Determination of rice husk activated Carbon capacity in adsorption of Cu Metal from Sasirangan liquid waste based on isotherm model

The process of manufacturing Sasirangan - a traditional fabric of South Kalimantan - has an impact that affects environmental pollution, namely the dyeing process of the fabric. The synthetic dyes used contain heavy metals and one of those toxic metals is copper (Cu). This study aims to determine the adsorption capacity of rice husk activated carbon adsorbent by adjusting the adsorption pattern based on isotherm models as the treatment to sasirangan liquid waste. The method consists of three stages: preparation of adsorbent by carbonization process, chemical and physical activation, then continued by adsorption process of Cu metal with carbon from rice husks with variations of adsorbent dose (2, 4, and 6 grams). This treatment was conducted by batch process. In this reseach, the adsorption capacity of rice husk adsorbent towards heavy metal Cu in sasirangan liquid waste was determined from the equilibrium state with the Langmuir isotherm equation and Freundlich isotherm equation. Based on isothermal studies of adsorption data, the correlation coefficient values obtained from the isotherm model approaches are: for dose of 2 grams adsorbent, Langmuir R2 = 0.9991 and Freundlich R2 = 0.9981; for dose of 4 grams adsorbent, Langmuir R2 = 0.9992 and Freundlich R2 = 0.9989; for dose of 6 grams adsorbent, Langmuir R2 = 0.9990 and Freundlich R2 = 0.9986. The results of investigation indicate that adsorption data correlated well with Langmuir isotherm model.

Kinetic Study of Adsorption Active Carbon Cassava Skin for Removal of Acetic Acid from Aqueous Solution

The amount of liquid wastes containing acetic acid found from food industry such as tofu home industry released is relatively high and pollutes water quality and also environment nearby. Several methods reducing pollutant in liquid wastes are available, one of which is adsorption using carbon as an adsorbent. The production of cassava in Indonesia was about 23.936 tons in year 2013 which produced cassava’s skin wastes about 2.393 tons. Mostly these cassava’s skin wastes containing around 59.31% carbon is disposed as garbage. This research is to develop more on reducing acetic acid containing in liquid waste by carbon active from cassava’s skin with variation of particle sizes, reaction times and acetic acid liquid waste concentrations, and also to study the kinetic reaction of cassava skin active carbon adsorbing acetic acid between Freundlich and Langmuir isotherm equations. The result shows the kinetic adsorption follows Freundlich isotherm equation with maximum capacity of Cassava skin active carbon 0.7 mg/g at particle size of adsorbent of 0.3375 mm and reaction time of 105 minutes.

Solketal Removal from Aqueous Solutions Using Activated Carbon and a Metal–Organic Framework as Adsorbents

The worldwide rise in biodiesel production has generated an excess of glycerol, a byproduct of the process. One of the most interesting alternative uses of glycerol is the production of solketal, a bioadditive that can improve the properties of both diesel and gasoline fuels. Even with its promising future, not much research has been performed on its toxicity in aqueous environments. In this work, solketal adsorption has been tested with two different commercial adsorbents: an activated carbon (Hydrodarco 3000) and a metal–organic framework (MIL-53). Diclofenac and caffeine were also chosen as emerging contaminants for comparison purposes. The effect of various parameters, such as the adsorbent mass or initial concentration of pollutants, has been studied. Adsorption kinetics with a better fit to a pseudo-second-order model, intraparticle diffusion, and effective diffusion coefficient were studied as well. Various isotherm equation models were employed to study the equilibrium process. The results obtained indicate that activated carbon is more effective in removing solketal from aqueous solutions than the metal–organic framework.

Chemical, electrochemical and surface studies of new metal–organic frameworks (MOF) as corrosion inhibitors for carbon steel in sulfuric acid environment

The effects of [Co2 (SCN) 4(hmt)2(H2O)6. H2O] (SC1) and [Co (CN)6 (Me3Sn)3(H2O). (qox)] (SCP2) MOF as corrosion inhibitors on C-steel in 0.5 M sulfuric acid solutions are illustrated utilizing mass reduction (MR), electrochemical [potentiodynamic polarization (PP), and AC electrochemical impedance (EIS)]. The experiments revealed that as the dose of these compounds rose, the inhibition efficacy (IE percent) of C-steel corrosion improved, reaching 80.7–93.1% at dose 25 × 10−6 M for SC1 and SCP2, respectively. IE percent, on the other hand, dropped as the temperature range grew. SC1was adsorbed physically and chemically (mixed adsorption) but SCP2 was adsorbed physically on the surface of C-steel and conformed to the Langmuir adsorption isotherm equation. The PP studies revealed that these compounds act as mixed kind inhibitors. To establish the morphology of the inhibited C-steel surface, scanning electron microscopy (SEM), energy transmitted X-ray (EDX), and atomic force microscopy (AFM) studies were used. All tested experiments were in good agreement.

