Freundlich Adsorption Equation Research Articles

Adsorption characteristics and applications of andesite in removing some pollutants from wastewater

Andesite was employed to effectively extract mercury(II) in an aqueous solution. After evaluating its characteristics, andesite was characterized by applying modern techniques such as BET and TGA methods. The study employed SEM and TEM measurements to analyze the variation in the surface shape and crystallinity of the metal due to adsorption. Using the EDX process, the chemical composition, weight, and atomic percentage of each element of andesite were determined. FTIR techniques were also used to confirm the TEM–EDX findings. Zeta potential was estimated. Cycles of regeneration and desorption have been examined. 99.03% was the highest uptake percentage. Adsorbent quantity (0.0025–0.05) g/L, contact time (5–60) min, pH (2–10), temperature (25–60) °C, and dose (0.0027, 0.0044, 0.0125, 0.0155, and 0.0399) mg/L all affect the amount of removal that increases with the increase in contact time, pH, dose, and temperature but drops as the metal ion concentration rises. The ideal values for contact time, pH, metal ion concentration, dose, and temperature were found to be, respectively, 30 min, 0.0155 mg/l, 0.02 g/l, and 40 °C. The calculation of thermodynamic parameters, including ΔH, ΔG, and ΔS, was imperative in establishing that the mechanism of heavy metal adsorption on andesite was endothermic, exhibiting a physical nature that escalated with temperature rise. The Freundlich adsorption equation's linear form is matched by the adsorption of mercury(II) on andesite; constant n was 1.85, 1.06, 1.1, and 1.1, whereas the Langmuir constant qm was found to be 1.85, 2.41, 3.54, and 2.28 mg/g at 25–60 °C. Furthermore, adsorption follows a pseudo-second-order rate constant of (3.08, 3.24, 3.24, and 13) g/mg/min under identical temperature conditions, as opposed to a first-order rate constant of 4, 3, 2.6, and 2. Hg2+, NH4+, Cl−, Br−, NO3−, SO42−, Na+, K+, H2S, and CH3SH were all extracted from wastewater by this application.

Synergistic adsorption and kinetic studies of heterostructured g-C3N4/TiO2 nano-photocatalyst under visible light for enhanced CO2 reduction.

Graphitic carbon nitride (g-C3N4) and titanium dioxide (TiO2) were synthesized using sol-gel and ultrasonic impregnation technique followed by calcination for photocatalytic CO2 reduction. The nano-photocatalysts were analyzed for their morphological, structural, and optical characteristics. Scanning electron microscopy (SEM) revealed the presence of spherical and layered sheet-like nanoparticles, as well as the occurrence of minor aggregations. The ultraviolet-visible spectroscopy (UV-vis) revealed that g-C3N4 has good photocatalytic properties with a medium band gap (2.7eV), and TiO2 has high charge transfer potentials, robust oxidation properties, and high band gap (3.20eV). However, the larger band gap makes it unresponsive in the visible light spectrum. In order to circumvent this constraint, a hybrid heterostructured g-C3N4/TiO2 catalyst with different compositions, viz., 1:1, 1:2, and 2:1, were fabricated using the ultrasonic impregnation technique followed by calcination process. The optical band gap of g-C3N4/TiO2 nanocomposite shows a red shift towards 2.85eV from 3.20eV for bare TiO2, inferring enhanced absorption in the visible light region. Further, the photocatalytic experiments were performed using visible light sources for all the catalysts. The g-C3N4/TiO2 (2:1) reported higher photocatalytic activity due to its reduced crystallite size of 12.94nm which were investigated using X-ray diffraction analysis (XRD) and lower band gap of 2.85eV. The study infers that hybrid photocatalyst enhances the visible light absorption, electron-hole (e - /h +) pair separation rate, and photocatalytic reduction of CO2. In addition, two adsorption models Langmuir and Freundlich were used and adsorption kinetic data were fitted to pseudo-first-orderreaction for all thefive catalysts. The adsorption isotherm of CO2 by g-C3N4/TiO2 (2:1) wellfitted by the Freundlich adsorption equation. On the basis of adsorption magnitude (n) values (1.74), it was found that the interaction between CO2 molecules and g-C3N4/TiO2 occurs according to the chemisorption mechanism. The kinetic study infers that the highest value of apparent rate constant (kapp) was exhibited by g-C3N4/TiO2 (2:1), which indicates that the products predominate at equilibrium.

