Activated Carbon Adsorption Research Articles

Enabling in situ electro-regeneration systems for PFOA-laden spent activated carbon adsorbents reuse

Adsorption is the main commercially used water treatment technology to remove per-and polyfluoroalkyl substances (PFAS) from water. Despite the high performance of this physical separation treatment, the endpoint of this technology is the production of PFAS-laden spent activated carbon. So far, several regeneration techniques have been used for spent activated carbon. However, activated carbon regeneration techniques remain challenging due to a limited understanding of cost/benefit analysis. In the present study, we developed the first proof of concept in situ electro-regeneration technique for the regeneration of perfluorooctanoic acid (PFOA, as a model long chain PFAS compound) laden-F400 using electro-assisted up-flow rapid small-scale column test (RSSCT) setup. The laboratory column experiments were conducted exploring sequential adsorption and electro-regeneration cycles. The results showed that the electro-regeneration of saturated F400 reinstated up to ∼60% of initial capacity. After the 1st regeneration cycle, the regeneration efficiency of spent F400 remained similar following 4 consecutive adsorption/regeneration cycles. The calculated operational cost for electro-regeneration was 0.70 kWh/kg, which is more competitive than current regeneration techniques. Overall, this novel proof-of-concept approach can be used as a promising alternative regeneration technique to existing ones to minimize waste PFAS-laden adsorbents in landfills and decrease the amount of CO2 emissions associated with the incineration of these sorbents.

Research on the adsorption rule of porous media on supersaturated total dissolved gas

AbstractDischarge of high dams may result in supersaturated total dissolved gas (TDG) in water, which could cause fish that live downstream river to suffer from gas bubble disease. If supersaturated TDG water was taken as a water source for breeding and proliferation stations, farmed fish was confined and may face more severe problems than fish living in the river. Therefore, it is critical to develop strategies to reduce the negative effects of supersaturated TDG. In this research, the adsorption effect of porous media on supersaturated TDG was explored, including biofilter adsorption experiments and previously existing activated carbon adsorption experiments. The experimental results showed that adding porous media to the water effectively accelerated the dissipation of supersaturated TDG, and the adsorption effect was associated with the specific surface area, mass density, and initial TDG saturation. To quantitively evaluate the adsorption effects of the porous media, the porous adsorption coefficient was proposed to express the adsorption rate of porous media on supersaturated TDG. The porous adsorption coefficient was related to the initial TDG saturation and the specific surface area of the porous media. The porous adsorption coefficient increased with increasing the specific surface area and decreasing initial TDG saturation. Based on this, an equation related to the specific surface area, initial TDG saturation, and the porous adsorption coefficient was developed. This equation may be used to evaluate the adsorption effect of porous media on supersaturated TDG. This study could serve as a crucial resource in reducing the adverse impacts of supersaturated TDG.

Removal of aflatoxins in peanut oils by activated carbon functionalized with sodium dodecyl sulfonate

In this study, three kinds of novel modified activated carbon adsorbent were prepared by different concentrations of sodium dodecyl sulfonate solution, and carried out by FTIR, XRD, TGA, SEM, and N2-adsorption-desorption analytical techniques. The adsorption mechanism of aflatoxins on three types of modified activated carbon had been systematically investigated by isotherm, kinetic, and thermodynamic studies. The optimized adsorption conditions (amount, temperature, time) were determined by combining different types of aflatoxins (AFB1, AFB2, AFG1 and AFG2) removal efficiency in peanut oil. Notably, the modification of activated carbon using a 2-fold critical micelle concentration sodium dodecyl sulfonate solution not only remove 93.5% of AFB1 from peanut oils containing four aflatoxins (58.89 μg/kg), but also remain nearly unchanged in the phytosterol content in oils. In conclusion, the modified activated carbon with low cost and high efficiency showed a great potential for application in the adsorption of four aflatoxins from contaminated edible oils.

