Adsorption and Reduction of Aqueous Cr by FeS-Modified Fe-Al Layered Double Hydroxide

To remedy the widespread chromium (Cr) pollution in the environment, this study mainly used the ultrasonic-assisted co-precipitation and precipitation methods to prepare FeS-modified Fe-Al-layered double hydroxide (FeS/LDH) composite material. The experimental results showed that FeS/LDH has higher removal efficiency of Cr in aqueous solution and stronger anti-interference ability than unmodified LDH. Under the same reaction conditions, the removal efficiency of total Cr(Cr(T)) using LDH was 34.85%, and the removal efficiency of Cr(VI) was 46.76%. For FeS/LDH, the removal efficiency of Cr(T) and Cr(VI) reached 99.57% and 100%, respectively. The restoration of Cr(T) and Cr(VI) by FeS/LDH satisfied the Langmuir adsorption isotherm. The maximum adsorption capacity of Cr(T) and Cr(VI) achieved 102.9 mg/g and 147.7 mg/g. The efficient removal of Cr by FeS/LDH was mainly based on the triple synergistic effect of anion exchange between Cr(VI) and interlayer anions, redox of Cr(VI) with Fe2+ and S2−, and co-precipitation of Fe3+ and Cr3+.

Aplikasi Zeolit Alam Aktif Wonosari Sebagai Adsorben Zat Warna Remazol Yellow Fg

Zeolite as an adsorbent has been widely used. Zeolite activation was carried out to increase the absorption. This study aimed to determine the characteristics of the active zeolite and apply it as an adsorbent. The activation process was carried out by adding acid and calcining at 4500C for 6 hours. Remazol Yellow FG is a dye that is widely used in the textile industry. In this study, the adsorption process was carried out on the Remazol Yellow FG solution, then analyzed the effect of changes in pH (5, 6, 7, 8, 9), contact time (30, 60, 90, 120, 150 minutes) and the concentration of Remazol Yellow FG solution ( 50, 100, 150, 200, 250 ppm) on the adsorption of Remazol Yellow FG dye. From the analysis of the sample solution of Remazol Yellow, the values of Ce and qe can be calculated. These values were then used to calculate KL and KF in the Langmuir adsorption isotherm and Freundlich adsorption isotherm models. From the experimental results, it could be seen that as the contact time increased, the adsorption capacity would be greater. However, when the zeolite was already in the saturated phase, the adsorption capacity would tend to decrease. In the Langmuir adsorption isotherm, the KL value was 0.0274 L/mg and in the Freundlich adsorption isotherm model, the KF value was 29.25 L/mg. Remazol Yellow FG adsorption tended to follow the Langmuir adsorption isotherm model with an R2 value of 0.998.

Modification of Sulfonated Polyethersulfone Membrane as a Selective Adsorbent for Co(II) Ions

In the current study, a variety of sulfonated polyethersulfone (SPES)-based ion-exchange membranes were prepared and utilized as efficient and selective solid adsorbents for the detection of Co(II) ions in aquatic solutions. SPES membranes were treated with a variety of cations at a 2:1 ratio overnight. The produced materials were assessed via XRD, FT-IR, SEM, and TGA analyses. The structure of these materials was confirmed by FT-IR and XRD, which also confirmed the inclusion of Na+, NH4+, and amberlite on the SPES surface successfully. TGA analysis showed that the thermal stabilities of these materials were enhanced, and the order of stability was NH4-SPES > SPES > Na-SPES > A-SPES. Furthermore, the efficiency of these modified membranes for the determination and adsorption of a variety of metal ions was also examined by the ICP-OES analytical technique. A-SPES expressed a powerful efficiency of adsorption, and it showed an efficient as well as quantitative adsorption at pH = 6. Moreover, A-SPES displayed the highest adsorption capacity of 90.13 mg/g for Co(II) through the Langmuir adsorption isotherm.

Batch Adsorption Assessment of Neem Nut Carbon for Abating Chromium(VI) in Wastewater

Discharge of Cr(VI) laden effluents is highly toxic and decontaminating the wastewater from Cr(VI) is necessary for Environmental Protection. An investigation on the adsorption characteristics of activated carbon prepared from neem nut (NNC) for the removal of Cr(VI) from wastewater by varying the parameters such as carbon dose, pH, equilibration time by batch studies was found to be effective for the removal of Cr(VI) from wastewater. Carbon characteristics of activated neem nut carbon were ascertained. Evaluation were done by varying the pH from 1 to 6, carbon dose from 0.1 g to 0.5 g and equilibration time from 1 to 6 hours. Maximum Cr(VI) removal of 95% took place when batch studies were done at an optimal pH of 2, carbon dose of 0.2 g//100mL, and equilibration time of 4 hours. Freundlich and Langmuir adsorption isotherm models were considered for analysis.

COVID-19 Vaccine, Contraceptive, Viscosity and Safety Margin Change

The temperature effect of 4-ethyl-1-(4-oxo-4-phenylbutanoyl)thiosemicarbazide (EOPT) on the mild steel corrosion in 1 M HCl solution was studied by gravimetric techniques at temperatures varying from 303 to 333 K. The investigated inhibitor concentrations were started from 100 ppm and ended with 500 ppm. The inhibition efficiency increased with the increase of the concentration of the inhibitor and reached 96.1% with the concentration of 500 ppm at 303 K and decreased to 66.3% at 333 K. Moreover, the inhibition efficiencies decreased with the temperature increase for both acids. Using the Langmuir adsorption isotherm for the adsorption of this inhibitor on the mild steel surface was determined. EOPT was found to be an efficient corrosion inhibitor due to its structural molecules, which contain sulfur, nitrogen, and oxygen, hetero atoms an addition to the aromatic ring.