Numerical analysis of two-bed adsorption thermophysical battery

Air conditioning systems powered by waste energy sources, such as solar-driven adsorption air conditioning systems, hold significant importance. The present study delves into the performance assessment of a silica gel-based adsorption thermophysical battery (ATB) under varying operational conditions. Advanced cycles featuring a two-bed configuration have been devised to enable semi-continuous operation and refrigeration. This novel design presents a compact ATB that integrates the evaporator and condenser within a single heat exchanger, referred to as the Evaporator-Condenser Unit (ECU), thereby reducing the overall size and cost of the ATB system. The operating and design characteristics of the two-bed adsorption system were thoroughly explored using a theoretical model developed through MATLAB software. Evaluations were conducted on various performance metrics of the ATB, encompassing the coefficient of performance (COP), cooling capacity, specific cooling power, adsorption isotherm, and kinetics. A theoretical approach was formulated using the lumped parameter (LPM) and modified Freundlich adsorption equations. It can be deduced that the inlet temperature of the hot coolant exhibited a direct proportion with both refrigeration effect (RE) and specific cooling power (SCP) while inversely affecting the coefficient of performance (COP). A decrease in coolant temperature from 313 to 303 K resulted in a noteworthy 13.4 %. Furthermore, it was observed that COP exhibited a direct proportionality with the flow rate of chilled and cooled water while inversely relating to the flow rate of hot water.

Adsorption of fluoride from water using Al–Mg–Ca ternary metal oxide-coated sand

Abstract An aluminum–magnesium–calcium-coated sand (AMCCS) sorbent was evaluated as a low-cost ternary metal oxide adsorbent for adsorption and removal of fluoride from water with potential application in flow-through water filtration systems. The AMCCS sorbent coating contained mostly amorphous oxides of aluminum, magnesium, and calcium. The adsorption of fluoride occurred in less than an hour, while fluoride adsorption followed pseudo-second-order kinetics. The favorable adsorption of fluoride onto the AMCCS sorbent occurred according to the Langmuir and Freundlich adsorption equations, whereas the physical adsorption of fluoride onto the AMCCS sorbent occurred based on the Dubinin–Radushkevich adsorption equation. The adsorption of fluoride occurred over a broad pH range from 2 to 10.5 with a decrease in adsorption at pH above 10.5, indicative of the adsorption of fluoride onto the positively charged surface of AMCCS sorbent at pH below the AMCCS sorbent pHPZC of 10.4. The AMCCS sorbent was able to remove fluoride from natural waters with appreciable alkalinity, total hardness and total dissolved solids, indicative of AMCCS sorbent selectivity for fluoride adsorption. The AMCCS sorbent was re-coated and reused after several adsorption cycles, rendering the AMCCS sorbent a recyclable and sustainable adsorbent for effective and rapid removal of fluoride from water.

Mercaptan adsorption for desulfurization using a batch microprocess

ABSTRACT In this study, a batch microprocess was developed for the adsorption of ethanethiol from petroleum gas (LPG), liquefied at −45 °C. This process involved microdevices with ZSM-5 zeolite covalently immobilized on the walls of the microchannels. The results indicated the effective removal of the thiol from the liquefied synthetic feed using the microprocess at short contact times. For instance, the thiol concentration of less than 0.005 mg EtSH/g feed was achieved at a contact time of 3 min for the initial thiol concentration of 0.5 mg EtSH/g feed. The ability of the microprocess to remove the thiol from LPG was investigated at different contact times, surface-to-volume ratios of microchannels, and initial thiol concentrations. The thiol removal significantly increased with prolonging the contact time. The effect of time, however, disappeared at long contact times. The thiol removal also showed an ascending trend by increasing the ratio. Furthermore, a phenomenological model was proposed to address the dynamics of the thiol removal. Accordingly, the dynamics was governed by the thiol diffusion toward the immobilized zeolites. In addition, the Freundlich adsorption equation was found to model well the experimental data under equilibrium conditions. Finally, a model was proposed for the operation of the microprocess.

