EMPLOYMENT OF NON-CONVENTIONAL MATERIAL IN PURIFICATION OF CONTAMINATED AQUEOUS SOLUTIONS

Systematic approach for the optimal process conditions of Reactive Red 198 adsorption by pistachio nut shell using Taguchi method

Pistachio nut shells, an agricultural waste biomass, and Lewatit TP 214, a commercial sorbent, were investigated as adsorbents for the adsorption of platinum from dilute hexachloroplatinic acid solutions. Before the pistachio nut shells were carbonized, adsorption percentage was 65%, whereas Lewatit TP 214 ensured almost 100% adsorption. However, after the pistachio nut shell was carbonized at 1,000° C under an argon atmosphere, the platinum adsorption (%) increased two-fold. The effects of such parameters as sorbent dosage, contact time, temperature and solution pH on adsorption were studied in detail in batch mode. The adsorption equilibrium data were best fitted with the Langmuir isotherm model. The maximum adsorption capacities, Qmax, at 25° C were found to be 38.31 and 33.22 mg/g for the carbonized pistachio nut shell and Lewatit TP 214, respectively. The adsorption of platinum on both sorbents was found to be described by the pseudo-second-order kinetic model. The results indicated that the activated carbon prepared from pistachio nut shells can be effectively used for the removal of platinum from acidic solutions.

Present work investigates platinum uptake from synthetically prepared, dilute platinum-bearing solutions using biomass residues, i.e. pistachio nut shell and rice husk, which are abundant in Turkey, and provides a comparison between these two biosorbents. Effects of the different uptake parameters, sorbent dosage, contact time, temperature and pH of solution on platinum uptake (%) were studied in detail on a batch sorption. Before the pistachio nut shell was activated, platinum uptake (%) was poor compared to the rice husk. However, after the pistachio nut shell was activated at 1000 °C under an argon atmosphere, the platinum uptake (%) increased two-fold. The pistachio nut shell (original and activated) and rice husk were shown to be better than commercially available activated carbon in terms of adsorption capacity. These two sorbents have also been characterized by FTIR and SEM. Adsorption equilibrium data best complied with the Langmuir isotherm model. Maximum adsorption capacities, Qmax, at 25 °C were found to be 38.31 and 42.02 mg.g- 1for the activated pistachio nut shell and rice husk, respectively. Thermodynamic calculations using the measured ∆H°, ∆S° and ∆G° values indicate that the uptake process was spontaneous and endothermic. The experimental data were shown to be fit the pseudo-second-order kinetic model.

Removal of Amoxicillin From Aqueous Solution in Batch and Circulated Fluidized Bed System Using Zinc Oxide Nanoparticles: Hydrodynamic and Mass Transfer Studies

Adsorptive removal of Cu(II) by pistachio shell: Isotherm study, kinetic modelling and scale-up designing — continuous mode

In this study, inexpensive agricultural waste pistachio sells was used for adsorption of violet B. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM) were used to characterize the pistachio shells. The morphology of pistachio shell was studied by SEM and it showed the porous structure of pistachio shells. Different parameters like contact time, pH and mass of sorbent were investigated. The adsorption is dependent on pH of the medium where the removal efficiency increases as the pH turns to 11. The contact time studies showed that 45 min shaking time was sufficient to achieve the equilibrium. The reaction kinetics data were analyzed using two reactions kinetic of pseudo-first-order reaction model and pseudo-second-order reaction model, and it was found that the removal of violet B followed the pseudo-second order reaction model. Keywords: Adsorption, violet B, agricultural waste, pistachio shell. Afr. J. Biotechnol. Vol. 12 No. 50

A new method on producing high surface area activated carbon: The effect of salt on the surface area and the pore size distribution of activated carbon prepared from pistachio shell

In this study, the removal of zinc(II) ion from an aqueous solution by pistachio shells (PS) is investigated. The dynamic behavior of the adsorption is examined on the effects of pH, adsorbent dosage, and contact time. The adsorption rates are determined quantitatively and simulated by the Lagergren first order, pseudo‐second order, Elovich, and intra‐particle diffusion kinetic models. The adsorption kinetic models are also tested for validity. The thermodynamic parameters, which are also deduced from adsorption experiments, are very useful in elucidating the nature of adsorption. The experimental results reveal that the optimum pH value and the contact time for the adsorption of Zn2+ onto PS are found as 6 and 10 min, respectively. According to these parameters, adsorption process follows the pseudo‐second order kinetic model with high correlation coefficients (R2 = 0.999). The obtained results demonstrate that PS is a reasonably effective adsorbent for the removal of Zn2+ from aqueous leachate of hazardous waste.

