scholarly journals Recovery and Then Individual Separation of Platinum, Palladium, and Rhodium from Spent Car Catalytic Converters Using Hydrometallurgical Technique followed by Successive Precipitation Methods

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Ahmed M. Yousif
Keyword(s):  
Contact Time ◽  
Catalytic Converter ◽  
Economic Value ◽  
Hydrogen Atmosphere ◽  
Catalytic Converters ◽  
Batch Experiments ◽  
Experimental Conditions ◽  
Leaching Process ◽  
Manufactured Products ◽  
Leaching Solution

Recovery of PGMs (especially rhodium, platinum, and palladium) from different spent manufactured products (like catalytic converters) is considered as an important task as they are rarely found in nature, and they possess high economic value. In this work, the honeycomb of a car catalytic converter was primarily processed by crushing, grinding, and then treating in a hydrogen atmosphere. In order to establish an economic and ecofriendly method for the recovery of studied PGMs, different experimental conditions of changing HCl/H2O2 (as a leaching solution) ratio, temperature, and contact time were studied through batch experiments to obtain the optimum leaching conditions. The use of 0.8 vol% H2O2 and 9.0 M HCl mixture at 60°C for a contact time of 2.5 hours during the leaching process may be considered as the best conditions to be followed to save chemicals, energy, and time (about 86%, 96%, and 98% of Rh, Pt, and Pd were recovered, respectively). Individual separation of PGM ions from each other using precipitation technique from their leaching liquor was performed where % purity values of 99.5, 99.3, and 95.5 were obtained for Pt, Pd, and Rh, respectively.

scholarly journals Adsorption of brilliant green dye on Nephelium mutabile (Pulasan) leaves

2018 ◽  
Vol 17 (1) ◽  
Author(s):  
Nur Afiqah Hazirah Mohamad Zaidi ◽  
Liew Wei Jing ◽  
Linda B. L. Lim
Keyword(s):  
Experimental Data ◽  
Contact Time ◽  
Brilliant Green ◽  
Cost Effective ◽  
Point Of Zero Charge ◽  
Isotherm Models ◽  
Maximum Adsorption Capacity ◽  
Batch Experiments ◽  
Adsorption Method ◽  
Experimental Conditions

The main objective of this study is to investigate the ability of Nephelium mutabile (Pulasan) leaves (PL) in removing toxic brilliant green (BG) dye using the adsorption method. Batch experiments were conducted on the adsorption of BG dye using PL with a contact time of 3.5 h. Adsorption isotherm studies were analysed using six isotherm models, namely Langmuir, Freundlich, Temkin, Dubinin-Radushkevich (D-R), Redlich-Peterson (R-P) and Sips, and the results showed that Sips is the model that best fits the experimental data, with a maximum adsorption capacity (amax) of 130.3 mg g-1. The point of zero charge (pHPZC) of PL was found to be at pH 5.29. Regeneration studies showed that PL can be recovered and reused, especially after treatment with NaOH. This study demonstrates that PL can be considered as a reasonably good and cost-effective biosorbent for BG under our experimental conditions.

scholarly journals Recovery of Platinum from a Spent Automotive Catalyst through Chloride Leaching and Solvent Extraction

Recycling ◽  
2021 ◽  
Vol 6 (2) ◽  
pp. 27
Author(s):  
Ana Méndez ◽  
Carlos A. Nogueira ◽  
Ana Paula Paiva
Keyword(s):  
Solvent Extraction ◽  
Environmental Sustainability ◽  
Catalytic Converter ◽  
Reaction Times ◽  
Model Solution ◽  
Critical Metals ◽  
Experimental Conditions ◽  
Chloride Leaching ◽  
Good Potential ◽  
Hydrometallurgical Treatment

Considering economics and environmental sustainability, recycling of critical metals from end-of-life devices should be a priority. In this work the hydrometallurgical treatment of a spent automotive catalytic converter (SACC) using HCl with CaCl2 as a leaching medium, and solvent extraction (SX) with a thiodiglycolamide derivative, is reported. The aim was to develop a leaching scheme allowing high Pt recoveries and minimizing Al dissolution, facilitating the application of SX. The replacement of part of HCl by CaCl2 in the leaching step is viable, without compromising Pt recovery (in the range 75–85%), as found for the mixture 2 M CaCl2 + 8 M HCl when compared to 11.6 M HCl. All leaching media showed good potential to recover Ce, particularly for higher reaction times and temperatures. Regarding SX, results achieved with a model solution were promising, but SX for Pt separation from the real SACC solution did not work as expected. For the adopted experimental conditions, the tested thiodiglycolamide derivative in toluene revealed a very good loading performance for both Pt and Fe, but Fe removal and Pt stripping from the organic phases after contact with the SACC solution were not successfully accomplished. Hence, the reutilization of the organic solvent needs improvement.