Reusing sludge from surface water treatment plant for hexavalent chromium adsorption in aqueous solution

Contaminants in plating wastewater are hard to remove, especially hexavalent chromium ions. This waste stream contains a large amount of Cr6+, a highly toxic metal, potential to cause cancer. To reduce this pollution, sludge from a supply water treatment plant (DWTS) has been used to make adsorbent. This sludge was denaturized by thermal method. After that, a plating synthetic waste stream contained Cr6+ was treated by a batch adsorption model with adsorbent made from DWTS. pH, amount of adsorbent, and treatment time were investigated to determine the suitable treatment conditions. The study was also evaluated the suitability of two adsorption models Langmuir and Freundlich. Results showed that, under the conditions of pH = 6.0, the adsorbent content of 25.0 g/l, after 90.0 minutes, Cr6+ content remained 0.14 mg/l, close to QCVN 40:2011/BTNMT, column B. The parameters of the Langmuir and Freundlich adsorption equations are: qmax = 12.578 mg/g; Kads = 0.747 l/mg; n = 0.338; kf = 5.138. The Freundlich isothermal model is better fitted to the chromium adsorption process than Langmuir isothermal model.

Adsorption and physicochemical release of iron ions in soils with different content of Calcium Carbonate and Calcium Sulfate

Three soils of different content of gypsum and lime were selected, the first soil (G1) and the second soil (G3), were obtained near the fields of the Faculty of Agriculture, Tikrit University. As for the third soil (G5), was taken from the AL- alam Village side east of Tikrit city to a depth of (0-10)cm. the proportions of gypsum were 5%, 15%, 25%, and the proportions of lime were 25%, 20%, and 10% for soils G1, G3, and G5, respectively. Ferrous sulfate was added as a source of iron ions added to the three soils in the following proportions (0,10,25,50,100,150,250,500,750) mg.L-1 The concepts of isotherm were tested by using the physicochemical Freundlich and Langmuir adsorption equations. The results of the study showed the success of both equations in describing of iron ion adsorption process for all three soils, because They achieve a high (R2) but Langmuir's equation showed a greater superiority due to its decreasing (SE). As it appears from the results of the study, the superiority of treatment (G1) over treatments (G3) and (G5) in the maximum adsorption values, binding energy, (PBCFe)(KG) and (Kd) for adsorption and release. As for the values of Labale iron, the lowest value was in treatment (G1)then it began to increase until it reached its value in treatment (G5). The (Δf) values for the three soils were positive, and that the highest value was in soil (G1), and starts declining to reach its value for soil (G5).

Aggregation‐dependent phosphorus adsorption under different land uses of district Kupwara of Kashmir Valley

AbstractBackgroundPhosphorus (P) is among the essential elements for plant growth and one of the main elements of fertilizers. Decreased availability of P may limit agricultural production in the coming years. The magnitude of soil aggregation influences phosphorus access to mineral surfaces.AimThe present study aims to determine phosphorus adsorption processes affected by soil aggregation under different land‐use systems.MethodsThe distribution of soil aggregates was determined in representative soil samples in the district Kupwara of Kashmir Valley in India. To predict the phosphorus fertilizer requirement of a particular soil, we used the Freundlich adsorption equation and Langmuir equation and drew a clear comparison between these two models.Results and discussionMaximum phosphorus (P) adsorption was recorded at the smallest aggregate size, 0.5–0.1 mm. However, soil aggregates >2.0 mm (the largest category) adsorbed the least amount of P. Our results revealed that increasing the addition of P to the soil decreased the percentage of adsorbed P regardless of aggregate size. The maximum P adsorption of different size aggregates varied between 1869–1924, 1872–1900, 1718–1739, and 1800–1890 mg P kg–1 in irrigated agriculture, forest, orchard and rainfed agriculture soils, respectively. The variation in P adsorption parameters across the different land uses was attributed to their mean weight diameter difference. The maximum bonding energy in the forest resulted in higher P adsorption. Langmuir and Freundlich's adsorption equations were fitted to each soil aggregate size and land‐use system.ConclusionOur results revealed that for all soil aggregate sizes and land use systems, the Freundlich adsorption equation performs better than the Langmuir equation.

