Adsorbent In Adsorption Process Research Articles

Synthesis, characterization, and phosphorus adsorption of Mg/Fe-modified biochar from cotton stalk pretreated with Coriolus versicolor.

In recent years, the research potential in utilizing biochars as adsorbents in adsorption processes has grown due to their eco-friendly and economical nature. However, biochar often possesses a negative surface charge that limits its affinity for binding anions. Nitric acid washing and pretreatment with Coriolus versicolor can break down the lignocellulosic structure in cotton stalk waste, facilitating the subsequent impregnation of Mg and Fe metal oxides. These pretreatment steps can lead to the production of diverse and functionalized biochars with higher adsorption capacities. In this study, cotton stalk waste was first washed with diluted nitric acid and then subjected to biological pretreatment by incubation with C. versicolor, followed by impregnation with Mg and Fe to obtain CV-CS/Fe and CV-CS/Mg biochars. The results showed that the applied pretreatments altered the physicochemical properties and significantly increased the phosphorus adsorption capacity. The adsorption capacities of CV-CS/Fe and CV-CS/Mg biochars were found to be 277.88 and 507.01 mg g-1, respectively. The results indicate that the incorporation of multiple metal oxide impregnates enhances P adsorption. Furthermore, in the kinetic study, pseudo-first-order and pseudo-second-order models provided a well fit, determining chemical adsorption as the main adsorption mechanism for phosphorus adsorption. The biochars demonstrated compatibility with Langmuir-Freundlich models. Overall, the findings suggest the possibility of synthesizing biochars with improved adsorptive properties through pretreatment, and these engineered biochars hold promising potential as effective adsorbents in the field. PRACTITIONER POINTS: Eco-friendly, natural, and economical biochar was synthesized. Biochar was produced via Coriolus versicolor pretreatment. High adsorption capacities of CV-PS/Mg biochars were found to be 507.01 mg g-1. Adsorption capacities of biochars can be improved by pretreatment.

Removal of COD and Ammoniacal-Nitrogen from Industrial Wastewater using Adsorption with Plantain Husk Adsorbent

The rate of depletion of ground/surface water has increased due to the weakness in the existing laws, contamination of the ground water and excess usage of water that produce increased quantity of wastewater. In this study, wastewater from Dangote Fertilizer Limited (DFL) was treated using adsorption method of treatment with consideration of the factors (pH, temperature and contact time) that impedes the efficiency of the method. Plantain husk, which is an agricultural waste, was used as adsorbent in the adsorption process. Response Surface Methodology (RSM) was used to determine the experimental number of runs after which it gives the optimum conditions of those parameters considered. The plantain husk was characterized using Gas chromatograph with Flame Ionization detector (GC-FID). The results obtained in the study revealed that utilization of the plantain husk as adsorbent in adsorption process for the removal of COD and Ammoniacal nitrogen from industrial wastewater will yield a high percentage removal (values). Ammoniacal nitrogen removal with plantain husk adsorbent was about 93% maximum and as pH increased to 7.5 (alkaline), a slight decrease in the Ammoniacal nitrogen removal percentage to about 92% could be attained. Furthermore, percentage removal of COD from the wastewater of about 83% maximum could be obtained. Effect of temperature on COD removal is a direct correlation as increase in temperature could lead to the decrease in COD removal. It can be concluded that the interaction between contact time and pH as compared to other interactions has an overall positive effect in the adsorption process of Ammoniacal nitrogen removal from wastewater. Being an agricultural waste and environmentally friendly materials, adsorbent from plantain husk should be considered for treatment of industrial waste water for removal of COD and ammoniacal nitrogen.

Production of chemically and microwave activated hazelnut husk as an adsorbent for dye contaminated wastewaters

Adsorption has traditionally been evaluated as an economical and easily applicable process for treating certain wastewaters, such as ones including dyes and heavy metals. Even though adsorbent materials specifically produced for the purpose of wastewater treatment commercially exist, the production cost may create an economic burden on wastewater treatment processes. Agricultural wastes can be valorized as adsorbents in adsorption processes. The adsorption capacity of these wastes can be improved via pre-treatment methods such as chemical application and microwave irradiation. This study investigated the potential applicability of hazelnut husk as an adsorbent for methylene blue (MB) dye. To this purpose, the husk was activated by sequential chemical or water and microwave applications. Structural analysis on the produced adsorbent was performed by Fourier transform infrared spectrophotometry (FTIR) and field emission scanning electron microscopy (FE-SEM). Isotherm (Langmuir, Freundlich, Temkin and Harkins-Jura isotherms) and kinetic (pseudo-first-order, pseudo-second-order, Elovich and intraparticle diffusion kinetic models) behaviours of adsorption were also evaluated. The results indicated that MB could be removed by 92-94% considering all adsorbents produced. Further isotherm and kinetic studies revealed that MB adsorption was both physically and chemically induced, and the reaction followed the pseudo-second-order kinetic model (R2>0.99).

