3D Porous Structure-Inspired Lignocellulosic Biosorbent of Medulla tetrapanacis for Efficient Adsorption of Cationic Dyes

Preparation of a Novel Lignocellulose-Based Aerogel by Partially Dissolving Medulla Tetrapanacis via Ionic Liquid

A novel lignocellulosic aerogel, MT-LCA, was successfully prepared from MT by undergoing partial dissolution in an ionic liquid, coagulation in water, freezing in liquid nitrogen, and subsequent freeze-drying. The MT-LCA preserves its original honeycomb-like porous structure, and the newly formed micropores contribute to increased porosity and specific surface area. FT-IR analysis reveals that MT, after dissolution and coagulation, experiences no chemical reactions. However, a change in the crystalline structure of cellulose is observed, transitioning from cellulose I to cellulose II. Both MT and MT-LCA demonstrate a quasi-second-order kinetic process during methylene blue adsorption, indicative of chemical adsorption. The Langmuir model proves to be more appropriate for characterizing the methylene blue adsorption process. Both adsorbents exhibit monolayer adsorption, and their effective adsorption sites are uniformly distributed. The higher porosity, nanoscale micropores, and larger pore size in MT-LCA enhance its capillary force, providing efficient directional transport performance. Consequently, the prepared MT-LCA displays exceptional compressive performance and efficient directional transport capabilities, making it well-suited for applications requiring high compressive performance and selective directional transport.

Co-pyrolysis of orange peel and eggshell for oxygenated rich composite: Process optimization with response surface methodology

Co-pyrolysis of orange peel and chicken eggshell was performed for the synthesis of the composite, a co-pyrolysis technique used to promote natural fabrication and to allow the raw material elemental combination effect and the preparatory conditions such as pyrolysis temperature, residence time, and eggshell/orange peel mixing ratio, to be optimized with the response surface methodology through Box-Behnken Design(BBD). BBD involved a randomized series of 17 experimental runs, and the best optimal conditions were found with a pyrolysis temperature of 300 °C, a residence time of 1 h, and 0.5 as the mixing ratio. These conditions gave a maximum adsorption capacity of 167 mg/g for removal of the modal pollutant methylene blue. FTIR spectra of the composite showed new functional peaks of oxygenated groups, at two different bands. XRD confirmed an amorphous surface with inorganic component peaks, while SEM-EDS revealed rich defects sites along with an enhanced percentage of oxygen elements on the surface; the surface area was enhanced from 1 m2 with unmodified peel to 64 m2 with composite. The adsorption behavior of the composite was studied for dye removal and the adsorption behavior was well explained by the Langmuir isotherm model.

Enhanced adsorption of Congo red from urea/calcium chloride co-modified biochar: Performance, mechanisms and toxicity assessment

Adsorbents with excellent physicochemical properties and green synthetic routes are desired for efficient removal of Congo red (CR) wastewater. Hence, a novel approach was proposed within this work. Biochar NCBC obtained from Medulla Tetrapanacis was synthesized through co-modification with urea/calcium chloride. NCBC exhibited an enormous surface area (750.09 m2/g) and a micro-mesoporous composite structure. Higher nitrogen content was detected on the surface of NCBC (8.17%) compared to that of urea directly modified biochar (4.63%). Nitrogen observed on the surface of NCBC was presented as graphitic N, pyrrolic N, amine N as well as pyridinic N. Kinetic and isothermal investigations revealed the active sites on NCBC to be homogeneous and bind to CR mainly by chemisorption. Calculated maximum sorption of CR on NCBC was 2512.82 mg/g basing on Langmuir model. Moreover, the practicality of NCBC was further proved by the cultivation of Nelumbo nucifera Gaertn. and Penicillium.

Efficient removal of Congo red and methylene blue using biochar from Medulla Tetrapanacis modified by potassium carbonate

Biochar (BC) prepared from Medulla Tetrapanacis was recognized as having potential in environmental remediation because of its porous texture, abundant chemical surface groups and mineral composition. In this study, a novel modified biochar (KBC) derived from Medulla Tetrapanacis achieved efficient adsorption of Congo red (CR) and methylene blue (MB). Characterization results suggested that the modification had little effect on the group distribution of KBC, but a dramatic expansion of specific surface area was observed on KBC (1180.45 m2/g) compared to BC (198.51 m2/g). KBC exhibited a maximum sorption of 584.17 mg/g for CR and 318.01 mg/g for MB. Kinetic and isotherm studies revealed sorption of CR and MB by KBC was chemosorption, which occurred on the monolayer surface. The comprehensive analysis also provided the basis for the application of KBC to practical production. These outcomes suggested that KBC may become a new option for the effluent treatment.

