scholarly journals Batch Study of Cadmium Biosorption by Carbon Dioxide Enriched Aphanothece sp. Dried Biomass

Water ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 264 ◽  
Author(s):  
Awalina Satya ◽  
Ardiyan Harimawan ◽  
Gadis Sri Haryani ◽  
Md. Abu Hasan Johir ◽  
Saravanamuthu Vigneswaran ◽  
...  

The conventional method for cadmium removal in aqueous solutions (1–100 mg/L) is ineffective and inefficient. Therefore, a batch biosorption reactor using a local freshwater microalga (originating from an urban lake, namely, Situ Rawa Kalong-Depok) as dried biosorbent was tested. Biosorbent made from three kinds of cyanobacterium Aphanothece sp. cultivars (A0, A8, and A15) were used to eliminate cadmium (Cd2+) ions in aqueous solution (1–7 mg/L). The biosorbents were harvested from a photobioreactor system enriched with carbon dioxide gas of 0.04% (atmospheric), 8%, and 15% under continuous light illumination of about 5700–6000 lux for 14 d of cultivation. Produced dried biosorbents had Brunauer–Emmet–Teller (BET) surface area ranges of 0.571–1.846 m2/g. Biosorption of Cd2+ was pH and concentration dependent. Sorption was spontaneous (ΔG = −8.39 to −10.88 kJ/mol), exothermic (ΔH = −41.85 to −49.16 kJ/mol), and decreased randomness (ΔS = −0.102 to −0.126 kJ/mol. K) on the interface between solid and liquid phases when the process was completed. The kinetic sorption data fitted best to the pseudo-second-order model (k2 = 2.79 × 10−2, 3.96 × 10−2, and 4.54 × 10−2 g/mg.min). The dried biosorbents of A0, A8, and A15, after modeling with the Langmuir and Dubinin–Radushkevich isotherm models, indicated that cadmium binding occurred through chemisorption (qmax, D-R = 9.74 × 10−4, 4.79 × 10−3, and 9.12 × 10−3 mol/g and mean free energy of 8.45, 11.18, and 11.18 kJ/mol) on the monolayer and homogenous surface (qmax, Langmuir of 12.24, 36.90, and 60.24 mg/g). In addition, the results of SEM, EDX, and FTIR showed that there were at least nine functional groups that interacted with Cd2+ (led to bond formation) after biosorption through cation exchange mechanisms, and morphologically the surfaces changed after biosorption. Biosorbent A15 indicated the best resilient features over three cycles of sorption–desorption using 1 M HCl as the desorbing eluent. These biosorbents can be a potent and eco-friendly material for treating aqueous wastewater.

2019 ◽  
Vol 14 (31) ◽  
pp. 148-160
Author(s):  
Ashraf M. Alattar

This article will address autoclave design considerations andmanufacturing working with high pressure low temperaturesupercritical drying technique to produce silica aerogel. The designelects carbon dioxide as a supercritical fluid (31.7 oC and 72.3 bar).Both temperature and pressure have independently controllingfacility through present design. The autoclave was light weight (4.5kg) and factory-made from stainless steel. It contains a high pressurewindow for monitoring both transfer carbon dioxide gas to liquidcarbon dioxide and watching supercritical drying via aerogelpreparation process. In this work aerogel samples were prepared andthe true apparent densities, total pore volume and pore sizedistribution, BET surface area, spectroscopic refractive index,structure and thermal properties have been systematicallyinvestigated characteristic.


2020 ◽  
Vol 21 (2) ◽  
pp. 15-23
Author(s):  
Teba Hameed Mhawesh ◽  
Ziad T. Abd Ali

   The potential application of granules of brick waste (GBW) as a low-cost sorbent for removal of Ni+2ions from aqueous solutions has been studied. The properties of GBW were determined through several tests such as X-Ray diffraction (XRD), Energy dispersive X-ray (EDX), Scanning electron microscopy (SEM), and BET surface area. In batch tests, the influence of several operating parameters including contact time, initial concentration, agitation speed, and the dose of GBW was investigated. The best values of these parameters that provided maximum removal efficiency of nickel (39.4%) were 1.5 hr, 50 mg/L, 250 rpm, and 1.8 g/100mL, respectively. The adsorption data obtained by batch experiments subjected to the Three isotherm models called Langmuir, Freundlich and Elovich, The results showed that the Freundlich isotherm model described well the sorption data (R2=0.9176) in comparison with other models. The kinetic data were analyzed using two kinetic models called pseudo-first-order and pseudo-second-order. The pseudo-first-order kinetic model was found to agree well with the experimental data.  


2020 ◽  
Vol 59 (SK) ◽  
pp. SKKD08
Author(s):  
Yuya Kitamura ◽  
Hirokazu Okawa ◽  
Takahiro Kato ◽  
Katsuyasu Sugawara

2016 ◽  
Author(s):  
Ernie R. Slucher ◽  
◽  
Peter D. Warwick ◽  
Christina A. DeVera ◽  
Celeste D. Lohr ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alaa El Din Mahmoud ◽  
Khairia M. Al-Qahtani ◽  
Sahab O. Alflaij ◽  
Salma F. Al-Qahtani ◽  
Faten A. Alsamhan

AbstractEnvironmentally friendly copper oxide nanoparticles (CuO NPs) were prepared with a green synthesis route without using hazardous chemicals. Hence, the extracts of mint leaves and orange peels were utilized as reducing agents to synthesize CuO NPs-1 and CuO NPs-2, respectively. The synthesized CuO NPs nanoparticles were characterized using scanning electron microscopy (SEM), Energy Dispersive X-ray Analysis (EDX), BET surface area, Ultraviolet–Visible spectroscopy (UV–Vis), and Fourier Transform Infrared Spectroscopy (FT-IR). Various parameters of batch experiments were considered for the removal of Pb(II), Ni(II), and Cd(II) using the CuO NPs such as nanosorbent dose, contact time, pH, and initial metal concentration. The maximum uptake capacity (qm) of both CuO NPs-1 and CuO NPs-2 followed the order of Pb(II) > Ni(II) > Cd(II). The optimum qm of CuO NPs were 88.80, 54.90, and 15.60 mg g−1 for Pb(II), Ni(II), and Cd(II), respectively and occurred at sorbent dose of 0.33 g L−1 and pH of 6. Furthermore, isotherm and kinetic models were applied to fit the experimental data. Freundlich models (R2 > 0.97) and pseudo-second-order model (R2 > 0.96) were fitted well to the experimental data and the equilibrium of metal adsorption occurred within 60 min.


Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 63
Author(s):  
Maria Harja ◽  
Gabriela Buema ◽  
Nicoleta Lupu ◽  
Horia Chiriac ◽  
Dumitru Daniel Herea ◽  
...  

Fly ash/magnetite material was used for the adsorption of copper ions from synthetic wastewater. The obtained material was characterized by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET) surface area, and vibrating sample magnetometer (VSM). Batch adsorption experiments were employed in order to investigate the effects of adsorbent dose, initial Cu (II) concentration and contact time over adsorption efficiency. The experimental isotherms were modeled using Langmuir (four types of its linearization), Freundlich, Temkin, and Harkins–Jura isotherm models. The fits of the results are estimated according to the Langmuir isotherm, with a maximum adsorption capacity of 17.39 mg/g. The pseudo-second-order model was able to describe kinetic results. The data obtained throughout the study prove that this novel material represents a potential low-cost adsorbent for copper adsorption with improved adsorption capacity and magnetic separation capability compared with raw fly ash.


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