Abatement of Cr (VI) from wastewater using a new adsorbent, cantaloupe peel: Taguchi L16 orthogonal array optimization

Bahman Ramavandi,Ghorban Asgari,Javad Faradmal,Soleyman Sahebi,Babak Roshani 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.12

Taguchi orthogonal design was applied for multivariate optimization of Cr (VI) abatement by canta-loupe peel powder (CPP), as a novel adsorbent, from industrial wastewater in a batch mode. Effective factors in theadsorption process, such as temperature, CPP dose, Cr (VI) concentration, wastewater pH, and contact time, were con-sidered using an L16 orthogonal array design. The best conditions for adsorbing of Cr (VI) were determined by the Taguchimethod and desirability approach as pH of 2, chromium concentration of 100 mg/L, contact time of 5 min, CPP dosageof 0.5 g/L, and wastewater temperature of 25 oC. Analysis of variance results indicated that the pH was the most im-portant variable influencing the chromium removal percentage, and its contribution value was obtained 45.01%. TheLangmuir model proved best fit for the experimental data and maximum adsorption capacity of Cr (VI) onto CPP wasobtained 166.25 mg/g. The final part of the study includes an examination of the CPP through an analysis of the removalof chromium from real industrial wastewater. It can be concluded that the CPP presents a promising and efficient al-ternative for eliminating of Cr (VI) from industrial wastewaters.

Removal of chemical oxygen demand from textile wastewater using a natural coagulant

Bahman Ramavandi,Sima Farjadfard 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.1

A biomaterial was successfully synthesized from Plantago ovata by using an FeCl3-induced crude extract (FCE). The potential of FCE to act as a natural coagulant was tested for the pretreatment of real textile wastewater. Tests were performed to evaluate the effects of FCE quantity, salt concentration, and wastewater pH on chemical oxygen demand (COD) reduction during a coagulation/flocculation process. Experimental results indicated that the wastewater could be effectively treated by using a coagulation/flocculation process, where the BOD5/COD ratio of the effluent was improved to 0.48. A low coagulant dose, 1.5mg/L, achieved a high COD removal percentage, 89%, at operational conditions of neutral pH and room temperature. The experimental data revealed that the maximum COD removal occurred at water pH<8. Increasing the salt promoted the COD removal. The settling and filterability characteristics of the sludge were also studied. Scanning electron microscopy and energy dispersive spectroscopy studies were conducted to determine the sludge structure and composition, respectively. Overall, FCE as an eco-friendly biomaterial was revealed to be a very efficient coagulant and a promising option for the removal of COD from wastewaters.

Physico-chemical study of dew melon peel biochar for chromium attenuation from simulated and actual wastewaters

Bahman Ramavandi,Mehdi Ahmadi,Esmaeil Kouhgardi 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.9

This work introduces a biochar as novel adsorbent prepared from the dew melon peel by pyrolysis method, and demonstrates its potential for eliminating Cr(VI) from simulated and actual wastewaters. The dew melon peel biochar (DPB) was characterized by several techniques and methodologies such as, BET, SEM, FTIR, Boehm titration, ultimate analysis, and pHzpc. DPB is a microporous material with the BET specific surface area of 196m2/g. The effects of different parameters including pH, amount of adsorbent, Cr(VI) concentration, and mixing time on the removal of Cr(VI) from wastewater were studied. Maximum adsorption (98.6%) was observed at pH 6 and 100mg/L metal concentration. The equilibrium adsorption was analyzed by Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich isotherms. Kinetic data were evaluated by pseudo-first order, pseudo-second order, intraparticle diffusion, film diffusion (Boyd), Elovich, and Avrami models. The kinetic data were best fitted to the pseudo-second order model. The Langmuir isotherm model gives the better correlation to predict the adsorption equilibrium, with a maximum adsorption capacity of 198.7mg/g. The thermodynamic parameters showed that the adsorption of Cr(VI) was endothermic and spontaneous. Competition between the co-existing ions of Cl−, NO3 −, SO4 2−, PO4 3−, and HCO3 − on the adsorption process was studied. The efficacy of DPB was successfully examined by analyzing the removal of Cr(VI) from two industrial wastewaters. The results indicate that DPB is promising as an effective and economical adsorbent for Cr(VI) ions removal and could be repeatedly used with no significant loss of adsorption efficiency.

