Amination of biochar surface from watermelon peel for toxic chromium removal enhancement

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The difference between physical activations (by sonications) and chemical activations (by ammonia) on sawdust biochar has been investigated in this study by comparing the removal of Cu(II) ions from an aqueous medium by adsorption on sawdust biochar (SD), sonicated sawdust biochar (SSD), and ammonia-modified sawdust biochar (SDA) with stirring at room temperature, pH value of 5.5–6.0, and 200 rpm. The biochar was prepared by the dehydrations of wood sawdust by reflux with sulfuric acid, and the biochar formed has been activated physically by sonications and chemically by ammonia solutions and then characterized by the Fourier transform infrared (FTIR); Brunauer, Emmett, and Teller (BET); scanning electron microscope (SEM); thermal gravimetric analysis (TGA); and energy-dispersive spectroscopy (EDX) analyses. The removal of Cu(II) ions involves 100 mL of sample volume and initial Cu(II) ion concentrations (conc) 50, 75, 100, 125, 150, 175, and 200 mg L−1 and the biochar doses of 100, 150, 200, 250, and 300 mg. The maximum removal percentage of Cu(II) ions was 95.56, 96.67, and 98.33% for SD, SSD, and SDA biochars, respectively, for 50 mg L−1 Cu(II) ion initial conc and 1.0 g L−1 adsorbent dose. The correlation coefficient (R2) was used to confirm the data obtained from the isotherm models. The Langmuir isotherm model was best fitted to the experimental data of SD, SSD, and SDA. The maximum adsorption capacities (Qm) of SD, SSD, and SDA are 91.74, 112.36, and 133.33 mg g−1, respectively. The degree of fitting using the non-linear isotherm models was in the sequence of Langmuir (LNR) (ideal fit) > Freundlich (FRH) > Temkin (SD and SSD) and FRH (ideal fit) > LNR > Temkin (SDA). LNR and FRH ideally described the biosorption of Cu(II) ions to SD and SSD and SDA owing to the low values of χ2 and R2 obtained using the non-linear isotherm models. The adsorption rate was well-ordered by the pseudo-second-order (PSO) rate models. Finally, chemically modified biochar with ammonia solutions (SDA) enhances the Cu(II) ions’ adsorption efficiency more than physical activations by sonications (SSD). Response surface methodology (RSM) optimization analysis was studied for the removal of Cu(II) ions using SD, SSD, and SDA biochars.

Section: The Morphological Properties Of the Sawdust Biochars Surfacessupporting

confidence: 85%

“…The bands at 1193, 1179, and 1172 cm −1 in SD, SSD, and SDA biochars indicate the presence of oxygenated carbon chains C-O-C. The bands at 1030, 1032, and 1029 cm −1 in SD, SSD, and SDA were related to the C-O-H FGs [58][59][60].…”

Section: Estimating Biochar Surface Fgs By Ftirmentioning

confidence: 92%

Copper(II) ion removal by chemically and physically modified sawdust biochar

Eleryan

Aigbe

Ukhurebor

et al. 2022

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“…Bands in biochars between 1470 and 900 cm −1 represent C-O functional groups and show no significant changes as a result of the different treatments applied to the SD biochar. The bands at 1027, 1029, and 1033 cm −1 in SDO, PSD, and SSD, respectively, are related to the C-O-H functional group [36,37,62].…”

Section: Estimation Of Biochar Surface Functional Groups By Ftirmentioning

confidence: 98%

Adsorption of methylene blue (MB) dye on ozone, purified and sonicated sawdust biochars