Synthesis, characterization and adsorption studies on activated carbon adsorbent synthesized from Kigelia africana for removal of acid blue 113 dye from synthetic solution

The need for waste water treatment, which can be accomplished via adsorbents, is growing today. Adsorbents are inexpensive, environmentally responsible, and made of biodegradable materials that can be replenished. In this work, chemical activation is used to create powdered activated carbon from Kigelia africana. The raw material was chosen because this fruit has not been the subject of any significant research on dye removal. It is also a poisonous fruit, abundantly available in nature, has high cellulose content, carbon rich and possesses less ash content thus making it a low cost activated carbon. After activation, the surface area has increased from 5 m2/g to 400 m2/g, morphology studies with SEM analysis and also analyzed the functional groups with FT-IR. These properties have made our adsorbent highly efficient for dye removal. The batch adsorption studies have been carried out for the removal of acid blue 113 using various combinations of synthetic dye solution concentrations (50–300 mg/L), adsorbent dosage 0.4–7 g/L), contact time (30–300 min), and pH (2–10). The removal % efficiency and capacity (mg/g) are obtained from this work as 99.79 % and 188.89 mg/g, respectively.

Quantitative simulationSimulation of nitrogen doping effects on benzene selective adsorption by activated carbon in aqueous conditions

Investigating the impact of nitrogen doping on the selective adsorption of benzene on activated carbon under aqueous conditions holds significant importance in regulating nitrogen content on activated carbon precisely and enhancing benzene adsorption in the air. This study utilizes quantum chemical simulation to systematically compute the pairwise interactions of pyridine nitrogen, pyrrole nitrogen, graphite nitrogen, and their coexistence on carbon materials, including electrostatic potential, van der Waals potential, and polarity changes. We examine the adsorption of benzene and water on nitrogen-doped carbon materials and calculate the type and proportion of weak interactions in the adsorption process through energy decomposition analysis. Visual analysis of weak interactions is conducted via independent gradient scatter plots and isosurface plots. Based on this research, we investigate the influence of nitrogen doping on the competitive adsorption of benzene and water on carbon materials using adsorption energy and configuration changes. Our findings reveal that nitrogen doping disrupts the uniform electrostatic potential distribution and polarity of carbon materials. Specifically, graphite nitrogen inhibits water molecule adsorption by enhancing mutual repulsion and weakening dispersion and electrostatic interactions, consequently promoting benzene adsorption on carbon materials. Moreover, hydrogen bonds form between pyridine nitrogen, pyrrole nitrogen, and water, making carbon materials more hydrophilic. However, when combined with graphite nitrogen, this increases the negative van der Waals potential of carbon materials, further enhancing benzene adsorption. Experimental results align with the simulation, reinforcing the significance of this research in developing efficient activated carbon adsorbents for benzene under aqueous conditions.

Pharmaceutically active compounds in aqueous environment: recent developments in their fate, occurrence and elimination for efficient water purification.

The existence of pharmaceutically active compounds (PhACs) in the water is a major concern for environmentalists due to their deleterious effects on living organisms even at minuscule concentrations. This review focuses on PhACs such as analgesics and anti-inflammatory compounds, which are massively excreted in urine and account for the majority of pharmaceutical pollution. Furthermore, other PhACs such as anti-epileptics, beta-blockers and antibiotics are discussed because they also contribute significantly to pharmaceutical pollution in the aquatic environment. This review is divided into two parts. In the first part, different classes of PhACs and their fate in the wastewater environment are presented. In the second part, recent advances in the removal of PhACs by conventional wastewater treatment plants, including membrane bioreactors (MBRs), activated carbon adsorption and bench-scale studies concerning a broad range of advanced oxidation processes (AOPs) that render practical and appropriate strategies for the complete mineralization and degradation of pharmaceutical drugs, are reviewed. This review indicates that drugs like diclofenac, naproxen, paracetamol and aspirin are removed efficiently by conventional systems. Activated carbon adsorption is suitable for the removal of diclofenac and carbamazepine, whereas AOPs are leading water treatment strategies for the effective removal of reviewed PhACs.

