Rapid nitrogen-rich modification of Calotropis gigantea fiber for highly efficient removal of fluoroquinolone antibiotics

A review of the adsorption method for norfloxacin reduction from aqueous media

Norfloxacin (NRFX) is one of a class of antibiotics known as broad-spectrum fluoroquinolone antibiotic that is frequently used to treat infectious disorders in both animals and humans. NRFX is considered an emergent pharmaceutical contaminate. This review's objective is to evaluate empirical data on NRFX's removal from aqueous medium. The environmental danger of NRFX in the aquatic environment was validated by an initial ecotoxicological study. Graphene oxide/Metal Organic Framework (MOF) based composite, followed by Magnesium oxide/Chitosan/Graphene oxide composite gave the highest NRFX adsorption capacities (Qmax) of 1114.8 and 1000 mg/g, respectively. The main adsorption mechanisms for NRFX uptake include electrostatic interactions, H-bonds, π-π interactions, electron donor-acceptor interactions, hydrophobic interactions, and pore diffusion. The adsorptive uptake of NRFX were most suitably described by Langmuir isotherm and pseudo-second order implying adsorbate-to-adsorbent electron transfer on a monolayer surface. The thermodynamics of NRFX uptake is heavily dependent on the makeup of the adsorbent, and the selection of the eluent for desorption from the solid phase is equally important. There were detected knowledge gaps in column studies and adsorbent disposal method. There's great interest in scale-up and industrial applications of research results that will aid in management of water resources for sustainability.

Characterization and valuable use of Calotropis gigantea seedpods as a biosorbent of methylene blue

In this work, powdered Calotropis gigantea seedpods were characterized and used as biosorbents of methylene blue dye from aqueous solution. FT-IR spectroscopy demonstrated functional groups characteristics of cellulose. Steric exclusion chromatography donated an average molecular weight of 230 kg/mol of the biopolymer. The polymolecularity index value (1.95) proved the good homogeneity of the polysaccharide. Scanning electron microscopy features displayed a homogenous morphology and porous structure. X-ray diffraction patterns showed peaks characteristics of cellulose and non-cellulose compositions. Thermogravimetric analysis/differential thermal analysis displayed exothermal decompositions at 316.9 °C and 456 °C. The maximum biosorption capacity of methylene blue was 88.36 mg/g at pH = 6, time = 60 min, and T = 21 °C. The level was comparable to some other studied agricultural wastes. The adsorption mechanism followed pseudo-second-order and Freundlich models. As it is abundant, available, low-cost, and easily recovered from solution, C. gigantea seedpods could be used as an effective biomaterial for the removal of organic pollutants from contaminated waters. Novelty statement: An abundant, available, and low-cost Calotropis gigantea seedpod was used, for the first time, as an effective biomaterial for the biosorption of organic pollutants. The biosorption level was found to be comparable to some other agricultural wastes studied previously in the literature.

A batch study on the adsorption/desorption behavior of vancomycin on bentonite nanoparticles in aqueous solutions

In this study, adsorption/desorption of vancomycin (VAN) on bentonite nanoparticles was investigated in a batch system. Adsorption experiments were carried out as a function of several influential parameters such as adsorbent dosage, pH, contact time and ionic strength. Bentonite nanoparticles were characterized by field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, Brunauer-Emmett-Teller, and Fourier transform infrared (FTIR) analyses and the mesoporous structure was revealed. Langmuir, Freundlich, and Temkin isotherm models were applied for the examination of equilibrium data, and Langmuir was found to be the best fit. With the increase in pH and ionic strength, the adsorption capacity decreases, which suggests the adsorption process may be dominated by the cation exchange mechanism. Moreover, VAN desorption from bentonite nanoparticles in two initial VAN loadings was investigated under different concentrations of metallic cations of various valences (Na⁺, Ca²⁺, Al³⁺), and pHs 3-10. Desorption was strongly pH-dependent and the amount of VAN desorbed increased with increasing cations concentrations. The FTIR analysis before and after VAN desorption suggests that the formation of Al-VAN and Ca-VAN complexes on the solid surface and then their detachment from the solid surface may contribute to the higher VAN desorption by Al³⁺ and Ca²⁺.

Chemical Constituents and Uses of Calotropis Procera and Calotropis Gigantea – A Review (Part I – The Plants as Material and Energy Resources)

The traditional and current use of Calotropis procera and C. gigantea, two soft-wooded, xerophytic shrubs of the family Apocynaceae, are reviewed against the background of the plants' chemical constituents and their biological properties. The focus is on the usage of the plants for building materials, natural pesticides, animal feed and bioremediative purposes.

Use of chemically activated termite feces a low-cost adsorbent for the adsorption of norfloxacin from aqueous solution

Antibiotics, as emerging contaminants, are of global concern due to the development of antibiotic resistant microorganisms. Current wastewater treatment technology cannot efficiently remove sewage antibiotics and therefore new low-cost technologies are needed. Adsorption is a widely used process for removal of substances, and the search for efficient, low-cost adsorbents is ongoing. In this work, termite feces treated with H₂SO₄ (FT/H₂SO₄) were used as a low-cost adsorbent for removal of norfloxacin (NOR) present in aqueous medium. Termite feces were treated with H₂SO₄ at a ratio of 1:1 for 24 h, at 100 °C. The parameters contact time, initial NOR concentration, medium pH and temperature were evaluated. The optimum adsorption pH was 8.0. The pseudo-second-order model was found to best represent the kinetics of NOR adsorption. The maximum adsorption capacity, calculated from the Sips isotherm model, was 104.4 mg/g at 55 °C. The positive values of ΔH⁰ (change in enthalpy) confirm the endothermic nature of the adsorption. The results show that FT/H₂SO₄ is an efficient adsorbent for removal of NOR present in aqueous medium. The adsorption capacity is higher than those reported in the literature for other low-cost adsorbents.