The Removal of Atrazine and Benalaxyl by the Fly Ash Released from Kosovo A Power Plant.

The development of low-cost adsorbent coal FA (Kosovo A) for pesticide removal is an important area of scientific research. With this study, we show the potential of adsorption of coal FA (Kosovo A) for the removal of benalaxyl and atrazine from water. We have found that the amount of adsorbed benalaxyl and atrazine increases with an increasing amount of coal FA (Kosovo A) in solution. The maximum capacity coal FA (Kosovo A) to adsorb benalaxyl and atrazine was found to be 0.46 and 0.45 mg/g according to the Freundlich equation and 3.48 and 3.33 mg/g according to the Langmuir equation. The Freundlich adsorption equation better explains the adsorption results of pesticides (benalaxyl and atrazine) in coal FA (Kosovo A), as the values of the recovery coefficient (R2) were higher in Freundlich equation than the Langmuir equation. The adsorption isotherms were of type L and show that the adsorption efficiency of the coal FA (Kosovo A) depends on the initial concentration of benalaxyl and atrazine in solution and the maximum removal of benalaxyl and atrazine was achieved at concentrations less than 10 µg/ml. This study's results are expected to have implications for the use of coal FA (Kosovo A) for the removal of pesticides from water.

Removal of chromium from water using manganese (II, III) oxides coated sand: adsorption and transformation of Cr(VI) and Cr(III)

ABSTRACT A manganese coated sand (MCS) sorbent containing manganese (II,III) oxides was developed for adsorption and transformation of chromium [Cr(VI) and Cr(III)] with potential application in flow-through permeable media adsorption filters. Characterization of the MCS sorbent using XRD and XPS showed that the oxides of manganese (II) and manganese (III) were present on the MCS sorbent surface. Adsorption of both Cr(VI) and Cr(III) onto the MCS sorbent occurred over a broad pH range from 3 to 10. Surface charge analysis of the MCS sorbent determined a pHPZC of 7.8, which may facilitate the uptake of both oxy-anionic Cr(VI) species and cationic Cr(III) species. Favorable adsorption of Cr(VI) and Cr(III) onto the MCS sorbent occurred according to the Langmuir and the Freundlich adsorption equations, with a higher adsorption capacity for Cr(III) than Cr(VI). Adsorption parameters from the Langmuir, the Freundlich and the Temkin adsorption equations showed a stronger binding of Cr(VI) than Cr(III). Adsorption of Cr(III) decreased with increasing calcium concentration while adsorption of Cr(VI) decreased with increasing concentration of common anions found in natural water in the following order: phosphate > sulfate> bicarbonate. Transformation of chromium occurred on the surface of the MCS sorbent due to the partial reduction of Cr(VI) and the partial oxidation of Cr(III), which may be attributed to the role of surface manganese (II,III) oxides as either reducing or oxidizing agents. The MCS sorbent is a recyclable and sustainable adsorbent for removal of chromium from water with an environmental impact comparable to ion-exchange technology.

Adsorption Characteristics and Molecular Simulation of Malachite Green onto Modified Distillers’ Grains

Adsorbent material was prepared using distillers’ grains (DG), which is a waste product of distilleries. The DG was pre-treated with NaOH and esterification-modified with CS2, which is a commonly used anionic modifier. The structure and morphology of the adsorbent was characterized by FTIR, XRD, EDS, SEM, BET, and zeta potential. The related mechanism of adsorption of malachite green (MG) onto modified distiller’s grains (MDG) was studied by adsorption experiments and molecular simulation techniques. The experimental results showed that CS2 successfully modified the DG fiber, and simultaneously yielded the MDG with a uniform pore distribution. MDG had a considerable adsorption capacity of 367.39 mg/g and a maximum removal rate of 96.51%. After eight adsorption–desorption cycle experiments, the adsorption removal rate of MDG to MG dye remained at 82.6%. The adsorption process could be fitted well by a pseudo-second-order kinetic model (the correlation coefficient R2 > 0.998) and Freundlich isotherm adsorption equation (the correlation coefficient R2 > 0.972). Moreover, the adsorption of MG dye by MDG is a spontaneous, endothermic, and increased entropy process. The results of molecular simulation showed that the mechanism of MG molecules onto MDG was mainly chemical adsorption. The adsorption performance of MG onto MDG was better and more stable than DG. Molecular simulation also provided a theoretical guidance of MDG adsorption–desorption for the research on recycling of DG resources.