Reduction of Heavy Metal (Pb) ions in industrial waste using activated carbon based on used catalysts

Used catalyst-based activated carbon is activated carbon made from used catalysts from the crude oil cracking process. The used catalyst used is a type of crystalline Zeolite with a regular structure, which contains elements of Silica Oxide, Alumina Oxide, and Calcium Oxide. The use of organic activated carbon to treat waste has been widely used, the use of used catalyst waste as activated carbon is very potential because the catalyst used for oil company cracking is no longer used. Tofu industry is one of Indonesia's industries dominated by small-scale businesses with limited capital, so most tofu industries do not have waste treatment units, where liquid waste is directly discharged into sewers or water bodies without treatment first. Tofu industrial waste contains pollutants both organic and inorganic. Initial analysis of tofu industry liquid waste containing Pb metal. This study aims to determine the effect of mass variation and stirring time of used catalyst-based activated carbon adsorbent on reducing Heavy Metal Ions (Pb) in tofu industry liquid waste. The adsorption process is carried out with mass variations of activated carbon of 5, 10, 15, 20, and 25 grams. Stirring time variations are 30, 60, 90, 120, and 150 minutes. From the results of the study, it is known that the best condition for reducing Pb content was obtained at a stirring time of 60 minutes and a large catalyst-based activated carbon mass of 66.33%

Preparation of an Activated Carbon Composite with High Thermal Conductivity Based on Emulsified Asphalt and Carbon Nanotubes and its Adsorption Performance for n‐Hexane

AbstractActivated carbon, as the main adsorption material for treating VOCs, has been widely used. To solve the problem of safety hazards in activated carbon adsorption process due to the large amount of heat released, highly thermally conductive composite activated carbon (A‐AC/CNTs) was prepared using asphalt and highly thermally conductive carbon nanotubes (CNTs) for thermal conductivity improvement. Uniform dispersion and firm loading of CNTs in the carbon production material were achieved by dispersing carbon nanotubes (CNTs) in the asphalt‐in‐water emulsion. Experimental results showed that the specific surface area of A‐AC/CNTs reached a maximum when the loading of CNTs was 0.5 wt %. Meanwhile, the thermal conductivity increased by 1.5 times compared with the original activated carbon. The adsorption capacity of n‐hexane reached the maximum of 2868 mmol ⋅ g−1, and the adsorption capacity increased by 21.41 %. It also maintained good regeneration performance after dynamic adsorption experiments.

Scavenging Efficiency of Activated Charcoal of Sweet Corn Cop and Areca Nut Shell for Carcinogenic Salicylic Acid and Methylene Blue

Activated plant charcoal plays major role in adsorption chemistry and finds a huge application in industry, pharmaceuticals, cosmetics and water treatment. Present work planned to utilize waste sweet corn cop and areca nut husk to prepare charcoal by chemical method. The charcoal was carbonized at 8000C using muffle furnace. The adsorption efficiency of the experimental activated carbon adsorbents towards the model organic compounds methylene blue and salicylic acid were assessed by UV-Vis spectrophotometric method. Experimental results clearly indicates that sweet corn cop charcoal recorded maximum absorption for salicylic acid 640ppm/g in compare to areca nut shell husk charcoal 480ppm/g. Sweet corn cop charcoal recorded optimum absorption for methylene blue 240 ppm/g in compare to areca nut shell husk charcoal 240ppm/g. The experimental charcoal projects noticeable results in scavenging salicylic acid and methylene blue from polluted samples. This experimental results and affordable cost the raw material made the sweet corn cop and areca nut husk activated carbon a powerful alternative for the adsorption of carcinogenic organic compounds salicylic acid and methylene blue.

