Optimization and application of walnut shell-driver biochar for efficient removal of salicylic acid from wastewater: Experiment and theoretical study

Magnetic magnesium-zinc spinel ferrite Mg1 - xZnxFe2O4 (where x = 0.4, 0.6, and 0.8) was investigated as adsorbent for the efficient removal of Sr(II) ions and salicylic acid (SA) contaminants from aqueous medium. The characterization of ferrites was carried out using XRD, VSM, BET, SEM, and EDS. The surface charge of magnetic adsorbents was measured by the drift method. The determination of SA and Sr(II) ion concentrations in the solution phase was carried out by UFLC and complexometry, respectively. It was shown that varying of the Zn(II) content affected the adsorption capacities of magnesium-zinc ferrites. The increasing of zinc content from x(Zn2+) = 0.4 to x(Zn2+) = 0.6 increased the adsorption of Sr(II) ions from 50 to 65mg/g, and then it was decreased to 36mg/g for the sample with x(Zn) = 0.8. The Mg0.4Zn0.6Fe2O4 sample demonstrated the maximum adsorption capacity of 74mg/g. The adsorption isotherm for Sr(II) was fitted by the Dubinin-Radushkevich, Langmuir, Freundlich, and Sips models. The adsorption kinetics of Sr(II) was analyzed by PFO, PSO, and Elovich models. The adsorption kinetics of SA was also investigated. It was demonstrated that the Mg0.2Zn0.8Fe2O4 sample exhibited 90% removal of salicylic acid from the water solutions. The results demonstrated that magnetic Mg-Zn ferrites with spinel structure are good sorbents for the removal of SA and Sr(II) ions from aqueous solution.

When driving an automobile today the reliable function of the total system under various environmental conditions has become a matter of course. Experimentation and theoretical studies since 1886 have led to the automobile of today. The “functioning” of the dynamic system motor vehicle, — whether it is comfortable, easy to handle, racy, etc., can be explained by the interaction of the sub-systems. For example the engine and the drive train provide the energy for forward motion while the suspension systems are responsible for comfort and wheel guidance. The goal of this paper is to explain the dynamics of a vehicle as a connection of subsystems based on theoretical and experimental studies. The emphasis is placed on the motion of a passenger car on an even, dry roadway within the normal driving range.

Forced convection transient heat transfer for helium gas at various periods of exponential increase of heat input (Q0exp(t/τ)) to a horizontal cylinder (heater) was theoretically and experimentally studied. In the theoretical study, transient heat transfer was numerically solved based on a turbulent flow model. It was clarified that the surface superheat and heat flux increase exponentially as the heat generation rate increases with the exponential function. The values of numerical solution for surface temperature and heat flux agree well with the experimental data for the cylinder diameter of 1mm. In the experimental studies, the authors measured heat flux, surface temperature, and transient heat transfer coefficients for forced convection flow of helium gas over horizontal cylinders under wide experimental conditions. The platinum cylinders with diameters of 1.0mm, 0.7mm, and 2.0mm were used as test heaters. The gas flow velocities ranged from 2 to 10m/s, and the periods ranged from 50ms to 15s. It was clarified that the heat transfer coefficient approaches the quasi-steady-state one for the period τ longer than about 1s, and it becomes higher for the period shorter than around 1s. The heat transfer shifts to the quasi-steady-state heat transfer for longer periods and shifts to the transient heat transfer for shorter periods. The transient heat transfer coefficients show significant dependence on cylinder diameters, there are higher for smaller cylinder diameters. The empirical correlations for quasi-steady-state heat transfer and transient heat transfer were obtained based on the experimental data.

Pharmaceuticals such as salicylic acid are commonly detected in wastewater and surface waters, increasing concern for possible harmful effects on humans and the environment. Their difficult removal via conventional treatments raised the need for improved strategies, among which the development of bioderived adsorbents gained interest because of their sustainability and circularity. In this work, biobased cross-linked adsorbents, synthesized via a sustainable approach from starch derivatives, namely beta-cyclodextrins and maltodextrins, were at first characterized via FTIR-ATR, TGA, SEM, and elemental analysis, showing hydrophilic granular morphologies endowed with specific interaction sites and thermal stabilities higher than 300 °C. Subsequently, adsorption tests were carried out, aiming to assess the capabilities of such polymers on the removal of salicylic acid, as a case study, from water. Batch tests showed rapid kinetics of adsorption with a removal of salicylic acid higher than 90% and a maximum adsorption capacity of 17 mg/g. Accordingly, continuous fixed bed adsorption tests confirmed the good interaction between the polymers and salicylic acid, while the recycling of the adsorbents was successfully performed up to four cycles of use.

Removal of salicylic acid by electrochemical processes using stainless steel and platinum anodes

Electrochemical removal of salicylic acid from aqueous solutions using aluminum electrodes

Ion cum molecularly dual imprinted polymer (DMIP) was synthesized for the simultaneous removal of salicylic acid (SA) and cadmium (Cd) by suspension polymerization method using chitosan (CTS) as functional polymer, epichlorohydrin as cross-linker, and 4-hydroxy benzoic acid (4HBA) as well as Cd as organic and inorganic templates, respectively. Use of the dummy template 4HBA during the synthesis of DMIP had the advantage of creating imprinted cavities in DMIP, which depicted good uptake for SA. Scanning electron microscopy and Fourier transform infrared spectroscopy indicated successful preparation of DMIP. Particle size analysis confirmed polydispersity, and thermal and swelling studies indicated the mechanical stability in DMIP. The rebinding capacities of the DMIP for Cd and SA were found to be 38.46 and 23.81mgg-1 , respectively, under the optimize condition of the time, dose, and concentration. Adsorption isotherm results fitted into Langmuir adsorption isotherm model with the R2 values of 0.994 and 0.995 for Cd and SA, respectively. The presence of intramolecular hydrogen bonding in SA, stability of the template-monomer complexes (CTS-SA and CTS-4HBA), and the involvement of the hydroxyl groups on DMIP for the uptake of SA has been supported by molecular modeling studies using Gaussian 03 software. The electron doublet of the amino groups of DMIP was involved for the uptake of Cd. Lower binding efficiency of DMIP for SA as compared to Cd may be due to the partial participation of hydroxyl group in cross-linking with epichlorohydrin during the synthesis of DMIP.