Adsorption of Fluoride from Water Using Aluminum Coated Sand: Kinetics, Equilibrium, Effect of pH, and Coexisting Ions

An aluminum coated sand (AlCS) was evaluated as a metal oxide adsorbent for adsorption and removal of fluoride from water using a low-cost adsorbent with potential application in continuous flow adsorber systems. Surface characterization of the AlCS sorbent was performed using TEM, SEM/EDX, XRD and BET. The AlCS sorbent contained mostly amorphous aluminum oxides based on adsorbent characterization results. Favorable adsorption of fluoride onto the AlCS sorbent occurred according to the Langmuir and Freundlich adsorption equations, while physical adsorption of fluoride onto the AlCS sorbent was observed based on results from the Dubinin-Radushkevich equation. Fluoride adsorption onto the AlCS sorbent followed pseudo-second order kinetics, while surface charge analysis indicated a pHPZC of 7.1 for the AlCS sorbent. Effective fluoride removal occurred over a broad pH range from 3 to 11 with a maximum fluoride removal observed at pH 4 to 5. The effect of co-existing ions in water resulted in a decrease in fluoride uptake in the presence of bicarbonate, while resulting in an increase in fluoride uptake in the presence of calcium. The AlCS sorbent was a low-cost and sustainable adsorbent for effective adsorption and rapid removal of fluoride from water within an hour.

Iraqi porcelanite Rocks for Efficient Removal of Safranin Dye from Aqueous Solution

This research includes a study of the ability of Iraqi porcelanite rocks powder to remove the basic Safranine dye from its aqueous process by adsorption. The experiments were carried out at 298Kelvin in order to determine the effect of the starting concentration for Safranin dye, mixing time, pH, and the effect of ionic Strength. The good conditions were perfect for safranine dye adsorption was performed when0.0200g from that adsorbed particles and the removal max percentage was found be 96.86% at 9 mg/L , 20 minutes adsorption time and at PH=8 and in 298 K. The isothermal equilibrum stoichiometric adsorption confirmed, the process data were examined by Langmuir, Freundlich and Temkin adsorption equations at different temperatures (298-338)K.The results of the adsorption were good suited for Freundlich and Langmuir Isotherm more than Temkin. Thermodynamic data found for adsorption processes ΔG0, ΔH0, ΔS0 indicates this is the removal step is through the adsorption operations which is spontaneity, exothermic and indicates a decrease in the randomness of that adsorbed dye molecules. Isotherms obtained from the experiments were identical to (S-curve) in form at Giles' discretion.

Removal Studies of S2- Based on SBA-15- Pb(II) Composite

SBA-15 nano mesoporous molecular sieve was successfully synthesized by hydrothermal method and after its adsorption of Pb2+ the prepared material was used to adsorb S2- from aqueous solution. The surface and pore structure of SBA-15, the (SBA-15)-Pb(II) and the composite material of S2- adsorbed by the (SBA-15)-Pb(II) were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and low temperature nitrogen adsorption-desorption isotherm. The effects of solution acidity, S2- concentration, contact time and temperature on the adsorption of S2- by the (SBA-15)-Pb(II) were investigated. The optimized adsorption conditions were obtained. The adsorption rate for S2- by the (SBA-15)-Pb(II) reached 96.33 %. The change of Gibbs free energy in the adsorption process, , can judge that the adsorption process is spontaneous. The enthalpy change in the adsorption process is less than zero, showing that the adsorption process is exothermic reaction. The negative value of entropy change indicates that the adsorption process is a process of entropy reduction. The adsorption of S2- by the (SBA-15)-Pb(II) belongs to the pseudo-second-order kinetics. Freundlich isothermal adsorption equation can better describe the adsorption process. A novel method has been developed to adsorb S2- from wastewater.