Challenges in the microwave heating of structured carbon adsorbents

Microwave heating is a promising method for achieving energy-efficient electrification of temperature swing adsorption processes. However, to successfully design the adsorbent bed and the regeneration step, it is crucial to analyse the limited penetration depth of microwaves. In this study, we present the first comprehensive investigation of microwave heating applied to large structured activated carbon adsorbents. The experiments were conducted inside a monomode microwave applicator, which consists of a rectangular waveguide operated at a frequency of 915 MHz. monolithic adsorbents of various shapes and sizes (cubic, rectangular cuboid, cylindrical) with dimensions up to 10 cm, were placed inside the cavity and subjected to microwave powers ranging from 10 to 200 W. To maximise microwave absorption by the sample, the geometry and impedance of the cavity were modified. Temperature measurements were taken at different positions within the monoliths to investigate heating homogeneity. The combined influence of reflections and the limited penetration depth results in very different temperature profiles as the size and shape of the monolith vary, even after optimising the cavity. In general, thinner monoliths heat better at the centre, whereas thicker monoliths experience better heating at the point closer to the radiation source. Additionally, these materials were characterized in terms of their dielectric and textural properties and composition, and it was determined that variations in these properties result in significant differences in the heating behavior. The choice of adsorbent bed size and heating time can be adjusted accordingly to maximise energy efficiency and heating homogeneity. Furthermore, the rotation of monoliths within the monomode electromagnetic field to achieve heating homogeneity is examined and a comparison with a multimode device is established.

Unveiling the molecular responses of dissolved organic matter in landfill leachate to activated carbon adsorption

Powdered activated carbon (PAC) is an effective method for removing dissolved organic matter (DOM) in membrane bioreactor effluent of landfill leachate (MBR effluent). Among commercially available PACs, wood-based PAC (WoAC) and coal-based PAC (CoAC) are two most common ones. However, the interactions between two PACs and DOM in MBR effluent at the molecular level as well as the effect of PACs properties on the adsorption of DOM compounds are not fully understood. To address the gap, Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), three-dimensional fluorescence excitation-emission matrix (EEM) spectroscopy and other spectroscopic techniques were employed to study the change of DOM in MBR effluent when adsorbed by WoAC and CoAC. The results showed that CoAC had a better removal performance of DOM (89.2% for UV254 and 78.4% for DOC) than WoAC (80.9% for UV254 and 70.8% for DOC), which was likely due to the Fe component in CoAC playing an important role in the DOM adsorption process. Both WoAC and CoAC exhibited preferential adsorption for compounds with high unsaturation or poor oxygen. Moreover, the Fe component in CoAC may bind with some functional groups (e.g., carboxyl groups) in unsaturated compounds, which may enhance the adsorption of unsaturated compounds. These findings deepen our understanding of PAC-DOM interactions at the molecular level and provide guidance for designing cost-effective PACs for landfill leachate treatment.

Effect of granular activated carbon adsorption on mitigating microfiltration membrane fouling by algal organic matter

Abstract Algal blooms can seriously affect the operation of water treatment processes including low-pressure (micro- and ultrafiltration) and high-pressure (nanofiltration and reverse osmosis) membranes mainly due to the accumulation of algae-derived organic matter (AOM). This study investigated the effect of granular activated carbon (GAC) pretreatment on PVDF microfiltration performance for the removal of AOM. Dissolved organic matter (DOM) solution of commercial humic acid, extra- and intracellular organic matter from two species of algae, and Cyanobacteria were used for the investigation of the fouling potential of the membrane. A comparison study of different DOM removal and fouling behaviors of microfiltration (MF) after GAC adsorption as pretreatment was evaluated under variable GAC dosage and solution pH. Almost 15–20% improvement in flux and decline in irreversible fouling occurred due to the pretreatment using 1.0 g/L of GAC for an hour. The intracellular material caused higher membrane fouling than humic acid due to the hydrophilic nature of the AOM. Membrane fouling and decline in flux increased with increasing pH in the range of 5.0–8.0. The comparison results might help to provide insights into the real challenge of dealing with the treatment of algal-laden water.