Eldeeb

Aigbe

Ukhurebor

et al. 2022

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The synthesized biochars derived from sawdust (SD) SD ozone (SDO) biochar, purified SD (PSD) biochar, and sonicated SD (SSD) biochar, which was employed in the confiscation of methylene blue (MB) dye ion, were characterized employing “Brunauer–Emmett–Teller (BET), scanning electron microscope (SEM), Fourier Transform Infrared (FTIR), and Thermal gravimetrical analysis (TGA).” The impact of various factors, such as pH, biochar dosage, and initial concentration, on MB dye sequestration, was tested in this study. It was found that the biosorption of MB dye to the various biochars was dependent on the solution pH, with optimum confiscation of MB observed at pH 12 for all biochars. Pseudo-second-order (PSO), Freundlich (FRH)- (SDO and SSD biochars), and Langmuir (LNR)- (PSD biochar) models were used to best describe the biosorption process of MB dye to various biochars. Based on the LNR model fitting to the experimental data, the optimum sorption capacities obtained using SDO, SSD, and PSD biochars were 200, 526, and 769 mg/g, respectively. Electrostatic interaction and hydrogen bonding played an important role in the interaction mechanism between the various biochars and MB dye. Hence, these studied SDO, PSD, and SSD biochars prepared from cheap, easily accessible, biodegradable, and non-hazardous agro-waste materials can be effectively used for the removal, treatment, and management of MB dye as well as other industrial effluents before their disposal into the environment.

“…Scientists have proposed different methods such as membrane separation, chemical precipitation, adsorption, biological treatment, redox, and ion exchange to remove heavy metal ions from wastewaters [16][17][18][19][20][21][22][23]. Among these techniques, the adsorption technique has been the preferred method since it eliminates some disadvantages such as high equipment cost, toxic sludge, and other waste production seen in other methods [24][25][26][27][28][29]. Zeolite, activated carbon, chitosan, graphene, and agroforestry wastes are widely used in the treatment of Cr 6+ ions, a toxic heavy metal, from wastewater [30][31][32][33][34][35][36][37][38].…”

Section: Introductionmentioning

confidence: 99%

Biochar-SO prepared from pea peels by dehydration with sulfuric acid improves the adsorption of Cr6+ from water

El‐Nemr

Yılmaz

Ragab

et al. 2022

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A new biochar was produced from pea peel residues by the dehydration process. The effect of the obtained new biochar on the ability to remove Cr6+ ions from the aqueous solution was investigated. Biochar-SO was obtained from pea peel by dehydration of biochar with 50% sulfuric acid. The obtained biochars were characterized by Fourier transform infrared (FT-IR); Brunauer, Emmett and Teller (BET); Barrett-Joyner-Halenda (BJH); thermogravimetric analysis (TGA); differential scanning calorimetry (DSC); scanning electron microscope (SEM); and energy-dispersive X-ray (EDAX) analyses. The optimum pH value for Cr6+ ion removal was determined as 1.48. The maximum removal percentage of Cr6+ ions was 90.74% for Biochar-SO of 100 mg·L−1 Cr6+ ions initial concentration and 1.0 g L−1 adsorbent dosage. The maximum adsorption capacity (Qm) of biochar-SO was 158.73 mg·g−1. The data obtained were analyzed with Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich (D-R) isotherm models. In addition, the data obtained from these isotherm models were tested using different error functions (hybrid error function (HYBRID), average percent errors (APE), the sum of the absolute errors (EABS), chi-square error (X2), and Marquardt’s percent standard deviation (MPSD and the root mean square errors (RMS)) equations. It was the Freundlich isotherm model that best fits the experimental data of biochar-SO. Kinetic data were evaluated by pseudo–first-order (PFO), pseudo–second-order (PSO), Elovich, and intraparticle diffusion models. The adsorption rate was primarily controlled by the PSO rate model with a good correlation (R2 = 1). The adsorption mechanism of biochar-SO to remove Cr6+ ions can be based on electrostatic interaction and ion exchange with exchangeable cations in biochar such as aluminum, silicon, and calcium ions for chromium. The results indicate that biochar-SO is a promising adsorbent for the adsorption of Cr6+ ions that can be employed repeatedly without substantial loss of adsorption effectiveness.