Performance evaluation of adsorption thermophysical battery for air conditioning applications

The energy demand in HVAC utilization has been steadily increasing, specifically in warm climate countries such as Iraq. Therefore, searching for advanced air conditioning systems driven by waste energy sources such as adsorption air conditioning systems operated by solar energy becomes necessary. The objective of the present study is to investigate the performance of the adsorption thermophysical battery (ATB) employed with the silica gel-water under various operating conditions. In addition, examine and analyses the influence of outlet chilled temperature and pressure during the charge and discharge processes. The performance parameters of ATB including, cooling capacity (CC), coefficient of performance (COP), specific cooling power (SCP) under different effective temperatures are evaluated. The lumped parameter method (LPM) and modified Freundlich adsorption equations are used to develop a theoretical approach. The results revealed that, relatively low temperature range (50–70 °C) can be used during the charging process based on a common waste heat source. A significant reduction in the temperature and pressure of ECU during the charging-condensation process can be achieved by decreasing the inlet coolant temperature to the chilled temperature. This relatively low temperature is close to the chilled water temperature which can be used for air conditioning purposes. Investigating three inlet chilled temperatures 15 °C, 20 °C, and 30 °C showed that the increase in the chilled temperatures enhanced the evaporation process and increased COP, SCP, CC and the adsorption uptake. The reduction in the inlet coolant temperature from 40 to 20 °C, resulted in 11% enhancement in CC. The determined performance parameters of the ATB system under specified operating conditions are 2 kW, 0.3 and 100 Wkg−1 for CC, COP, and SCP respectively.

ADSORBSI ZAT WARNA ALAMI BUAH MANGROVE JENIS RHIZOPHORA STYLOSA DAN KULIT KAYU TINGI KE DALAM KAIN DENGAN PENGUNCI TUNJUNG DAN TAWAS