Treatment of chromium-laden aqueous solution using CaCl2-modified Sargassum oligocystum biomass: Characteristics, equilibrium, kinetic, and thermodynamic studies

Rauf Foroutan,Reza Mohammadi,Bahman Ramavandi 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.1

Biosorption properties of a CaCl2-modified Sargassum oligocystum algae biomass for removal of Cr(VI) from aqueous solutions were investigated. Experimental parameters affecting the biosorption process such as pH, contact time, biosorbent dosage, and temperature were studied. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), mapping test, energy-dispersive X-ray spectroscopy (EDX), and specific surface area were used to assess the physico-chemical properties the biosorbent. The surface area of biosorbent was found to be 35.64m2/g. FTIR test revealed that the active groups of -OH, -NH2, -C-H, C-O, -C-N, and S=O were present on the surface of CaCl2-modified S. oligocystum biomass. The kinetic behavior of the chromium biosorption by modified S. oligocystum biomass followed well pseudo-second order kinetic (R2>0.999). The biosorption equilibrium occurred at 100th min of contact time. The Langmuir, Freundlich, and Dubinin-Radushkevich models were applied to describe the biosorption isotherm of Cr(VI) onto modified S. oligocystum biomass. According to the RL and n parameters of the studied isotherms, the Cr(VI) biosorption process was physical and desirable. The chromium biosorption capacity of modified S. oligocystum biomass was found to be 34.46mg/g. The calculated thermodynamic parameters (ΔGo, ΔHo, and ΔSo) indicated that the biosorption of Cr(VI) onto modified S. oligocystum biomass algae was feasible, spontaneous, and exothermic under examined conditions.

Magnetic nanocomposite of filamentous algae activated carbon for efficient elimination of cephalexin from aqueous media

Shirin Afshin,Yousef Rashtbari,Bahman Ramavandi,Mehdi Fazlzadeh,Mehdi Vosoughi,Seyad Ahmad Mokhtari,Mohammad Shirmardi,Rabia Rehman 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.1

Discharge of antibiotics into the environment can cause problems like increase of the microorganisms' resistance, disturbing the ecological balance and increasing the allergy in humans. In this research, an activated carbon was produced from filamentous algae and then magnetized with Fe3O4. The adsorbent size was nano-scale and its characteristics were studied using XRD, FT-IR, FE-SEM, BET and VSM techniques. The response surface method (RSM) was employed to optimize the operating parameters and determine the best conditions for cephalexin removal by novel composite of AC-Fe3O4. The various parameters in the process, such as reaction time, initial pH, adsorbent dose, initial concentration of cephalexin and effect of cations and anions that could interfere in the adsorption of cephalexin were evaluated in three levels. The proposed quadratic model was found to be best suggested model for the adsorption process (R2=0.99094 and R2 adj=0.9991). According to results, the parameters such as cephalexin concentration, the adsorbent dose, the reaction time and the pH value were found to be 28.16mg/L, 2 g/L, 30.04 and 3.02, respectively. Experimental results showed that the adsorption of cephalexin followed Langmuir isotherm (R2=0.9803). Also, the results showed cephalexin adsorption on the composite fitted pseudo-second-order kinetics. The study showed that the AC-Fe3O4 adsorbent has high efficacy for eliminating cephalexin from aqueous solution.

Removal characteristics of chromium by activated carbon/CoFe2O4 magnetic composite and Phoenix dactylifera stone carbon

Rauf Foroutan,Reza Mohammadi,Bahman Ramavandi,Maryam Bastanian 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.11

Activated carbon (AC) was synthesized from Phoenix dactylifera stones and then modified by CoFe2O4 magnetic nanocomposite for use as a Cr(VI) adsorbent. Both AC/CoFe2O4 composite and AC were fully characterized by FTIR, SEM, XRD, TEM, TGA, and VSM techniques. Based on the surface analyses, the addition of CoFe2O4 nanoparticles had a significant effect on the thermal stability and crystalline structure of AC. Factors affecting chromium removal efficiency like pH, dosage, contact time, temperature, and initial Cr(VI) concentration were investigated. The best pH was found 2 and 3 for Cr adsorption by AC and AC/CoFe2O4 composite, respectively. The presence of ion sulfate had a greater effect on the chromium sorption efficiency than nitrate and chlorine ions. The results illustrated that both adsorbents can be used up to seven times to adsorb chromium. The adsorption process was examined by three isothermal models, and Freundlich was chosen as the best one. The experimental data were well fitted by pseudo-second-order kinetic model. The half-life (t1/2) of hexavalent chromium using AC and AC/CoFe2O4 magnetic composite was obtained as 5.18min and 1.52min, respectively. Cr(VI) adsorption by AC and AC/CoFe2O4 magnetic composite was spontaneous and exothermic. In general, our study showed that the composition of CoFe2O4 magnetic nanoparticles with AC can increase the adsorption capacity of AC from 36mg/L to 70mg/L.