Influence of furnace atmospheres and potassium hydroxide activation on the properties of bamboo activated carbon and its adsorption towards 4-nitrophenol

Bamboo activated carbon (BAC) was synthesized as adsorbent for 4-NP adsorption due to its incredible adsorptive capability that has led it to its popularity. The effect of furnace atmospheres (argon, limited-air, vacuum), carbonizing temperatures (400–600 ℃), and activating temperatures (500–700 ℃) were investigated to achieve the largest surface area (SBET) of BAC. Its properties were analysed by using BET, FTIR, LVSEM, XRD, TGA, and Elemental analysis. The 4-NP adsorption was conducted by varying the pH (3−11), BAC dosages (0.05–0.4 g L-1), and 4-NP initial concentrations (10–100 mg L-1). Consequently, the argon-treated BAC (A67) had the highest SBET (1795.38 m2 g-1), stating that 600 ℃ of carbonizing temperature with 700 ℃ of argon flow activating temperature is the best condition to synthesize the BAC. The best adsorption efficiency (95.12%) was achieved by using A67 (pH 5, 0.2 g L-1, 50 mg L-1) with its maximum adsorption capacity (411.95 mg g-1). The Redlich-Peterson was the best-fitted isotherm model whereas the Pseudo-Second-Order (PSO) and Elovich were the best-fitted kinetic models for the 4-NP adsorption on BAC. The adsorption mechanism was analysed by applying the IPD model to the experimental data and was depicted in an insightful illustration. Overall, this research provides valuable insights into the adsorbent synthesis processes and highlights the importance of furnace atmospheres and KOH activation in tailoring the properties and adsorption activity of bamboo activated carbon adsorbents. The findings contribute to the development of sustainable and efficient adsorbent materials derived from renewable resources, with significant implications for environmental remediation and waste treatment applications.

Novel Method for the Arsenic Removal Experiment and Mechanism Analysis.

This study focuses on the hydrothermal synthesis of magnetically activated carbon and its efficacy in As(III) adsorption. The successful incorporation of magnetite nanoparticles within the porous carbon structure was confirmed, enriching the adsorbent's properties. Comprehensive characterization was performed to analyze the pore size distribution, zeta potential at varying pH levels, and thermostability using thermogravimetric analysis. These adsorbents exhibited high As(III) removal efficiency with a uniform pore distribution. The zeta potentials were observed to decrease with an increase in pH, suggesting a relationship between adsorbent charge and pH. Adsorption dynamics were rigorously modeled using pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion models for different adsorbents labeled as a,b,c, and d. Each adsorbent displayed unique fitted parameters, revealing varied adsorption capabilities. The study further explored the adsorption kinetics and found that the pseudo-second-order kinetics model and the Langmuir model were most appropriate for describing the adsorption process. Adsorption thermodynamics was also fitted to elucidate the underlying adsorption mechanisms. For the a,b,c, and d adsorbents, the pseudo-first-order model, the qe(cal) values for the four adsorbents were 434.2, 418.4, 283.5, and 279.5 μg/g, respectively. Take adsorbent a as an example; the qm values for 298, 303, 308, and 313 K were 702, 673, 605, and 589 μg/g, respectively, and KL values of these temperatures were 0.021, 0.031, 0.018, and 0.009 L/μg, respectively. For the Langmuir model, the R2 values at the four temperatures were 0.999, 0.978, 0.985, and 0.993, respectively, which indicated that the Langmuir model showed higher fitness. For the Freundlich model, the KL values (L/μg) at the parameters of these temperatures are 432, 409, 328, and 294, respectively. For the Freundlich model, the 1/n values at temperatures of 298, 303, 308, and 313 K are 0.049, 0.045, 0.052, and 0.035, respectively. For the Freundlich model, the R2 values at parameters of 298, 303, 308, and 313 K are 0.986, 0.989, 0.982, and 0.872, respectively. For the Temkin model, the B values (in J/mol) are 30.93, 0.894, 0.824, and 0.782 at these temperatures, respectively. The KT values (in L/μg) are 1.02 × 106, 0.07 × 106, 0.003 × 106, and 0.002 × 106, respectively. The R2 values are 0.973, 0.958, 0.972, and 0.894, respectively. In the end, the ΔH, ΔS, and ΔG values for different adsorbents were calculated. Collectively, these findings contribute significant insights into the design and application of magnetically activated carbon adsorbents for effective As(III) removal.