<p>The textile industry in Indonesia is growing rapidly, this is confirmed by data from the Badan Pusat Statistik (BPS) which shows that the production of the clothing industry has experienced a significant growth of 15.29 percent in 2019. The use of textile dyes will cause waste problems in the environment. So we need natural dyes as a safer and environmentally friendly alternative. The purpose of this study was to obtain data analysis and to determine the adsorption equilibrium value of the natural dye solution of mangrove <em>Rhizophora stylosa</em> and tingi bark with variations in the amount of dyeing in primisima cloth by comparing it with the Langmuir and Freundlich equations and knowing the role of tunjung and alum in the process of fixing dyes into cloth. This study used a solid-liquid extraction method and then tested by spectrophotometry to obtain initial concentration data. Next, pour the dye that has been tested for its tannin content into a measuring cup and insert the cloth as a medium for mass transfer of tannins from liquid to solid. Samples were taken for each dyeing and tested for tannin content by spectrophotometry and the Ca value was obtained. Isotherm pattern testing. The adsorption test for the absorption process of tannins in natural dyes by cloth was carried out by calculating using the Langmuir and Freundlich equation. Furthermore, the cloth that has been dyed is fixed by tunjung and alum.The most suitable determination of the adsorption capacity of the cloth against natural dyes <em>Rhizopora stylosa</em> and tingi bark is by using the Freundlich adsorption equation compared to the Langmuir equation. This is evidenced by the error value of the Freundlich equation is smaller than the Langmuir equation by showing the value of R<sup>2</sup> which is close to number 1. The constant value of the Langmuir equation tingi bark for three times of dyeing obtained the b value is 0.2338 mg/gr and the k value is 0.00517 L/gr. For five of dyeing, the b value is 0.10817 mg/gr and the k value is 0.00421 L/gr. For the seven times of dyeing, the b value is 0.0670 mg/gr and the k value is 0.003899 L/gr. Whereas in the Freundlich equation for tingi bark for three times of dyeing, the n value is 0.4312 mg/g and the k value is 0.36374 x 10<sup>3</sup> L/gr. For five of dyeing, the n value is 0.30114 mg/g and the k value is 0.99586 x 10<sup>5</sup> L/g. For seven of dyeing, the n value is 0.2424 mg/g and the k value is 0.9354 x 10<sup>7</sup> L/g. The constant value of the Langmuir <em>Rhizopora stylosa</em> equation for three times of dyeing, the b value is 0.15635 mg / gr and the k value is 0.005224 L/gr. For five of dyeing, the b value is 0.08141 mg/gr and the k value is 0.004415 L/gr. For the seven of dyeing, the b value is 0.04909 mg/gr and the k value is 0.00408 L/gr. Whereas in the Freundlich equation for <em>Rhizopora stylosa</em> for three times of dyeing, the n value is 0.3862 mg/g and the k value is 0.1090 x 10<sup>4</sup> L/g. For five of dyeing, the n value is 0.2733 mg/g and the k value is 0.4355 x 10<sup>6</sup> L/g. For seven of dyeing, the n value is 0.2126 mg/g and the k value is 0.1545 x 10<sup>9</sup> L/g. It can be concluded that the more dyeing, the less the absorbency of the cloth on tannins. The color change of fixation the cloth in the dyeing of <em>Rhizopora stylosa</em> extract with tunjung is from brown to grayish brown, while with alum from brown to dark brown. The color change of fixation the cloth in the dyeing of tingi bark extract with alum is from brown to black, while with alum from brown to dark brown.</p>@font-face {font-family:"Cambria Math"; panose-1:2 4 5 3 5 4 6 3 2 4; mso-font-charset:0; mso-generic-font-family:roman; mso-font-pitch:variable; mso-font-signature:-536869121 1107305727 33554432 0 415 0;}@font-face {font-family:Garamond; panose-1:2 2 4 4 3 3 1 1 8 3; mso-font-charset:0; mso-generic-font-family:roman; mso-font-pitch:variable; mso-font-signature:647 2 0 0 159 0;}p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-unhide:no; mso-style-qformat:yes; mso-style-parent:""; margin-top:0cm; margin-right:0cm; margin-bottom:0cm; margin-left:.5pt; text-align:justify; text-justify:inter-ideograph; text-indent:-.5pt; line-height:103%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Garamond",serif; mso-fareast-font-family:Garamond; mso-bidi-font-family:Garamond; color:black; mso-ansi-language:EN-US; mso-fareast-language:EN-US;}.MsoChpDefault {mso-style-type:export-only; mso-default-props:yes; font-size:11.0pt; mso-ansi-font-size:11.0pt; mso-bidi-font-size:11.0pt; font-family:"Calibri",sans-serif; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:DengXian; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi; mso-ansi-language:EN-US; mso-fareast-language:EN-US;}.MsoPapDefault {mso-style-type:export-only; margin-bottom:8.0pt; line-height:107%;}div.WordSection1 {page:WordSection1;}

The use of Phanerochaete chrysosporium for modification of bentonite for preconcentration and determination of heavy metals

In this study, a solid phase extraction method was successfully applied in the preconcentration and determination of trace levels of Cu(II) and Cd(II) ions and Phanerochaete chrysosporium (white rot fungus) modified bentonite was used as adsorbent. After the biosorption of Cu(II) and Cd(II) ions, metal concentrations in the samples were determined by atomic absorption spectrophotometry. pH, adsorbent amount, eluent type, sample volume, and flow rate, which are effective in the adsorption of metal ions, have been studied. 1 M HCl was used for desorption of these metal ions retained (recovery 95–100%). In addition, the effect of interfered ions has also been investigated. Sorption data were examined according to Langmuir and Freundlich adsorption equations. The results obtained show that the applied method has a high metal biosorption capacity, and Cu(II) and Cd(II) ions are successfully recovered. It was also successful in applying the proposed enrichment method to real water samples.Recovery values between 92.3% and 97.3% were obtained for the studied metal ions. According to the results, the proposed method can be successfully applied to water analysis at 95% confidence interval.