Potassium hydroxide-activated carbons (CK21, CK11, and CK12) were prepared from pistachio nutshells. Physicochemical properties of activated carbons were characterized by TGA, <TEX>$pH_{pzc}$</TEX>, Fourier transform infrared spectroscopy, scanning electron microscopy, and <TEX>$N_2$</TEX>-adsorption at <TEX>$-196^{\circ}C$</TEX>. The examinations showed that activated carbons have high surface area ranging between 695-1218 <TEX>$m^2/g$</TEX>, total pore volume ranging between 0.527-0.772 mL/g, and a pore radius around 1.4 nm. The presence of acidic and basic surface C-O groups was confirmed. Batch adsorption experiments were carried out to study the effects of adsorbent dosage, temperature, initial concentration of adsorbate, and contact time on deltamethrin adsorption by activated carbons. The kinetic studies showed that the adsorption data followed a pseudo-second order kinetic model. The Langmuir model showed a maximum adsorption capacity of 162.6 mg/g at <TEX>$35^{\circ}C$</TEX> on CK12. Thermodynamic studies indicated that adsorption was spontaneous and increased with temperature, suggesting an endothermic process.

Background and aimFinding a cost-effective adsorbent can be an obstacle to large-scale applications of adsorption. This study used an efficient activated carbon adsorbent based on agro-waste for dye removal. MethodsPistachio shells as abundant local agro-wastes were used to prepare activated carbon. Then, it was modified with iron to improve its characteristics. Acid red 14 was used as a model dye in various conditions of adsorption (AR14 concentration 20–150 mg L−1, pH 3–10, adsorbent dosage 0.1–0.3 g L−1, and contact time 5–60 min). ResultsA mesoporous adsorbent was prepared from pistachio shells with 811.57 m2 g−1 surface area and 0.654 cm3 g−1 pore volume. Iron modification enhanced the characteristics of activated carbon (surface area by 33.3% and pore volume by 64.1%). Adsorption experiments showed the high effectiveness of iron-modified activated carbon for AR14 removal (>99%, >516 mg g−1). The adsorption followed the pseudo-second kinetic model (k = 0.0005 g mg−1 min−1) and the Freundlich isotherm model (Kf = 152.87, n = 4.61). Besides, the reaction occurred spontaneously (ΔG0 = −36.65 to −41.12 kJ mol−1) and was exothermic (ΔH0 = −41.86 kJ mol−1 and ΔS0 = −3.34 J mol−1 K−1). ConclusionIron-modified activated carbon derived from pistachio shells could be cost-effective for the treatment of industrial wastewater containing dyes.

As time progresses, a combination of human activities and natural occurrences releases contaminants, specifically heavy metals. These contaminants enter into water bodies, posing a threat to aquatic ecosystems and emphasizing the importance of implementing effective measures for pollution control and water quality preservation. This makes it necessary to treat water to reduce the negative impacts of toxic heavy metals in water and supply pure water for domestic and environmental use. Thus, the increased release of heavy metals like lead into the environment due to rapid industrialization has raised severe global concerns. This study aims to remove lead ions from water using a low-cost bio adsorbent. The present study examined the utilization of groundnut shells, tamarind pod shells, rubber seed shells, and pistachio shells as lead adsorbents. The adsorption efficiency is examined in relation to adsorbent dose, pH, contact time, and initial concentration, and the most efficient adsorption parameters are identified. In addition, adsorption mechanism, thermodynamics parameters and kinetic modeling are carried out to clarify the mechanism of adsorption. Isometric models, namely, Langmuir and Freundlich, are used to characterize the adsorption process, with better correlation to the Langmuir model. Kinetic observations indicated that adsorption in similar manner with transition of pseudo-second-order model and thermodynamic analysis confirmed the nature of spontaneous exothermic and spontaneous endothermic adsorption reaction. The pistachio shell emerged as the most effective of the four examined adsorbents, displaying the highest adsorption capacity of 88.9% at an adsorbent dosage of 1.2 g/L. This result underscores the superior performance of pistachio shells, positioning it as the optimal choice among the tested adsorbents.