Adsorptive performance of calcined Cardita bicolor for attenuating Hg(II) and As(III) from synthetic and real wastewaters

Abolfazl Teimouri,Hossein Esmaeili,Rauf Foroutan,Bahman Ramavandi 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.2

The first application of calcined Cardita bicolor oyster shell (CCBS) for Hg(II) and As(III) adsorption from synthetic and real wastewaters was tested. The main elements in CCBS structure were carbon, oxygen, magnesium, phosphor, and calcium. Effects of different parameters like initial pH, contact time, temperature, and CCBS dosage were assessed. The results showed that the maximum recovery of Hg(II) and As(III) adsorption was determined as C0=10mg/L, t=80 min, T=25 oC, CCBS dosage=5 g/L, and pH=6 (for mercury ion) and 7 (for arsenic ion). In these conditions, 95.72% Hg(II) and 96.88% As(III) were removed from aqueous solution. The correlation coefficient (R2) values for both adsorbates were obtained >0.98 and >0.96 for Langmuir and Freundlich isotherm models, respectively. Pseudo-second-order kinetic model was more capable to describe kinetic behavior of adsorption process of both metal ions in comparison with pseudo-first-order model. The half life (t1/2) value for Hg(II) and As(III) with initial concentration of 10mg/L was 4.032 and 4.957 min, respectively. Moreover, thermodynamic parameters of enthalpy (ΔHo), entropy (ΔSo), and Gibbs free energy (ΔGo) were investigated. Two real wastewaters obtained from a leather factory and a landfill leachate were successfully treated using CCBS. The results confirmed that adsorption process of metals ions was exothermic and spontaneous.

Date seed activated carbon decorated with CaO and Fe3O4 nanoparticles as a reusable sorbent for removal of formaldehyde

Hossein Khaleghi,Hossein Esmaeili,Neamatollah Jaafarzadeh,Bahman Ramavandi 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.1

Activated carbon (AC) was produced from date seeds by a calcination process at 700 oС for 2 h and then its surface was improved with CaO and magnetic nanoparticles. AC/CaO/Fe3O4 nanocomposite was then employed to remove formaldehyde ions from aqueous media. The structural characteristics of the materials were completely studied through FT-IR, XRD, SEM, EDX, Map, VSM, BET and TEM analyses. The results showed that the nanocomposite has a mesoporous structure (average pore diameter~13 nm) with great sorption capability. Also, the utmost removal efficiency of formaldehyde using AC, AC/Fe3O4, CaO/Fe3O4 and AC/Fe3O4/CaO nanocomposite was 94.73, 95.67, 95.14 and 98.22%, respectively, indicating that the removal efficiency increases by improving the surface properties of the AC. Moreover, the uptake of formaldehyde using AC/Fe3O4/CaO nanocomposite follows the Freundlich isotherm and pseudo-2nd-order kinetic models. Furthermore, the highest sorption capacity of AC, AC/Fe3O4, CaO/Fe3O4 and AC/ Fe3O4/CaO nanocomposite using the Langmuir model was obtained 19.86, 24.21, 21.28 and 24.01mg/g, respectively. The thermodynamic study showed that formaldehyde sorption using all four adsorbents is exothermic and spontaneous. The reusability of the adsorbents was also evaluated after ten reuse cycles and the outcomes indicated that these four adsorbents have significant reusability. Moreover, the impact of interfering ions (e.g., carbonate, sulfate, phosphate, nitrate and chloride) showed that all of these compounds, except nitrate, had little competition with formaldehyde ions for adsorption on the nanocomposite surface.

Ultrasonic-assisted synthesis of Populus alba activated carbon for water defluorination: Application for real wastewater

Ziaeddin Bonyadi,Ponnusamy Senthil Kumar,Rauf Foroutan,Raheleh Kafaei,Hossein Arfaeinia,Sima Farjadfard,Bahman Ramavandi 한국화학공학회 2019 Korean Journal of Chemical Engineering Vol.36 No.10

Efficient activated carbon was ultrasonically synthesized from the Populus alba tree, and fluoride ions were removed from samples of synthetic and real wastewaters. The effects of various parameters including pH (2-10), time (5-180 min), contaminant concentration (10-100mg/L), sorbent dose (1-7 g/L), and co-existing ions on the fluoride removal using Populus alba activated carbon (PAAC) were revealed. The physico-chemical characteristics of PAAC were determined using SEM, FTIR, BET, XRD, and EDX mapping. The specific surface area and pore volume of the mesoporous PAAC were obtained as 707.39m2/g and 0.40m3/g. The study found that the maximum removal efficiency of fluoride (93.37%) occurred under the fluoride concentration of 10mg/L, PAAC of 4 g/L, pH of 6, and contact time of 100 min. The isotherms and kinetics data could be suitably reflected by the Freundlich and the pseudosecond- order kinetic models, respectively. Langmuir maximum monolayer adsorption capacity of the ultrasonicassisted PAAC was measured as 77.12mg/g. Sorption of fluoride ions onto PAAC is feasible and an exothermic process. According to the field test, PAAC can significantly remove fluoride and other pollutants like BOD5, COD, Ni, Co, and Pb from glass and shipyard wastewater samples.