scholarly journals Biosorption of Congo Red and Methylene Blue by pretreated waste Streptomyces fradiae biomass - Equilibrium, kinetic and thermodynamic studies

2018 ◽  
Vol 83 (1) ◽  
pp. 107-120 ◽  
Author(s):  
Zdravka Velkova ◽  
Gergana Kirova ◽  
Margarita Stoytcheva ◽  
Velizar Gochev
Keyword(s):  
Methylene Blue ◽  
Congo Red ◽  
Contact Time ◽  
Order Kinetic ◽  
Batch Experiments ◽  
Streptomyces Fradiae ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Kinetic And Thermodynamic Studies ◽  
Pretreated Biomass

Pretreated waste Streptomyces fradiae biomass was utilized as an eco-friendly sorbent for Congo Red (CR) and Methylene Blue (MB) removal from aqueous solutions. The biosorbent was characterized by Fourier transform infrared spectroscopy. Batch experiments were conducted to study the effect of pH, biosorbent dosage, initial concentration of adsorbates, contact time and temperature on the biosorption of the two dyes. The equilibrium adsorption data were analysed using Freundlich and Langmuir models. Both models fitted well the experimental data. The maximum biosorption capacity of the pretreated Streptomyces fradiae biomass was 46.64 mg g-1 for CR and 59.63 mg g-1 for MB, at a pH 6.0, with the contact time of 120 min, the biosorbent dosage of 2 g dm-3 and the temperature of 298 K. Lagergren and Ho kinetic models were used to analyse the kinetic data obtained from different batch experiments. The biosorption of both dyes followed better the pseudo-second order kinetic model. The calculated values for ?G, ?S, and ?H indicated that the biosorption of CR and MB onto the waste pretreated biomass was feasible, spontaneous, and exothermic in the selected temperature range and conditions.

scholarly journals DEVELOPMENT AND VALIDATION OF A SPECTROPHOTOMETRIC METHOD TO EVALUATE BIOSAFETY CAPACITY OF BARU (Dipteryx alata) PEELS

2018 ◽  
Vol 15 (30) ◽  
pp. 221-240
Author(s):  
E. C. CESARINO ◽  
D. S. MULHOLLAND ◽  
W. FRANCISCO
Keyword(s):  
Contact Time ◽  
Limit Of Detection ◽  
Copper Ions ◽  
Maximum Adsorption Capacity ◽  
Limit Of Quantification ◽  
Experimental Conditions ◽  
Inorganic Matter ◽  
Pseudo Second Order ◽  
Development And Validation ◽  
Dipteryx Alata

This study developed a new analytical method using Molecular Absorption Spectroscopy (MAS) to track the ion cover in adsorption solution per peel (mesocarp) of Baru (Dipteryx alata). The adsorption study was conducted at different pH and contact time (kinetic), encountering 4.0 as the best pH for adsorption experimental conditions. The variation of contact time showed a pseudo-second-order adsorption kinetic behavior. The interpretation of the isotherms allowed to approach the Langmuir model with R² of 0.918 and to determine the maximum adsorption capacity (qmáx) as 11.481 mg.g⁻¹. The characterization of biomass by MAS in the Infrared (FT-IR) identified the possible functional groups belonging to protein, fatty acids and lipids, while thermal analysis (TG-DSC) showed a greater removal of inorganic matter by the biomass washed with water. The method underwent analytical validation, being classified as specific, sensitive, linear, robust, precise and accurate, with LD (limit of detection) and LQ (limit of quantification) equal to 3.873 and 12.912 mg.L⁻¹, respectively. The results obtained demonstrated the potential use of mesocarp Baru as a natural adsorbent for copper ions in solution, opening power for future expansion and improvement of the method.

scholarly journals The Novel Use of Saraca thaipingensis Leaf Powder as Potential Biosorbent Material for the Removal of Chromium(VI)

2015 ◽  
Vol 3 (3) ◽  
pp. 35-39
Author(s):  
Sannasi Palsan ◽  
Chai Swee Fern ◽  
Stephanie Bernardine ◽  
Lim Fan Shiang
Keyword(s):  
Heavy Metals ◽  
Particle Size ◽  
Contact Time ◽  
Low Cost ◽  
Peninsular Malaysia ◽  
The Novel ◽  
Batch Experiments ◽  
Chromium Vi ◽  
Removal Of Heavy Metals ◽  
Leaf Powder

