit meningkatkan efisiensi adsorpsi zeolit alam. Ion dikromat dapat teradsorpsi dengan lebih baik oleh zeolit termodifikasi amina daripada zeolit teraktivasi asam dan zeolit tanpa modifikasi, dengan kemampuan adsorpsi zeolit termodifikasi CTAB (CTAB-Z) lebih besar daripada zeolit termodifikasi propilamin (PA-Z). Adsorpsi ion dikromat pada adsorben zeolit berlangsung baik dengan urutan CTAB-Z > PA-Z > ZA > Z, dengan kemampuan adsorpsi masing-masing sebesar 1,96; 1,74; 0,90 dan 0,48 mg/g. Adsorpsi anion dikromat oleh zeolit termodifikasi CTAB merupakan adsorpsi kimia (kemisorpsi) dengan energi adsorpsi sebesar 24,66 kJ/mol.
ABSTRACT
Chromium (VI) is a heavy metal pollutant that is harmful to health and the environment, therefore Cr(VI) ions in aqueous solution removal is important to overcome the environmental pollution. Adsorption process is one of simple techniques that can be used to take metal ions. Adsorption study of dichromate ions as a wastewater model of Cr(VI) has been conducted in this research by using ammine modified natural zeolite as adsorbents. The research was initiated by preparation of adsorbent of ammine-modified natural zeolites. The preparation was started by washing the natural zeolite (Z) using distilled water and refluxing by 3M hydrochloric acid. Refluxed zeolites (ZA) were modified by a quaternary ammonium salt, N-cethyl-N,N,N-trimethylammonium bromide (CTAB), and a primary amine, propylamine (PA). The natural zeolite (Z), acid activated zeolite (ZA) and amine-modified zeolites were then applied for adsorption of dichromate ions. Characterization of zeolite samples was performed by infrared spectroscopy and X-ray diffraction methods to confirm the crystal structure, and atomic absorption spectroscopy method to analyze the adsorbed dichromate ions. Results showed that all zeolite samples contain clinoptilolite, mordernite and quartz minerals. The zeolite structure was not changed by heat and chemical treatments. Modification of zeolites enhanced the adsorption efficiency of natural zeolites. The dichromate ions were better adsorbed on ammine modified-zeolites compared to that of unmodified-zeolite with adsorption ability of CTAB modified zeolite (CTAB-Z) was greater than that of propylammine modified zeolite (PA-Z). The adsorption of dichromate on zeolite samples was achieved in the order of CTAB-Z > PA-Z > ZA > Z, with the adsorption efficiency was about 1.96; 1.74; 0.90 and 0.48 mg/g, respectively. The dichromate ions adsorption by CTAB modified zeolite is chemical adsorption (chemisorption) with the adsorption energy of 24.66 kJ/mol.
... From the Fig. 6, it is clear that with an increase in metal concentration from 20 to 100 mg/L, removal percentage decreases from 97 to 88 with an increase in adsorption capacity. The maximum removal was obtained within 15 minutes, after which there was C (Bajpai and Rai, 2010). The data generated due to effect of initial metal concentration helps in determining the equilibrium concentration(C e ), adsorption capacity(q e ), metal uptake rate and kinetic characteristics. ...
Gooseberry seed (Phyllanthus acidus) was used as an adsorbent to determine its feasibility for the removal of chromium (VI). Various parameters such as pH, temperature, contact time, initial metal concentration and adsorbent dosage were investigated to determine the biosorption performance. Equilibrium was attained within 60 minutes and maximum removal of 96% was achieved under the optimum conditions at pH 2. The adsorption phenomenon demonstrated here was monolayer represented by Langmuir isotherm with R 2 value of 0.992 and the Langmuir constants k and q 0 was found to be 0.0061 (L/mg) and 19.23 (mg/g). The adsorption system obeyed Pseudo second order kinetics with R 2 value of 0.999. The results of the present study indicated that gooseberry seed powder can be employed as adsorbent for the effective removal of hexavalent chromium economically.
... Effect of pH The uptake of Cr(VI) increased as the pH of the solution is decreased as shown inFig. 8 [34] . The relative concentration of oxy anion present in solution depends upon pH and concentration of the Cr (VI) present in solution. ...
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... However, deeper analysis of the first order plot ( Figure 5) revealed certain linearity within the first 30 min gap for both Telon-dyes, but as the process evolved in time, a loss of linearity was observed. Calculation attempts according to the pseudo-first order model 35 gave inaccurate values of the rate constant with estimated correlation coefficients (R 2 ) of 0.91 for Telon-red-Cu and 0.93 for Telon-blue-Cu (Table 1). b Estimated for the second diffusion step (intra-particle diffusion). ...
Ion-exchange of montmorillonite with para-bis(triphenyl phosphonium methylene)-benzene ions (p-TPhPMB) provided an organo-montmorillonite adsorbent with improved affinity towards Telon dyes. Adsorption tests applied to Telon-red and Telon-blue in the presence of Cu(II) cations revealed a significant increase in the maximum adsorption capacity from ca. 11-26 for the starting clay mineral to ca. 110-160 mg.g-1 after intercalation. This improvement was attributed to increases in both the organophilic character towards the organic dyestuffs investigated and the interlayers spacing. Besides dye-diphosphonium and Cu(II)-diphosphonium interactions, dye adsorption on organo-montmorillonite also involved the formation of Cu(II) exchanged Telon-dye species. It was found that dye adsorption involves not only binary interactions between the three chemical species, but also synergy due to a possible bridging action of the divalent Cu(II) cations. On organo-Mt, the organophilic character was a key factor for higher amounts of adsorbed dye.
The current investigation presents the role of gooseberry (Phyllanthus acidus) seeds as an effective biosorbent for remediating chromium(VI)), a toxic heavy metal pollutant commonly found in effluents from tanneries and relevant industries. Biosorption was affected by pH, temperature and initial metal concentration. Furthermore, there is a need to understand the holistic effect of all variables to ascertain the best possible conditions for adsorption, therefore, these factors were considered and a total of 17 trials were run according to the Box Behnken design. Quadratic model had maximum R 2 value (0.9984) and larger F value (1109.92). From the Analysis Of Variance table and R 2 value, quadratic model was predicted to be the significant model with the best fit to the generated experimental data. The optimal parameters obtained from the contour plot for the maximum removal of chromium(VI) were initial metal concentration of 60 mg/L, pH value of 2, and temperature of 27°C. Under these conditions, maximum removal of 92% was obtained. Thus this biosorbent substantially eliminates chromium(VI) under optimized conditions, enabling its use in larger scale.
Biosorption, using microbes is regarded as cost-effective technology for the treatment of metal-bearing waste waters. In recent years, several biosorbents have been investigated. In the present study, Aspergillus flavus, Chromium resistant fungal strains was isolated and morphologically characterized from the soil samples textile effluent discharged unit is used as biosorption organism. The efficacy of isolates for the biosorption of hexavalent chromium was analyzed. Effect of various parameters was assayed, which include temperature (optimized at 27°C), pH (optimized at 1), different carbon (effective with sucrose), initial metal (decreased with increasing concentration) and different biomass concentration (increases with increasing concentration). In chromium treated biosorbent, adsorption bands observed at 3430.72 cm-1, 2932.84 cm-1, 1638.72 cm-1, 1542.89 cm-1, 1155.47 cm-1 and 1047.63 cm-1. SEM image concludes over the biosorption period, the morphology of the fungus had undergone remarkable physical disintegration. The isolate has 58% biosorption capacity and released 40% biosorbed Cr(VI) ions on NaOH desorption studies.