Lifting removal of cationic dye (methylene blue) from wastewater by improving Zr-MOFs via second metal Al coordination

Metal organic frameworks (MOFs) are frequently used as adsorbents in adsorption processes to remove dyes from effluent produced by the textile industry. Today, dye contaminants have become an important environmental problem. One of these dyes is methylene blue (MB) and its removal from wastewater is a priority because it is persistent and nondegradable. MB is used in many industries although it has potential harmful effects on human and aquatic life and can be considered a hazardous chemical when in wastewater. The present study shows the potential applications for enhanced forms of UiO-66 MOFs, such as UiO-66, UiO-66-10%Al and UiO-66-30%Al. These forms were prepared to remove MB from wastewater using batch experiments. Characterisation of adsorbents were accomplished successfully using Fourier transform infrared, X-ray powder diffraction, Brunauer–Emmett–Teller surface area and thermogravimetric analysis techniques. To investigate equilibrium adsorptive behaviour, Langmuir and Freundlich isotherm models were tested against the experimental data. Based on linear regression correlation coefficient (R2), the Freundlich model described the equilibrium isotherm of MOF/MB better than the Langmuir model. Of all forms of UiO-66 MOF, UiO-66-10%Al had the maximum Langmuir adsorption capacity at 49.26 mg/g. A kinetics study examined pseudo first-order, pseudo second order and Elovich models to determine which could explain the sorption mechanism. While the pseudo second order and Elovich models showed a good fit with the experimental data, the correlation coefficient of the pseudo second-order model was the highest. These results indicate that adsorption of MB is controlled by a chemisorption mechanism. Further, intraparticle diffusion was utilised to describe the adsorption mechanism and determine the rate-limiting steps in the adsorption process.

Development of adsorption-biodegradation hybrid process for removal of methylene blue from wastewater

This study demonstrates the removal of methylene blue dye contained in wastewater through a hybrid process combining the adsorption with biodegradation process. The coconut shell biochar, prepared by pyrolysis of coconut shell; an economical and agricultural waste, was utilized as adsorbent. The biochar of coconut shell obtained from pyrolysis was used as an adsorbent for adsorption process. Simultaneously, bacterial species was successfully isolated from textile waste leachate, which was identified as Alcaligenes species. Adsorption process parameter such as adsorbent dosage (0.5 g/L) and pH (10) were optimized for hybrid process. The continuous operation was performed in hybrid bioreactor up to 40days. The performance of hybrid process was studied in respect to COD loading and with the percentage removal efficiency of methylene blue. The maximum percentage removal of methylene blue by the hybrid process was 88.01% at loading rate 105.52 mg/L day for methylene blue removal. The residual analysis was performed by FTIR and GC–MS to verify the degradation of methylene blue.

High performance removal of phenol from aqueous solution by magnetic chitosan based on response surface methodology and genetic algorithm

The magnetic chitosan was prepared and characterized using FT-IR, SEM, and XRD techniques. The adsorbent was used for uptake of phenol in water. The sorption was modeled based on central composite design (CCD) - response surface methodology (RSM) method for independent variables pH, time, adsorbent dosage and phenol concentration; suggesting a quadratic polynomial model with p-value < 0.001, R2 = 0.9983 and adjusted R2 = 0.9963. The optimization of input factors was conducted using both CCD-RSM and Algorithm Genetic (GA). The obtained results were the same, where the optimum level of pH, time, adsorbent dosage, and phenol concentration for CCD-RSM technique were 3, 50 min, 0.96 g/L and 15 mg/L, and for GA technique were 3, 50 min, 1 g/L and 15 mg/L. In this condition, maximum removal was 97% for both CCD-RSM and GA. The isotherm and kinetic studies of adsorption process illustrated that adsorption of phenol onto magnetic chitosan corresponded Freundlich isotherm and Intraparticle diffusion kinetic models. The maximum adsorption capacity was approximately 51.68 mg∙g−1. Thermodynamic studies identified exothermic nature of adsorption. It was concluded that magnetic chitosan is a potential and promising adsorbent in adsorption process of phenolic pollutants and similar compounds from aquatic environments.

Chitosan Beads as an Adsorbent for the Removal of Colour from Natural Rubber Wastewater

Natural rubber processing wastewater contains high concentration of organic compound, colour, nitrogen, and other contaminants. This study evaluated a chitosan bead as an adsorbent in adsorption process for natural rubber wastewater treatment. The effects of adsorbent dosage, pH, shaking speed and contact time and adsorption isotherm on colour adsorption onto chitosan beads were evaluated using batch experiments. Meanwhile, Langmuir and Freundlich isotherm models were used to validate the experimental data. Maximum removal of 71.5%, for colour was observed for an adsorbent dosage 4.5 g, pH 7, and shaking speed 150 rpm. Equilibrium was achieved in 120 min. The equilibrium data were fitted to Langmuir isotherm model when compared with Freundlich isotherm models.