Saraca thaipingensis or ‘Gapis’ tree, classified under the Fabaceae family is a native of Taiping; copious over Peninsular Malaysia and Southeast Asia. The withered and fallen dead leaves were collected from INTI International University’s garden walkway. To date, literature has yet to capture the use of S. thaipingensis tree parts or refuse as potential biosorbent material for the removal of heavy metals thus verifying the novelty of this study. Batch experiments were carried out with the leaf powder to study the effects of dosage, particle size and contact time towards Cr(VI) removal (%) at 1-100 mg/L. Results showed that Cr(VI) removal increased from 52.22% to 99.31% (p < 0.05) with increase in biosorbent dosage (0.005, 0.010, 0.015, 0.020, 0.025 and 0.050 g). The different particle size ranges tested were: 107-125, 126-150, 151-250, 251-500, and 501- 1000 ?m. Highest Cr(VI) removal of 99.53% was obtained with the 151-250 ?m particle size; further size decrease did not yield more removal (p > 0.05). The optimal Cr(VI) removal was recorded after 45 min (99.62%) and 90 min (99.76%) contact time (p > 0.05). Further characterization and optimization studies are being carried out to develop a novel, sustainable, low cost yet effective leaf powder based biosorbent material.

scholarly journals Adsorption of Deoxynivalenol (DON) from Corn Steep Liquor (CSL) by the Microsphere Adsorbent SA/CMC Loaded with Calcium

Toxins ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 208
Author(s):  
Ahmed Shalapy ◽  
Shuangqing Zhao ◽  
Chenxi Zhang ◽  
Yifei Li ◽  
Hairong Geng ◽  
...  
Keyword(s):  
Animal Feed ◽  
Physical Adsorption ◽  
Corn Steep Liquor ◽  
Reaction Times ◽  
Deionized Water ◽  
Infrared Spectrometry ◽  
Batch Experiments ◽  
Experimental Conditions ◽  
Carboxymethyl Cellulose Sodium ◽  
Steep Liquor

The occurrence of deoxynivalenol (DON) in animal feed is a serious issue for the livestock industry. Approaches using mycotoxin adsorbents are key to decreasing mycotoxin carryover from contaminated feed to animals. In this paper, a novel functional microsphere adsorbent comprising an alginate/carboxymethyl cellulose sodium composite loaded with calcium (SA/CMC-Ca) was prepared by an emulsification process to adsorb DON from polluted corn steep liquor (CSL) containing DON at a concentration of 3.60 μg/mL. Batch experiments were conducted under different experimental conditions: CSL volumes, reaction times, desorption times, and microsphere recyclability. Results showed that 5 g of microspheres reacted with 5 mL of DON-polluted CSL for 5 min, the microspheres can be recycled 155 times, and the maximum DON adsorption for the microspheres was 2.34 μg/mL. During recycling, microspheres were regenerated by deionized water every time; after the microspheres were cleaned, DON in the deionized water was degraded by sodium hydroxide (NaOH) at 70 °C for 1 h at pH 12. The mechanism for physical adsorption and hydrogen bonding was analyzed by scanning electron microscopy (SEM) and Fourier transform infrared spectrometry (FTIR). To the best of our knowledge, this is the first report showing that the microsphere adsorbent SA/CMC-Ca adsorbs DON. Therefore, we suggest that using microsphere absorbents would be a possible way to address DON-contaminated CSL issues in animal feed.

Phosphorus and Nitrogen Removal from Sewage by Modified Honeycomb Cinder

2013 ◽  
Vol 726-731 ◽  
pp. 2931-2935
Author(s):  
Qi Bin Liang ◽  
Yun Gen Liu ◽  
Kun Tian
Keyword(s):  
Nitrogen Removal ◽  
Phosphorus Removal ◽  
Contact Time ◽  
Low Cost ◽  
Ammonia Nitrogen ◽  
Domestic Sewage ◽  
Operating Conditions ◽  
Optimal Conditions ◽  
Batch Experiments ◽  
Adsorption Capacities

The study aimed at phosphorus and nitrogen removal by honeycomb cinder modified with Zinc chloride (ZnCl2). By bench-scale batch experiments, honeycomb cinders with different modification time and ZnCl2 dosage were modified and its adsorption capacities were evaluated by methylence blue as the adsorbate. Under the optimal modification conditions, large amount modified honeycomb cinders were prepared to remove the phosphorus and nitrogen from domestic sewage, which different operating conditions of honeycomb cinders dosage, and contact time were considered. The results show that removal efficiencies of total phosphate (TP), orthophosphate (PO43-P), total nitrogen (TN) and ammonia nitrogen (NH4+-N) could reach 89.9%, 96.7%, 18.9% and 23.3% under the optimal conditions, respectively. Modified honeycomb cinders might be an effective and low cost adsorbent for phosphorus removal.