Preparation of Eco-Friendly Acidic Corrosion Inhibitors from Ilex Chinensis Sims Leaves

Preparing chemicals from natural product is a simple way to green chemistry. May flavonoids and protocatechuic acid have been found in Ilex Chinensis Sims leaves extracts, which indicates its extracts suitable to be used as an effective corrosion inhibitor. Extracts of Ilex Chinensis Sims leaves (HE) were modified with hydroxymethylation reaction and Mannich reaction to produce the relative stable green acidic corrosion inhibitors (HM1 and HM2). The extracts of Ilex Chinensis Sims leaves and the modified samples were investigated on the corrosion inhibition of A3 steel accordingly. The results show that these inhibitors have effective corrosion inhibition effect on A3 steel. The HM2 are the most effective for corrosion inhibition, and the inhibition efficiency can reach to 78.36%. At 60 °C, the corrosion inhibition efficiency of these three extracts is HM2 > HM1 > HE. And the extracts inhibit corrosion mainly by adsorption mechanism. This adsorption accords with Langmuir adsorption isotherm.

Removal of Heavy Metals (Fe, Mn and Cd) from Aqueous Solutions by Natural Zeolite and FeS Media

Objectives : The adsorption characteristics of Fe, Cd, and Mn in aqueous solution using zeolite and FeS media were investigated by the adsorption isotherm and kinetic model analysis.Methods : The adsorption characteristics of the heavy metals (Fe, Mn, Cd) were investigated using Langmuir or Freundlich adsorption isotherm. The analysis of pseudo-first or pseudo-second order reaction was also attempted to evaluate the rate limiting factor such as molecular diffusion or chemical adsorption on the absorbents.Results and discussion : The adsorption of the heavy metals on the zeolite and FeS media was more suitable for the Langmuir adsorption isotherm, representing that mono-layer absorption on the surface and no interaction between the absorbed solutes. The order of adsorption preference to zeolite was Fe > Cd > Mn, whereas the order of adsorption preference to FeS media was Cd > Fe > Mn. The adsorption kinetics of zeolite and FeS media were more suitable for pseudo-secondary reactions than for pseudo-primary reaction.Conclusions : The absorption capacity of FeS media for the heavy metals (Fe, Cd and Mn) in aqueous solution was higher than that of zeolite. The adsorption pattern was suitable for the Langmuir adsorption isotherm, and has kinetic characteristic by chemisorption.

Study on the ability to remove Cd2+ ions in water environment by using halloysite mixture from Thach Khoan area, Phu Tho

Thach Khoan, Phu Tho area is the area with great potential for weathered kaolinite source from pegmatites of the Tan Phuong complex. This kaolin has quite good quality and is used in many traditional applications such as high quality ceramic glaze, high-grade bricks. However, the use of this material in the treatment of water pollution is still limited. In this study, the natural kaolin material from Thach Khoan area, Phu Tho province with about 87% amount of tubular halloysites was used to remove Cd2+ ion from water. The factors of pH, contact time, the adsorbent weight, and initial concentration of Cd2+ were studied to access their effects on the Cd2+ ion adsorption process using this raw material. The results indicated that under the conditions of pH0 of 6.5 and at room temperature (25 oC), with 0.8 g of halloysite powder and Cd2+ initial concentration of 30 mg/L, the adsorption of Cd2+ could reach equilibrium after 50 minutes with an efficiency of 86.31%. The adsorption process follows the Langmuir adsorption isotherm model with the maximum monolayer adsorption capacity of 2.75 mg/g and follows the second-order pseudo-adsorption kinetic equation. The results show that the natural halloysite material without treatment has the potential in using to remove heavy metal ions in polluted water and needs to be studied further.

Artichoke Extract as an Eco-Friendly Corrosion Inhibitor for Zinc in 1 M Hydrochloric Acid Solution

Artichoke extract (AE) was studied as the corrosion inhibitor for zinc in 1 M HCl utilizing chemical and electrochemical methods. The adsorption isotherm of Artichoke extract on Zn surface accords with Langmuir adsorption isotherm. The inhibition efficiency increases with increasing the extract's concentration and decreases with the rise in the medium's temperature. The inhibition efficiency reached a value of 93.2% at 300 ppm of extract. This extract may be forming a film and acts as a barrier, which minimizes the contact area between zinc surface and HCl solution. Artichoke extract acts as a mixed inhibitor in HCl solution. Thermodynamic parameters of activation and adsorption were determined and explained. The adsorption parameters also obeyed the Langmuir adsorption isotherm, and the sign of the free energy of adsorption showed a spontaneous process. The surface morphology of zinc metal was examined by employing various techniques. Also, the biological effect of the Artichoke extract was studied. Theoretical studies of quantum mechanics and molecular dynamics simulations studies were carried out on the Artichoke extract compounds, and the results agree with the experimental one. The efficiencies marked from all employed techniques were in perfect correspondence, demonstrating the validity of these procedures.