scholarly journals Sustainable Chromium Recovery From Wastewater Using Mango and Jackfruit Seed Kernel Bio-Adsorbents

2021 ◽  
Vol 12 ◽  
Author(s):  
Deen Dayal Giri ◽  
Maulin Shah ◽  
Neha Srivastava ◽  
Abeer Hashem ◽  
Elsayed Fathi Abd_Allah ◽  
...  

Wastewater is a rich source of valuable chemicals of industrial importance. However, their economic recovery is crucial for sustainability. The objective of the present work is to recover hexavalent chromium (Cr VI) as a value-added transition metal from wastewater cost-effectively; the biosorbent derived from seed kernels of mango (M) and jackfruit (JF) were applied for removing the metal from simulated wastewater. The functional groups of the biomass were analysed with the help of Fourier transform infrared (FTIR) spectroscopy, micrographs were generated using a scanning electron microscope, and crystallinity was determined by an x-ray diffractometer (XRD). The concentration of Cr VI in wastewater was analysed by an inductively coupled plasma optical emission spectrometer (ICP-OES). Process parameters (pH, dose, contact time, temperature, and initial concentration) were optimized for efficient Cr VI adsorption using a response surface methodology-based Box–Behnken design (BBD) employing Design-software 6.0.8. The batch experiment at room temperature at pH 4.8 and Cr VI removal ∼94% (M) and ∼92% (JF) was achieved by using a 60-mg dose and an initial Cr (VI) concentration of 2 ppm in 120 min. The equilibrium Cr binding on the biosorbent was well explained using Freundlich isotherm (R2 = 0.97), which indicated the indirect interactions between Cr (VI) and the biosorbent. Biosorption of Cr (VI) followed the pseudo-order and intra-particle diffusion models. The maximum adsorption capacity of the M and JF bio-adsorbent is 517.24 and 207.6 g/mg, respectively. These efficient, cost-effective, and eco-friendly biosorbents could be potentially applied for removing toxic Cr (VI) from polluted water.

2019 ◽  
Vol 20 (7) ◽  
pp. 1567 ◽  
Author(s):  
Joanna Kluczka ◽  
Gabriela Dudek ◽  
Alicja Kazek-Kęsik ◽  
Małgorzata Gnus

In this study, a chitosan hydrogel supported with ceria (labelled Ce-CTS) was prepared by an encapsulation technique and used for the efficient removal of excess B(III) from aqueous solutions. The functionalisation of chitosan with Ce(IV) and the improvement in the adsorptive behaviour of the hydrogel were determined by SEM-EDS, FTIR, XRD, and inductively coupled plasma optical emission spectrometer (ICP-OES) analyses and discussed. The results demonstrate that Ce-CTS removes boric acid from aqueous solutions more efficiently than either cerium dioxide hydrate or raw chitosan beads, the precursors of the Ce-CTS biosorbent. The maximum adsorption capacity of 13.5 ± 0.9 mg/g was achieved at pH 7 after 24 h. The equilibrium data of boron adsorption on Ce-CTS fitted the Freundlich isotherm model, while the kinetic data followed the Elovich pseudo-second-order model, which indicated that the process was non-homogeneous. The dominant mechanism of removal was the reaction between boric acid molecules and hydroxyl groups bound to the ceria chelated by chitosan active centres. Due to its high efficiency in removing boron, good regeneration capacity and convenient form, Ce-CTS may be considered a promising biosorbent in water purification.


2013 ◽  
Vol 69 (5) ◽  
pp. 947-952 ◽  
Author(s):  
Zahra Razavi ◽  
Nourollah Mirghaffari ◽  
Behzad Rezaei

The raw rice husk (RRH) was used as a low cost adsorbent to remove three oil compounds with different viscosities (crude oil, engine oil and spent engine oil) from an aqueous environment. Some of the sorbent specifications were characterized using a CHNSO analyzer, Fourier transform infrared, scanning electron microscope and inductively coupled plasma spectroscopy. With decreasing RRH particles size, the oil adsorption percentage was reduced for crude, spent and engine oils from 50 to 30%, 65 to 20% and 70 to 0.01%, respectively. This was probably due to damage of the microcavities. The removal percentage by sorbent at optimized conditions was 88, 80 and 55% for engine, spent and crude oils, respectively, corresponding to their descending viscosity. The adsorption of crude and spent oils on rice husk followed the Freundlich isotherm model, while the adsorption of engine oil was fitted by the Langmuir model. The maximum adsorption capacity (qmax), calculated from the Langmuir model for the adsorption of engine oil on RRH, was 1,250 mg/g.


2021 ◽  
Author(s):  
Zuhal Yolcu ◽  
Meryem Çıtlakoğlu

Abstract A novel [Cd(maa)2(vim)2H2O]·H2O monomer complex was synthesized using methacrylic acid (maaH) and 1-vinylimidazole (vim) that are suitable ligands for polymerization with cadmium central atom. Cd(II)-IIP was prepared by precipitation polymerization technique using monomer complex, EGDMA, and AIBN as functional monomer, crosslinker, and initiator, respectively. The structure of the monomer complex was elucidated by single-crystal X-ray diffraction method. Infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA) methods were used for characterization both of the monomer complex and Cd(II)-IIP. Scanning electron microscopy / energy-dispersive X-ray spectroscopy (SEM/EDX) methods were used for observation surface morphology and content of the polymer surfaces. The adsorption performance and selectivity properties of Cd(II)-IIP were also investigated. The maximum adsorption capacity of Cd(II)-IIP was 43.0 mg/g with 250 mg/L initial Cd(II) concentration at pH:6.0, and the selectivity was higher for Cd2+ ions than that of Pb2+, Ni2+, and Zn2+ as competitor ions. The Langmuir and Freundlich isotherm models were applied comparatively to experimental results. Cd(II) ion content of the solutions determined by inductively coupled plasma mass spectrometry (ICP-MS).


2019 ◽  
Vol 54 (1) ◽  
pp. 31-38
Author(s):  
SS Reena ◽  
SMZ Shamshuddin ◽  
VT Vasantha ◽  
JQ D’Souza

Microwave assisted synthesis of ‘solketal’ over zirconia (ZrO2) and its modified forms (Mo(VI)/ZrO2, W(VI)/ZrO2 and V(V)/ZrO2) coated on honeycomb monoliths is reported. The solid acids were coated on honeycomb monoliths by ‘dip and dry’ method and characterized for their surface acidity, crystalinity, functionality, morphology and elemental analysis by using techniques such as NH3-Temperature programmed desorption (NH3-TPD), powder X-ray diffraction (PXRD), Fourier transform-infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) and Inductively coupled plasma-optical emission spectroscopy (ICP-OES). The honeycomb monoliths coated with solid acids were employed as catalysts in the condensation of glycerol with acetone to synthesize solketal under microwave irradiation conditions. The reaction conditions such as molar ratio of the reactants (glycerol: acetone), reaction temperature, reaction time were studied to obtain highest possible yield of solketal with greater selectivity. The catalytic activity of honeycomb catalytic material was compared with the powder forms of the catalysts. 98% yield of solketal with 98% selectivity was achieved over Mo(VI)/ZrO2 coated on a honeycomb monolith in a very shorter reaction time of 8 min at 60 oC under microwave heating. These honeycomb catalytic material were found to be easily reactivable and reusable atleast for 6 reaction cycles. Hence, honeycomb catalysts were found to be efficient, economical and effective in the synthesis of value added chemical such as solketal. A possible mechanism for the formation of solketal is proposed. Bangladesh J. Sci. Ind. Res.54(1), 31-38, 2019


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