The green synthesis of nickel oxide nanoparticles (NiO-NP) was investigated using Ni(NO3)2 as a precursor, olive tree leaves as a reducing agent, and D-sorbitol as a capping agent. The structural, optical, and morphology of the synthesized NiO-NP have been characterized using ultraviolet–visible spectroscopy (UV-Vis), X-ray crystallography (XRD) pattern, Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM) analysis. The SEM analysis showed that the nanoparticles have a spherical shape and highly crystalline as well as highly agglomerated and appear as cluster of nanoparticles with a size range of (30 to 65 nm). The Scherrer relation has been used to estimate the crystallite size of NiO-NP which has been found about 42 nm. The NiO-NPs have subsequently used as adsorbents for adsorption of two types of dyes; methylene blue (MB) as cation dye and methyl orange (MO) as anion dye. The removal efficiency of dyes from contaminated water was investigated during various key parameters at room temperature; initial dye concentration (Co), pH, contact time (t), agitation speed, and adsorbent dosage. The maximum removal of MB dye was found to be 96% (Co=25 mg/l, pH=10, contact time=100 min, agitation speed=300 rpm and adsorbent dosage=6 g/l), while for MO the maximum removal reached 88% at (Co=20 mg/L, pH=2, contact time=160 min, agitation speed=300 rpm and adsorbent dosage=6 g/L). The experimental adsorption data were found to well obey Freundlich isotherm. The kinetic investigation showed that the adsorption process for both dyes followed a pseudo-second-order model with rate constants 0.0109 and 0.0079 (mg/g min) for MB and MO, respectively.

Biosorbtive removal of the antibacterial drug, ethacridine lactate (EL), from aqueous solutions was investigated using as biosorbent Saccharomyces pastorianus residual biomass immobilized in calcium alginate. The aim of this work was to optimize the biosorption process and to evaluate the biosorption capacity in the batch system. Response surface methodology, based on a Box–Behnken design, was used to optimize the EL biosorption parameters. Two response functions (removal efficiency and biosorption capacity) were maximized dependent on three factors: initial concentration of EL solution, contact time, and agitation speed. The highest values for the studied functions (89.49%, 26.04 mg/g) were obtained in the following operational conditions: EL initial concentration: 59.73 mg/L; contact time: 94.26 min; agitation speed: 297.57 rpm. A number of nonlinear kinetic models, including pseudo-first-order, pseudo-second-order, Elovich, and Avrami, were utilized to validate the biosorption kinetic behavior of EL in the optimized conditions. The kinetic data fitted the pseudo-first-order and Avrami models. The experimental results demonstrated that the optimized parameters (especially the agitation speed) significantly affect biosorption and should be considered important in such studies.

Two activated carbons were obtained from pistachio shells by impregnation with H3PO4 under standard conditions of acid concentration (50 wt%) and heat treatment at 773 K for 2 h. The soaking time was 24 and 72 h for the two samples before thermal pyrolysis. Analysis of the N2/77 K adsorption isotherms proved that both were highly adsorbing carbons with considerable microporosity, and that the prolonged contact with activant enhanced total porosity (surface area and pore volume) and increased the amount of mesoporosity. Adsorption isotherms of probe molecules, viz methylene blue (MB), rhodamine B (RB), phenol (P) and p‐nitrophenol (PNP), were determined at room temperature, from aqueous solutions. Both the Langmuir and Freundlich model adsorption equations show satisfactory fit to experimental data. Both carbons exhibit similar adsorption parameters irrespective of their porosity characteristics. The sequence of uptake per unit weight was: PNP &gt; MB &gt; RB &gt; P. Low affinity towards phenol may be associated with its competition with water molecules which are more favourably attracted to the acid surface which has a high oxygen functionality. Preferred adsorption in the order PNP &gt; MB &gt; RB is proposed to be a function of carbon porosity, related to the increased molecular dimensions of the solutes. Adsorption from a binary mixture of equal concentrations of MB and RB showed reduced uptake for both sorbates in comparison to the single component experiments. RB removal surpasses that of MB in the binary test and may be attributed to lower water solubility and higher molecular dimensions. Copyright © 2003 Society of Chemical Industry

The study of different renewable energy sources has been intensifying due to the current climate changes; therefore, the present work had the objective to characterize physicochemically the pistachio shell waste and evaluate kinetic parameters of its combustion. The pistachio shell was characterized through proximate analysis, ultimate analysis, SEM, and FTIR. The thermal and kinetic behaviors were evaluated by a thermogravimetric analyzer under oxidant atmosphere between room temperature and 1000°C, in which the process was performed in three different heating rates (20, 30, and 40°Cmin-1). The combustion of the pistachio shell presented two regions in the derivative thermogravimetric curves, where the first represents the devolatilization of volatile matter compounds and the second one is associated to the biochar oxidation. These zones were considered for the evaluation of the kinetic parameters E a , A, and f(α) by the modified method of Coats-Redfern, compensation effect, and master plot, respectively. The kinetic parameters for zone 1 were E a1=84.11kJmol-1, A 1=6.39×106min-1, and f(α)1=3(1-α)2/3, while for zone 2, the kinetic parameters were E a2=37.47kJmol-1, A 2=57.14min-1, and f(α)2=2(1-α)1/2.