The Use of an Organo-Kaolinite Sorbent in a Permeable Reactive Barrier for Remediating Groundwater Contaminated with Methylene Blue Dye: Experimental and Theoretical Investigation

The removal of aqueous methylene blue (MB) dye using organically modified natural Na-kaolinite was optimized. Organo-kaolinite was synthesized by replacing exchangeable Na+ ions in Na-kaolinite with cetyltrimethylammonium bromide (CTAB), and the adsorption behaviour was systematically explored as an efficient adsorbent for the removal of dyes. Furthermore, the properties of the obtained samples were characterized by FTIR spectrophotometric analysis, which confirmed that CTAB cations had modified the kaolinite to possess a new functional group. Batch mode experiments were conducted to test the performance of the modified kaolinite in removing MB dye to optimize the following experimental conditions: adsorbent quantity, initial concentration, mixing speed, contact time and initial pH. The findings indicated that the MB adsorbent efficiency could reach up to 100% when the above conditions were set at 0.3 g/100 mL, 50 mg/L, 200 rpm, 60 min and pH = 12, respectively. The adsorption isotherms and kinetics of the organic-modified kaolinite for MB concurred with Freundlich adsorption equation and the pseudo-second-order kinetics, respectively. In accordance with the principles of environmental preservation and reuse of waste, granulated glass waste was used to optimize the adsorption efficiency of kaolinite. Furthermore, two tested reactive systems were used in two-dimensional (2D) domain experiments by mixing a 1:1 ratio of modified kaolinite:granulated glass waste. The COMSOL Multiphysics 3.5a software was utilized to determine the spread of MB within the permeable reactive barrier (PRB) for the 2D domain at equilibrium conditions. • Kaolinite was modified by cetyltrimethylammonium bromide to remove methylene blue. • Organo-kaolinite was used in a two-dimensional permeable reactive barrier. • The COMSOL Multiphysics model was used to simulate the permeable reactive barrier.

First protein affinity application of Cu2+-bound pure inorganic nanoflowers

Today, a new kind of materials is introduced to separation media day by day to increase the efficiency of the separation processes, and multiple-petalled nanostructured materials are one of them. In this study, new pure inorganic copper phosphate nanoflowers (pCP-NFs) were synthesized, and some environmental conditions affecting on binding mechanism with human serum albumin were evaluated via changing medium pH, temperature, initial human serum albumin (HSA) amount and salt concentrations. Before experimental studies, pCP-NFs were subjected to some characterization tests such as scanning electron microscopy, energy-dispersive X-ray, X-ray diffraction and Fourier transform infrared spectroscopy. Besides a lot of valuable instrumental data, some obtained experimental ones as follows: after Cu2+ ions attachment to pCP-NFs as ligand, maximum HSA adsorption capacity of obtained Cu2+-pCP-NFs was found as 225.7 mg/g with an initial concentration of 1.5 mg/mL at pH 7 and 25 °C. Langmuir and Freundlich adsorption equations were evaluated for determination of appropriate adsorption model in interaction, and Langmuir model found as the fittest one with a R2 of 0.9949 was also reviewed to determine Gibbs free energy between HSA and Cu2+-pCP-NFs interaction.

Efficiency of natural clay and titania P25 composites in the decolouring of methylene blue (MB) from aqueous solutions: dual adsorption and photocatalytic processes

In this paper, we use Tunisian clay materials as alternative low-cost adsorbents, as well as substrates to immobilise TiO2 for the decolouration of methylene blue (MB) dye solutions. The collected raw clay from the mine of Tamra was characterised by various techniques, such as X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray fluorescence (XRF). XRD patterns of the raw clay showed halloysite as the main phase (61%), with a lower content of kaolinite (39%). For MB adsorption, the experimental data were fitted by Langmuir and Freundlich adsorption equations. It was found that the studied clays alone were not very efficient at adsorbing MB dye molecules. The decolouration of MB was improved by adding a photocatalytic function to the clay, by adding various amounts of TiO2 nanopowder (20–80 wt%) to the clay, imbuing it with photocatalytic capabilities. These combined effects of the phenomena of adsorption and photocatalysis for MB removal by the TiO2-doped clay resulted in a very satisfactory performance, even with the relatively low quantity of 20 wt% added TiO2 photocatalyst. This gave 48.6% removal after only 30-min adsorption in the dark, increasing to 84.1% removal after a further 3 h under UV light, through combined chemo-physical adsorption and photocatalytic decolouration phenomena.