Boron Removal by Sorption on Modified Chitosan Hydrogel Beads

An excess concentration of boron in irrigation and drinking water can negatively affect the yield of plants and the human nervous system, respectively. To meet the recommended levels, hybrid biosorbent hydrogel beads based on chitosan and manganese (II-IV) were employed for the removal of boron from aqueous media. The results showed that the biosorbent effectively removed boric acid from the aqueous medium at neutral pH over a sorption time of 2 h and the liquid/hydrogel ratio of 20 mL/g, achieving a maximum sorption capacity near 190 mg/g. The modeling of the sorption equilibrium data indicated that the Freundlich isotherm equation gave the best fit out of the isotherm models examined. A pseudo-second-order model was found to best describe the sorption kinetics. The favorable attachment of manganese to the chitosan structure enabled the sorption of boron and was confirmed by FTIR, RS, XRD, SEM and ICP-OES methods. Boron desorption from the spent biosorbent was successfully achieved in three cycles using a NaOH solution. In general, the results of this research indicate that this method is one of the possibilities for improving water quality and may contribute to reducing pollution of the aquatic environment.

Optimizing modified rice bran for treating aqueous solutions polluted by Cr (VI) ions: isotherm and kinetics analyses

This study investigated the possibility and efficiency of absorbing chromium (VI) (Cr [VI]) ions from the polluted solutions by employing the chemically modified adsorbents (alkali, biochar, and acid rice bran), focusing on the possible impacts of the solution’s pH values, adsorbent’s dosages, concentrations, and contact times. The colori-metric method was used for Cr determination by employing an ultraviolet/visible spectrophotometer. The scanning electron microscope and Fourier transform infrared spectroscopy were used to analyze the characteristics of the modified adsorbents. The findings indicated that the optimized acid, biochar, alkali, and unmodified rice bran removal efficiency for Cr (VI) were 94.50%, 94.27%, 88.60%, and 90.18%, respectively. The increase of adsorbent dosage up to 2 g/L led to a rise in removal effectiveness (82.06%). Furthermore, the highest removal efficiency was obtained (94%) at the pH of 2.0, the contact duration of 100 min, Cr (VI) concentration of 50 mg/L, and dosage of 2 g/L, which was statistically the optimal condition for the modified rice bran. The adsorption kinetics was agreeably suited to pseudo-second-order, whereas the Freundlich isotherm equation was also suitably expounded the study’s findings. The findings implied that the acid and biochar rice bran performed remarkably in the reme-diation of the wastewater compared with alkali rice bran for reuse for industrial, agricultural, and environmental purposes.

Chemical, Electrochemical And Surface Studies of New Metal-Organic Frameworks (MOF) As Corrosion Inhibitors For Carbon Steel In Sulfuric Acid Environment

The effects of [Co2(SCN)4(hmt)2(H2O)6. H2O] (SC1) and [Co (CN)6(Me3Sn)3(H2O). (qox)] (SCP2) MOF as corrosion inhibitors on C-steel in 0.5 M sulfuric acid solutions are illustrated utilizing mass reduction (MR), electrochemical [potentiodynamic polarization (PP), and AC electrochemical impedance (EIS)]. The experiments revealed that as the dose of these compounds rose, the inhibition efficacy (IE percent) of C-steel corrosion improved, reaching 80.7- 93.1 percent at dose 25x10-6 M for SC1 and SCP2, respectively. IE percent, on the other hand, dropped as the temperature range grew. Both SC1 and SCP2 were adsorbed physically on the surface of C-steel and conformed to the Langmuir adsorption isotherm equation. The PP studies revealed that these compounds act as mixed kind inhibitors. To establish the morphology of the inhibited C-steel surface, scanning electron microscopy (SEM), energy transmitted X-ray (EDX), and atomic force microscopy (AFM) studies were used. All tested experiments were in good agreement.

