Statistical optimization of copper adsorption from aqueous solutions by sunflower waste derived activated carbon

U ovom radu za procenu efikasnosti uklanjanja bakra iz vodenih rastvora korišćen je aktivni ugalj dobijen od agroindustrijskog otpada suncokreta. Boks-Benkenov dizajn i metoda odzivne površine korišćeni su za optimizaciju procesnih parametara adsorpcije kao i međusobni uticaj varijabli na efikasnost uklanjanja. Sintetizovani aktivni ugalj primenjen je za uklanjanje bakra iz realnog uzorka otpadne vode, a dobijeni rezultati ukazuju na veliki afinitet za separaciju bakra (98,6% ± 2,0%).In this work, activated carbon obtained from sunflower agro-industrial waste was used to evaluate the removal efficiency of copper from aqueous solutions. The Box-Behnken design combined with the response surface method was employed to optimize the adsorption process parameters as well as the mutual influence of the variables on removal efficiency. The synthesized activated carbon was applied to remove copper from a real wastewater sample, and the obtained results indicate a high affinity for copper separation (98,6% ± 2,0%).59th Meeting of the Serbian Chemical Society; June 1-2, 2023, Novi Sad, Serbi

Highly microporous sunflower-derived activated carbon for lead and copper removal: Synthesis, characterization, and adsorption mechanism

Different industrial processes can potentially discharge heavy metals into surface and underground waters. These heavy metals can subsequently accumulate in organisms, posing a significant risk to both the environment and human health. Carbon-based materials such as biochar, carbon nanotubes-based materials, and activated carbon have been extensively researched for their effectiveness in adsorbing heavy metals from aqueous solutions [1]. Today, there is an increased interest in the usage of different low-cost, abundantly available lignocellulosic waste as a precursor for the production of activated carbon material. Activated carbon materials produced from different types of agricultural waste are widely used as adsorbent material for the removal of organic and inorganic pollutants from wastewater. High adsorption capacity is associated with characteristics of the adsorbent such as a large specific surface area, pore structure development, and the presence of different types of functional groups [2]. In this work, activated carbon is produced by the carbonization of sunflower agricultural waste followed by an activation process with potassium hydroxide. Activated carbon samples were characterized by SEM-EDS, BET, FTIR, and XPS. The obtained material has a porous structure with micropores and a large specific surface area, exhibiting a high affinity for the adsorption of lead and copper. Additionally, the main mechanism of lead and copper adsorption by sunflower-derived activated carbon has been successfully predicted

Efficient removal of priority, hazardous priority and emerging pollutants with Prunus armeniaca functionalized biochar from aqueous wastes: Experimental optimization and modeling

This paper investigates the ability of the phosphoric acid functionalized Prunus armeniaca stones biochar (AsPhA) prepared by thermochemical activation to remove lead (Pb2+), cadmium (Cd2+), nickel (Ni2+), naproxen and chlorophenols from aqueous wastes. The engineered biochar was characterized using the Scanning Electron Microscopy, Energy-dispersive X-ray Spectroscopy, Fourier Transform Infrared Spectroscopy and Brunauer, Emmett and Teller technique. The batch studies were performed by varying the initial pH of the solution (2-9), adsorbent dosage (0.2-10 g L-1), contact time (5-60 min), temperature (22, 32 and 42 degrees C) and initial adsorbate concentration (5-500mg L-1). With the optimal process conditions, the adsorption efficiency was over 95% (100 mg L-1). The results were fitted with three kinetic and three equilibrium theoretical adsorption models. The adsorption process has good correlation with pseudo-second-order reaction kinetics. Adsorption mechanism was found to be controlled by pore, film and particle diffusion, throughout the entire adsorption period. The monolayer adsorption capacities were found to be 179.476, 105.844 and 78.798mg g(-1) for Pb2+, Cd2+ and Ni2+, respectively. Thermodynamic parameters such as Gibbs energy, enthalpy and entropy were also calculated. Additionally, preliminary results indicated a strong affinity of the biochar for selected organic micropollutants: naproxen and chlorophenols. Based on desorption study results, biochar was successfully regenerated in 3 cycles with diluted phosphoric acid produced as a waste stream during washing of the biochar after thermochemical activation. The experimental results were applied in a two-stage completely stirred tank reactor design. Cost estimation of AsPhA production substantiated its cost effectiveness and adsorption costs of selected pollutants were 5 times lower than with the commercial activated carbons. Based on the low-cost and high capacity, engineered biochar can be used as a highly efficient eco-friendly adsorbent for removal of heavy metal and organic micropollutants from wastewaters systems

Substrate-driven phosphorus bioavailability dynamics of novel inorganic and organic fertilizing products recovered from municipal wastewater : tests with ryegrass