Synthesizing nanoparticles of zinc and copper ferrites and examining their potential to remove various organic dyes through comparative studies of kinetics, isotherms, and thermodynamics

Nanoparticles of zinc ferrite (ZnFe₂O₄) and copper ferrite (CuFe₂O₄) were synthesized, and characterized, and these materials were applied for removal of organic dyes of alizarin yellow R (AYR), thiazole yellow G (TYG), Congo red (CR), and methyl orange (MO) from industrial wastewater through adsorption technique. Synthesis of ZnFe₂O₄ and CuFe₂O₄ was achieved through chemical co-precipitation method. These nanomaterials were characterized for physicochemical properties using XRD, FTIR, BET, VSM, DLS, Zeta-potential, and FESEM-EDX analytical instruments. BET surface areas of ZnFe₂O₄ and CuFe₂O₄ were 85.88 m²/g and 41.81 m²/g, respectively. Adsorption-influencing parameters including effect of solution pH, adsorbent quantity, initial concentration of dye pollutant, and contact time were examined. Acidic medium of the solution favored higher percentage of removal of dyes in wastewater. Out of different isotherms, Langmuir equilibrium isotherm showed the best fit with experimental data, indicating monolayer adsorption in the treatment process. The maximum monolayer adsorption capacities were found as 54.58, 37.01, 29.81, and 26.83 mg/g with ZnFe₂O₄, and 46.38, 30.06, 21.94, and 20.83 mg/g with CuFe₂O₄ for AYR, TYG, CR, and MO dyes, respectively. From kinetics analysis of the results, it was inferred that pseudo-second-order kinetics were fitting well with better values of coefficient of determination (R²). The removal of four organic dyes from wastewater through adsorption technique using nanoparticles of ZnFe₂O₄ and CuFe₂O₄ was observed to be spontaneous and exothermic. From this experimental investigation, it has been inferred that magnetically separable ZnFe₂O₄ and CuFe₂O₄ could be a viable option in removal of organic dyes from industrial wastewater.

Efficient and Selective Removal of Organic Cationic Dyes by Peel of Brassica juncea Coss. var. gemmifera Lee et Lin-Based Biochar

The design and preparation of cheaper, greener and more efficient adsorbents is essential for the removal of pollutants by adsorption. In this study, biochar was prepared from peel of Brassica juncea var. gemmifera Lee et Lin (PoBJ) using a facile, low-temperature and vacuum pyrolysis, and the adsorption mechanism toward organic dyes in aqueous solution was elucidated. The adsorbent was characterized by XPS, FT-IR and SEM, and zeta potential techniques. The adsorption ability of PoBJ biochar for cationic dyes (methylene blue, brilliant green, calcein-safranine, azure I, rhodamine B), anionic dyes (alizarin yellow R), and neutral dyes (neutral red) revealed that the biochar exhibited adsorption selectivity toward cationic dyes. The effects of different factors on the adsorption performance of PoBJ biochar, as well as the adsorption kinetics and thermodynamics, were further investigated by using methylene blue as the model adsorbate. These factors included temperature, pH, contact time and dye concentration. The experimental results showed that BJ280 and BJ160 (prepared at 280 °C and 160 °C, respectively) possessed relatively higher adsorption capacity of 192.8 and 167.40 mg g^-1 for methylene blue (MB), respectively, demonstrating the possibility of utilization of PoBJ biochar as a superior bio-adsorbent. The experimental data of BJ160 toward MB were correlated with various kinetic and isothermal models. The results indicated that the adsorption process was consistent with the Langmuir isotherm model and nonlinear pseudo-second-order kinetic model. Thermodynamic parameters indicated that the adsorption of MB onto BJ160 was exothermic. Thus, the low-temperature prepared PoBJ biochar was an environmentally friendly, economic and efficient cationic dye adsorbent.