PEMBUATAN BIOADSORBEN DARI SABUT KELAPA DAN TEMPURUNG KELAPA UNTUK MENURUNKAN KADAR BESI (Fe)

Salah satu kandungan bahan pencemar logam berat dalam air adalah besi. Besi (Fe) merupakan senyawa logam berat yang dapat membahayakan kesehatan manusia seperti keracunan (muntah), kerusakan usus, penuaan dini hingga kematian mendadak, radang sendi, cacat lahir, gusi berdarah, kanker, sirosis ginjal, sembelit, diabetes, diare, pusing, mudah lelah, hepatitis, hipertensi dan insomnia. Pengolahan yang dapat dilakukan untuk menghilangkan kandungan logam berat besi dalam air yaitu pengolahan dengan adsorpsi menggunakan bioadsorben dari limbah pertanian. Limbah pertanian yang digunakan dalam penelitian ini yaitu tempurung kelapa dan sabut kelapa. Penelitian ini bertujuan agar dapat mengetahui efisiensi maupun kapasitas adsorpsi bioadsorben terhadap limbah besi (Fe) menggunakan sistem batch serta dapat mengetahui model isoterm yang sesuai pada adsorpsi ini. Metode dari penelitian ini menggunakan penelitian eksperimen dengan variasi massa 3,75 gr tempurung kelapa : 1,25 gr sabut kelapa, 2,5 gr tempurung kelapa : 2,5 gr sabut kelapa, 1,25 gr tempurung kelapa : 3,75 gr sabut kelapa, 5 gr tempurung kelapa dan 5 gr sabut kelapa dengan waktu kontak selama 15,30 dan 45 menit. Hasil dari penelitian ini menunjukkan persentase efisiensi dan kapasitas adsorpsi tertinggi menggunakan bioadsorben 1,25 gr tempurung kelapa : 3,75 gr sabut kelapa dengan waktu pengadukan selama 45 menit sebesar 92% dan 0,628 mg/g. Dari hasil persamaan isoterm, nilai regresi (R2) yang diperoleh paling besar sebesar 0,9921 pada isoterm Langmuir. Dari penelitian ini, dapat disimpulkan bahwa model isoterm yang cocok untuk adsorpsi menggunakan bioadsorben tempurung kelapa dan sabut kelapa yaitu isoterm Langmuir. Kata kunci: adsorpsi, besi (Fe), bioadsorben, isoterm adsorpsi, sabut kelapa, tempurung kelapa. One of the heavy metal pollutants in water is iron. Iron (Fe) is a heavy metal compound that can endanger human health such as poisoning (vomiting), intestinal damage, premature aging until sudden death, arthritis, birth defects, bleeding gums, cancer, kidney cirrhosis, constipation, diabetes, diarrhea, dizziness, easily tired, hepatitis, hypertension and insomnia. Treatment that can be done to remove the heavy metal content of iron in water is processing by adsorption using bioadsorbents from agricultural waste. Agricultural wastes used in this research are coconut shell and coconut fiber. This study aims to determine the efficiency and capacity of bioadsorbent adsorption of iron (Fe) waste using a batch system and to find out the appropriate isotherm model in this adsorption. The method of this study uses experimental research with a mass variation of 3.75 grams of coconut shell: 1.25 grams of coconut husk, 2.5 grams of coconut shell: 2.5 grams of coconut husk, 1.25 grams of coconut shell: 3.75 grams of coir coconut, 5 gram coconut shell and 5 gram coconut fiber with contact time for 15.30 and 45 minutes. The results of this study showed the highest percentage of efficiency and adsorption capacity using bioadsorbent 1.25 grams of coconut shell: 3.75 grams of coconut husk with stirring time for 45 minutes by 92% and 0.628 mg / g. From the results of the isotherm equation, the regression value (R2) obtained is greatest at 0.9921 on the Langmuir isotherm. From this study, it can be concluded that the isotherm model that is suitable for adsorption using coconut shell and coconut husk bioadsorbent is Langmuir isotherm. Keywords: Adsorption, bioadsorbent, coconut fiber, coconut shell, iron (Fe), isoterm adsorption.

Effectivity of Indonesian Rice Husk as an Adsorbent for Removing Congo Red from Aqueous Solutions

Indonesian rice husk biochar (RH-BC) was prepared by pyrolysis method at 500°C and characterized using X-ray diffraction, Fourier-transform infrared spectroscopy, surface-area-specific analysis by Brunauer-Emmett-Teller, and scanning electron microscopy. The RH-BC were used as adsorbents for enhancing the adsorption of Congo red compared to pristine rice husk (RH) in aqueous solutions. The results of characterization through surface-area-specific analysis showed the surface area of RH-BC (72.25 m2/g) was ten times higher than RH (7.08 m2/g) owing to high-temperature treatment. The results of the adsorption study showed that the RH and RH-BC followed the pseudo-second-order kinetic model and the Freundlich isotherm equation with maximum adsorption capacities of 85.470 mg/g and 72.993 mg/g for the RH-BC and RH, respectively. The thermodynamic parameters of adsorption indicated spontaneous and endothermic processes. The reusability of the adsorbents (RH and RH-BC) showed that they are potentially suitable for extracting Congo red from aqueous solution up to three adsorption-desorption cycles. Their performance sharply decreases after the fourth and fifth cycles.