In the present research, new carbon nanosorbents were developed for removal of salicylic acid (SA) in aqueous media. The starting materials were graphene flakes with thicknesses of 12 nm (C12) and 60 nm (C60) subjected to covalent functionalisation in a reflux reactor using different chemical reagents (HNO3,H2SO4, NaOH and KOH) at 353 K for 4 h. Characterisation work revealed that the specific surface areas of C12 and C60 were 68.74 and 9.76 m2/g, respectively. The capability of the prepared nanosorbents in SA sequestration was examined using batch adsorption system. The results suggested that C12 treated withH2SO4 (C12-H2SO4) exhibited the highest percentage removal of SA (55 %). FTIR analysis showed the presence of various functional groups viz. hydroxyl, alkyne, amine, carboxylic acid, carbonyl, alcohol and alkyl halide on C12-H2SO4 which might have interacted with SA. The adsorption equilibrium was evaluated by varying the initial SA concentration. Experimental data were analysed by Langmuir, Temkin and Dubinin-Radushkevich (D-R) and Freundlich models. The goodness-of-fit of the models was determined by Marquardt’s percent standard deviation, chi-square, average relative error and sum of absolute error with model parameter optimisation evaluated by sum of normalised errors (SNE). It was found that D-R model was the best fit model with the lowest SNE. The primary results showed that chemical functionalisation has been successfully used for attaching specific functional groups onto C12. In addition, the new graphene- based nanosorbent viz. C12-H2SO4 has a great potential application for SA removal.

Synthesis, characterization and adsorption properties of diethylenetriamine-modified hypercrosslinked resins for efficient removal of salicylic acid from aqueous solution

Highly efficient removal of salicylic acid from pharmaceutical wastewater using a flexible composite nanofiber membrane modified with UiO-66(Hf) MOFs

Application of biochar, a pyrolyzed biomass from organic sources, to agricultural soils is considered a promising strategy to sustain soil fertility leading to increased plant productivity. It is also known that applications of biochar to soilless potting substrates and to soil increases resistance of plants against diseases, but also bear the potential to have inconsistent and contradictory results depending on the type of biochar feedstock and application rate. The following study examined the effect of biochar produced from maple bark on soybean resistance against Rhizoctonia foliar blight (RFB) disease caused by Rhizoctonia solani, and examined the underlying molecular responses of both soybean and R. solani during interaction with biochar application. Soybean plants were grown in the presence of 1, 3, or 5% (w/w) or absence of maple bark biochar for 2 weeks, and leaves were infected with R. solani AG1-IA. At lower concentrations (1 and 3%), biochar was ineffective against RFB, however at the 5% amendment rate, biochar was conducive to RFB with a significant increase in disease severity. For the first time, soybean and R. solani responsive genes were monitored during the development of RFB on detached leaves of plants grown in the absence and presence of 5% biochar at 0, 6, 12, and 24 h post-inoculation (h.p.i.). Generally, large decreases in soybean transcript abundances of genes associated with primary metabolism such as glycolysis, tricarboxylic acid (TCA) cycle, starch, amino acid and glutathione metabolism together with genes associated with plant defense and immunity such as salicylic acid (SA) and jasmonic acid pathways were observed after exposure of soybean to high concentration of biochar. Such genes are critical for plant protection against biotic and abiotic stresses. The general down-regulation of soybean genes and changes in SA hormonal balance were tightly linked with an increased susceptibility to RFB. In conjunction, R. solani genes associated with carbohydrate metabolism were up-regulated, while genes involved in redox reactions and detoxification had varying effects. In conclusion, this study presents strong evidence that maple bark biochar increased susceptibility of soybean to a foliar disease. This condition is partly mediated by the down-regulation of soybean genes leading to reduced immunity and also affecting R. solani gene expression.

nanosized copper thin film was prepared on glass substrates by magnetron sputtering. 800 nm pump and 400nm probe technique were used to measure time-resolved reflectivity of copper thin film, and the heat transport processes of copper film were experimentally studied. Thermal transport processes in the copper film were numerically simulated by using Parabolic Two-Step (PTS) model with Finite Difference method. The result of the PTS model can well evaluate the measure date.

Transient analysis of Ghana Research Reactor-1 using PARET/ANL thermal–hydraulic code

Infrared spectral transmission, reflection and thermal emission from diffraction gratings with differing periods, groove widths and groove depths were experimentally and theoretically studied. The structural dimensions are comparable to the measured spectral wavelengths in the range 2.5 to 25 microns. For calculating the optical properties (transmission and reflection spectra), we have used an in-house S-Matrix Propagation Algorithm (SMPA) technique which is unconditionally stable versus changes in structural dimensions, optical constants and truncation order. We have experimentally studied the planar angular transmission and reflection spectrum of Si and GaAs grating samples, using FTIR spectrometry over the spectral range from 2.5 μm to 25 μm. At λ < Λ, the transmitted intensity is quasi-periodic with respect to wave number. A similar property also appears in the reflection spectra. The theoretical results for spectral transmission are in good agreement with the experimental results for the wavelength range 2.5 to 25 μm.

Characterization and utilization of activated carbons prepared from coffee residue for adsorptive removal of salicylic acid and phenol: Kinetic and isotherm study