Copper Biosorption and Bioprecipitation by Eichhornia spp. and Sulphate Reducing Bacteria

2009 ◽  
Vol 71-73 ◽  
pp. 561-564
Author(s):  
Shailesh R. Dave ◽  
M.S. Damani ◽  
D.R. Tipre
Keyword(s):  
Contact Time ◽  
Copper Removal ◽  
Point Of Zero Charge ◽  
Experimental Conditions ◽  
Element Analysis ◽  
Freundlich Isotherms ◽  
Biomass Influence ◽  
Reducing Bacteria ◽  
Influence Of Ph ◽  
Copper Sorption

Eichhornia spp. biomass collected from Chandola lake, Ahmedabad, Gujarat, India. Point of zero charge of the biomass was pH 7.3. Flask study showed pH 5 and 2 to 3 h contact time as optimum conditions for copper sorption. In 24 h of contact time, as high as 85% of copper was removed from 100 ppm copper containing solution. In first 2 h of the contact time the removal reached to 67.25%. Copper loading capacity of the biomass ranged between 2.85 to 1.0 g per 100 g of biomass. Influence of pH, temperature, nickel and zinc was studied by 24 factorial experiments. Under the experimental conditions pH and interactions between pH-nickel, temperature-pH and temperature-pH-nickel-zinc were found to be significant with 60 to 74.7% copper removal. As high as 95% of sorbed copper was desorbed with 0.1 N HNO3. Langmuir and Freundlich isotherms were also studied. Reactor study showed 90% overall copper removal from 25 L of copper containing waste and sulfatereducing bacteria played a significant role. Treatment of actual waste also showed 61% of copper removal. SEMquant element analysis showed presence of 12.39% w/w of copper in the biomass exposed to the waste, where as only 0.0018% of copper was detected in unexposed biomas

scholarly journals Optimization, equilibrium and kinetic studies of Zn2+ and Ni2+ adsorption from aqueous solutions using composite adsorbent

2018 ◽  
Vol 67 (3) ◽  
pp. 279-290 ◽  
Author(s):  
Haider M. Zwain ◽  
Mohammadtaghi Vakili ◽  
Irvan Dahlan
Keyword(s):  
Contact Time ◽  
Coal Fly Ash ◽  
Sol Gel ◽  
Freundlich Isotherm ◽  
Kinetic Studies ◽  
Isotherm Models ◽  
Experimental Conditions ◽  
Palm Oil Fuel Ash ◽  
Composite Adsorbent ◽  
Oil Fuel

Abstract A novel RHA/PFA/CFA composite adsorbent was synthesized from rice husk ash (RHA), palm oil fuel ash (PFA), and coal fly ash (CFA) by modified sol-gel method. Effect of different parameters such as adsorbent dosage, contact time, and pH were studied using batch experiment to optimize the maximum zinc (Zn2+) and nickel (Ni2) adsorption conditions. Results showed that the maximum adsorption condition occurred at adsorbent amount of 10 g/L, contact time of 60 min, and pH 7. At this condition, the removal efficiencies were 81% and 61% for Zn2+ and Ni2+, in which the adsorption capacities (qmax) were 21.74 mg/g and 17.85 mg/g, respectively. Adsorption behavior of RHA/PFA/CFA composite adsorbent was studied through the various isotherm models at different adsorbent amounts. The results indicated that the Freundlich isotherm model gave an excellent agreement with the experimental conditions. Based on the results obtained from the kinetic studies, pseudo-second-order was suitable for the adsorption of Ni2+ and Zn2+, compared to the pseudo-first-order model. The results presented in this study showed that RHA/PFA/CFA composite adsorbent successfully adsorbed Zn2+ and Ni2.

THM formation during chlorination of treated municipal wastewater

2002 ◽  
Vol 2 (3) ◽  
pp. 235-242 ◽  
Author(s):  
E. Koukouraki ◽  
E. Diamadopoulos
Keyword(s):  
Organic Carbon ◽  
Contact Time ◽  
Municipal Wastewater ◽  
Secondary Effluent ◽  
Batch Experiments ◽  
Limited Effect ◽  
Formation Potential ◽  
Coagulation Tests ◽  
Treated Municipal Wastewater

Chlorination batch experiments were conducted in order to estimate the concentration of THM and their formation potential in nitrified and partially nitrified secondary effluent. The role of contact time (up to 2 hours), chlorine dose (3 levels), pH and temperature on the formation of THM was evaluated. THM formation, as measured by individual concentration as well as formation potential, was high for the nitrified secondary effluent, while for the partially nitrified effluent the respective concentrations were low, due to the reaction of chlorine with ammonia to form chloramines. In general, THM concentrations progressively increased as contact time, pH and chlorine dose increased. Increase in temperature (from 15-25°C) showed a rather limited effect. In addition, coagulation tests were applied prior to chlorination of the nitrified effluent for removing organic carbon and thereby controlling the formation of THM. Alum was used as the coagulant in doses varying from 0.1 mM to 2.5 mM. As the coagulant dose increased, the removal of both DOC and absorbance at 254 nm increased, while THM formation decreased. The reduction in THM formation was more pronounced for coagulant doses higher than 1.5 mM.

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