Optimization of removal of toluene from industrial wastewater using RSM Box–Behnken experimental design

The study is concerned with the adsorption of toluene from real wastewater using granular beads of activated carbon. The adsorbent was analyzed before and after the process using Scanning Electron Microscope analysis to characterize its surface characteristics. The adsorption parameters including solution pH, contact time, dosage of adsorbent, temperature and toluene initial concentration were optimized using response surface methodology (RSM) Box-Behnken experimental design to maximize the toluene adsorption. The adsorption capacity of the adsorbent was 298 mg g−1 and the maximum toluene removal was 99.5% which was achieved in the following optimal conditions: pH: 2, 100 min, adsorbent dosage: 0.7 g L−1, 40 °C and initial concentration: 30 mg L−1. The adjusted coefficient of determination of the model was over 0.99 which denotes that the model was quite appropriate and accurate and also it was effective in the optimization of toluene adsorption. Finally, the activated carbon adsorbent was applied to remove toluene from a real sample of wastewater under the optimal operating conditions and the uptake percentage of 96.9% was achieved which was in accordance with the output of the removal of toluene from synthetic wastewater.

Activated carbon with high mesopore ratio derived from waste Zanthoxylum bungeanum branches by KNO3-assisted H3PO4 staged activation for toluene adsorption.

Waste Zanthoxylum bungeanum branches were used to prepare activated carbon adsorbents with high mesopore ratio by H3PO4 staged activation method with adding KNO3 additive. The prepared activated carbon adsorbents were characterized by SEM, BET, FT-IR, and XRD. The adsorption properties of the prepared activated carbon adsorbents were evaluated by the toluene adsorption/desorption in air. The quasi-first-order, quasi-second-order, and Bangham models were used to fit the obtained toluene adsorption results. The oxidative etching of KNO3 additive improved the pore-forming ability of the H3PO4 activator to enhance the activation pore-forming effects of the selected biomass raw material. The secondary pore-forming effects of K atoms promoted the effective expansion of the pore diameter in the activated carbon preparation process to prepare activated carbon adsorbents with high mesopore proportion. The specific surface area and mesopore proportion of the activated carbon adsorbents prepared by adding KNO3 additive exceeded 1100 m2/g and 71.00%, respectively, and the toluene adsorption capacity exceeded 370.00 mg/g. The rich mesopore structures can effectively reduce the toluene mass transfer resistance, which can promote the corresponding activated carbon adsorbent to be regenerated by low-temperature (40 °C) thermal desorption. The toluene adsorption on the prepared activated carbon adsorbents includes surface adsorption and diffusion in pore structures, and the toluene adsorption mechanism is more consistent with the Bangham kinetic model.

High content of low molecular weight organics does not always affect pharmaceutical adsorption on activated carbon: The case of acetate, propionate and ethanol in source-separated urine

Adsorption on activated carbon is a common process to remove pharmaceuticals in wastewater treatment. Activated carbon adsorption is usually applied to wastewater with a low content of biological degradable organics, i.e. after biological treatment. Especially low molecular weight (LMW) compounds are known to compete with pharmaceuticals for adsorption sites. The goal of this study was to test the hypothesis that biological treatment is necessary for efficient pharmaceutical removal. Source-separated urine after anaerobic storage (anaerobically stored urine) and after aerobic biological removal of organics without nitrification (organics-depleted urine) were used in this study. In anaerobically stored urine 60% of the organic compounds were LMW organics, of which about 40% were acetate and propionate. 74% of the DOC and 100% of acetate and propionate were removed during aerobic biological treatment. To investigate the effect of the organic compounds on pharmaceutical removal, sorption experiments with 19 spiked pharmaceuticals and one artificial sweetener were conducted with powdered activated carbon. Ethanol, another LMW organic, was included in the study, as it is regularly used for pharmaceutical spiking thereby strongly increasing the DOC content. The experiments showed that the adsorption of the pharmaceuticals and the sweetener were hardly affected by the easily biodegradable LMW organics or ethanol. Therefore, it was concluded that biological pre-treatment is not necessary for efficient pharmaceutical adsorption. Since acetate, propionate and ethanol contribute substantially to the DOC content but do not absorb UV light, the latter is recommended as indicator for pharmaceutical removal in solutions with high contents of biodegradable LMW organics.