Municipal wastewater is a valuable source of phosphorus (P) for the production of fertilizing products, such as microalgae (MA), crab carapace material (CCM), P salt produced by chemical leaching of sludge (P salt CL), and sewage sludge ash produced by pyrolysis and the incineration of sludge (SSA PI). This study compares the P availability of these fertilizing products in three planting substrates (S1, S2, and S3) during a four-month growth period of perennial ryegrass. The unfertilized control in substrate S3 had a high and available P that masked the effect of the added fertilizing products. The P salt CL fertilizer exhibited the lowest shoot dry matter in the alkaline S2 substrate. Still, it can be used as a good source of P in both acidic and alkaline substrates, given that its shoot P content was among the highest in all substrates tested. The organic-rich fertilizing products, MA and CCM, are better suited for acidic substrates since a pronounced reduction in the shoot yield and P content was seen in the alkaline S2 substrate. In contrast, for the SSA PI fertilizer, the very small differences in shoot dry matter and P content in S1 compared to S2 indicated that it is suitable for both acidic and alkaline substrates. Four months were needed to observe the maximum shoot yields treated with these P fertilizing products. Considering that the substrate solution P (using Rhizons) for the P salt CL and MA fertilizers proved to be similar to shoot P uptake, Rhizon extraction could be used for assessing P bioavailability. The chemical composition of novel products indicated their potential to deliver not only P, but also other nutrients to plants. However, concentrations of inorganic contaminants in all products, except CCM, pointed out a possibility to pollute the environment by applying these fertilizers

Utilization of fruit processing industry waste as green activated carbon for the treatment of heavy metals and chlorophenols contaminated water

Plum stones, as a part of industrial and municipal organic waste, were used as a precursor for preparation of a low-cost activated carbon. Engineered, thermochemically-modified adsorbent was used to remove lead (Pb2+), cadmium (Cd2+), nickel (Ni2+) and chlorophenols from an aqueous solution. The characterization of the medium was performed using standard instrumental analysis. Additionally, the assessment included the influence of pH, adsorbent dosage, temperature, contact time and initial metal concentration on the separation efficiency in the batch-operational mode. With optimal working conditions, the process efficiency of over 95% was accomplished. The equilibrium and kinetic studies of adsorption were done. The pseudo-second order model described the adsorption kinetics best. The maximum adsorption capacity of the engineered adsorbent for Pb2+, Cd2+ and Ni2+ ions was calculated from the Langmuir isotherms and found to be 172.43 mg g(-1), 112.74 mg g(-1) and 63.74 mg g(-1), respectively. Preliminary results indicate a strong affinity of the separation medium for chlorophenols. Thermodynamic parameters such as Gibbs energy, enthalpy and entropy were calculated. Regeneration of the saturated adsorbent was conducted, with diluted phosphoric acid produced as a waste stream, during the washing of the adsorbent after activation. Based on the desorption study results, the activated carbon was successfully regenerated in 3 cycles. Mutual influence of ions was analyzed in multicomponent systems. The real system production and operational costs analysis confirmed a possibility for a successful implementation of the highly efficient, eco-friendly engineered adsorbent in the field of cost-effective wastewater treatment.The peer-reviewed version: [http://cer.ihtm.bg.ac.rs/handle/123456789/2942

Waste biomass derived highly-porous carbon material for toxic metal removal: Optimisation, mechanisms and environmental implications

Toxic elements, lead, and copper are often found in wastewater discharged from industries such as mining. The discharge of untreated effluent poses severe environmental challenges and sorption methods using agricultural waste materials are proposed as an efficient and cost-effective solution. For this research, activated sunflower material (ASM) was prepared from abundantly available agricultural sunflower waste residues and utilised to remove Pb2+ and Cu2+ ions from an aqueous medium. To begin, we examine variables that may have an impact on the adsorption process, such as pH, contact time, adsorbent dose, and initial concentration using Box-Behnken Design (BBD) to find optimal conditions. Maximum removal efficiency was found at a pH of 5, contact time of 180 min, and initial concentration of 50 mg/L for Pb2+ and 150 mg/L for Cu2+. Additionally, adsorbent dose differed by element, for Cu2+ it was 200 mg, whilst for Pb2+ it was 124 mg. Features of activated carbon such as morphology, elemental composition, textural properties, and surface functionalities were characterised using SEM-EDS, BET, FTIR, and XPS. The adsorption equilibrium data were analysed by Langmuir, Freundlich, and Dubinin-Radushkevich isotherm models. It was found that the obtained results for Pb2+ adsorption were better described with the Freundlich isotherm model. Maximum adsorption capacities for Pb2+ and Cu2+ were 91.8 mg/g and 20.5 mg/g, respectively. Furthermore, kinetic studies confirmed that the adsorption process followed a pseudo-first-order kinetic model for Pb2+, but for Cu2+ all applied kinetic models fitted experimental data with the same values of the correlation coefficient (R2 = 0.99). After comprehensive analysis using the methods mentioned above, ASM was tested for the removal of Cu2+ from mining wastewater sample, and the obtained removal efficiency was 98.6% ± 2.0%. The results of desorption experiments conducted, confirm that ASM has good potential to be reused for the purpose of removing Cu2+ from wastewater