Efficient decolorization of oligosaccharides in ginseng (Panax ginseng) residue using ultrasound-assisted macroporous resin.

An efficient decolorization method for ginseng residue oligosaccharides (GROs) using ultrasound-assisted D392 macroporous resin was developed. The decolorization effects and color differences of activated carbon adsorption, hydrogen peroxide oxidation, and resin adsorption were evaluated. The optimal conditions of the three decolorization methods for static, dynamic, ultrasound-assisted resin adsorption were compared. The results showed that ultrasound-assisted decolorization had the best decolorization effect of greatly decreasing the decolorization time to 80min. Color difference analysis revealed the process of pigment removal during GRO decolorization. The UV-visible full-wavelength scan showed that most pigments were removed after decolorization. The characterizations by the Fourier-transform infrared spectroscopy and X-ray diffraction analysis showed that the chemical structure and crystallinity of the GROs did not change upon decolorization. In addition, the molecular weight distribution did not change significantly. This research contributes to further exploration of the structures and functions of GROs.

Pengolahan Air Limbah Tahu Menggunakan Metode Elektrokoagulasi dan Adsorpsi Secara Kontinyu

Tofu wastewater contains a lot of protein therefore it is easily degraded to produce foul odors and harmful gases due to microbes. Protein levels can be reduced through the electrocoagulation method which is equipped with adsorption. The purpose of this study is to reduce the value of turbidity, TSS, and COD in tofu wastewater due to the influence of voltage in the electrocoagulation process which is equipped with an adsorption process. This research was conducted with an electrocoagulation process at a rate of 250L/min with voltage variations of 15, 20, and 24Volt in a 10L tank containing 3 pairs of aluminum (Al) electrodes connected with direct current. The output water from the electrocoagulation process flows into the settling basin and flows into the adsorption tank containing activated carbon adsorbent. Both of these continuous processes were the innovation of this research. Sampling was conducted every 10 minutes for analysis of turbidity, TSS, COD, and pH. The results of the output water analysis from the electrocoagulation process after passing through the precipitation and adsorption processes show that increasing the voltage results in the decrease of turbidity, TSS, and COD values, however, increased efficiency and pH. Thus, a voltage of 24V with a flow rate of 250mL/min resulted in the highest efficiency of the voltage variations (15, 20, and 24V) with a process time of 90 minutes with a turbidity impurity reduction efficiency value of 45.42% with a value of 41.36 NTU from 75.22NTU, TSS 91.42% with a decrease to 1827mg/L from 21288mg/L, and COD 55.56% with a COD value of 9600mg/L from 21600mg/L, and a process output water pH of 4.91, as well as a reduction in aluminum electrode weight of 1.024grams.

Response Surface Methodology for the Optimization of Cadmium Ion Adsorption using Activated Carbon

Adsorption refers to the process of chemical species adhering to the surface of particles. Activated carbon, also known as activated charcoal, is a type of carbon widely utilized for purifying water and air by filtering out various contaminants. One of the transition metals, Cadmium (Cd), situated in the dblock and 12th group of the periodic table, possesses toxic and poisonous properties. Absorbent material was prepared using standard method. The absorbate was prepared by dissolving cadmium nitrate in distilled water. Different volume of the solution was added absorbate and later filtered and atomic adsorption Spectroscopy (AAS) was carried out. The potential of Activated carbon for removal of cadmium from contaminated water, it was found that highest efficiency in terms of percentage removal was achieved at 50 ppm initial metal ion concentration of Cadmium. The highest percentage removal was 98.5% confidence level. Therefore, the hypothesis that Activated carbon adsorbents are effective in removal of cadmium (II) ion from contaminated water at different experimental conditions is upheld