Use of TiO2 and Rice Husk Ash to study the removal of Reactive Yellow Dye as contaminant in water

The presence of dyes in the water sources is nowadays a well-established issue and has become a matter of both scientific and public concern. Processes such as advanced oxidation process (AOP) and adsorption has proved useful in the treatment of such emerging contaminants. In this study, commercially available nanomaterial Tio2 (size 25 nm) and rice husk ash (RHA) was used to check the removal efficiency for the trace water contaminant namely, reactive yellow dye (RYD), which is a commonly used textile dye. In this study, TiO2, a photoactive compound, was used as a catalyst in AOP and as an adsorbent in adsorption process. Comparison was made for removal efficiency between TiO2 as a catalyst and as an adsorbent. Experiments were conducted by varying the parameters such as dye concentration, pH, TiO2 concentration and reaction time to study the removal of dye. Batch Adsorption Test was conducted by employing TiO2 as adsorbent. Comparative studies were done by employing rice husk ash (RHA) also as adsorbent. It was found that for an initial concentration of 10mg/l of RYD, 87.5% removal was achieved at a pH of 3, TiO2 10mg/l for a time period of 60 minutes using AOP. For 50mg/l RYD concentration, adsorption using RHA and TiO2 was performed.

Montmorillonite Nanoparticles in Removal of Textile Dyes from Aqueous Solutions: Study of Kinetics and Thermodynamics

Dyeing wastewaters are one of the most common pollutants that cause many problems for public health and environment due to dermatitis and skin rashes, cancer production, mutagenesis, etc. Thus, treatment of these wastewaters is necessary. The purpose of this study was to investigate the efficiency of montmorillonite nanoparticles as an adsorbent in adsorption process of Reactive Yellow 15 (RY15) and Reactive Yellow 42 (RY42) dyes from aqueous solutions. In this study, montmorillonite nanoparticles were used to remove RY15 and RY42 dyes. The effect of different variables such as pH, contact time, dye concentration and adsorbent dosage was studied. Finally, the effect of process temperature and thermodynamic was studied. Also, pseudo-first and second orders of kinetics were studied. The results showed that 3 is the best pH for the removal of both dyes. As contact time increases to 15 minutes, adsorption capacity increases and then reaches an approximately constant value. Adsorption capacity was also increased with increased dye concentration. By changing the adsorbent dosage from 0.2 to 0.6 g/L, adsorption capacity for RY15 and RY42 was reduced from 142and 166 to 63 and 59 mg/g, respectively. The results also showed that both dyes had the highest correlation with pseudo-second-order kinetics. The results of analyzing the process thermodynamics and temperature showed that values of DH, DS and DG are negative for both dyes.

Valorization of Paper Mill Sludge as Adsorbent in Adsorption Process of Copper (II) Ion from Synthetic Solution: Kinetic, Isotherm and Thermodynamic Studies

This study investigates the process conditions of the adsorption of copper (II) ion onto paper mill sludge (PMS) in a batch process. These conditions are: concentration of initial solution, contact time, temperature and quantity of the adsorbent. Characteristic properties of PMS employed as an adsorbent in the experiments were defined using Fourier transform infrared spectroscopy (FT-IR) scanning electron microscopy (SEM) and elemental analyses. According to the obtained results, while the amount of removed copper (II) ion increased with an increase in the rate of the adsorbent and contact time, it decreased as a result of an increase in the temperature and initial solution concentration. Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherms were implemented for the determination of the most appropriate isotherm model for the experimental data, and it was found that the process is in concordance with Langmuir equation. The maximum adsorption capacity of PMS was calculated as 114.42 mg g $$^{-1}$$ . In kinetic studies, the adsorption process of copper (II) ion onto PMS was controlled by the pseudo-second-order kinetic model. The calculated activation value ( $$E_{\mathrm{a}})$$ was 38.61 kJ mol $$^{-1}$$ and demonstrates that the process occurred by physical adsorption mechanism. The values of the thermodynamic parameters such as enthalpy ( $$\Delta {H}^{{{ O}}})\,(-21.19\,\hbox {kJ\,mol}^{-1})$$ , free energy ( $$\Delta {G}^{\mathrm{O}}$$ ) (−8.883 kJ mol $$^{-1}$$ ) and entropy ( $$\Delta {S}^{\mathrm{O}})$$ (0.101 kJ mol $$^{-1}$$ K $$^{-1}$$ ) changes were determined to estimate the nature of the process. The results clearly showed that the process was of exothermic and spontaneous nature and that PMS could be utilized as an adsorbent for the removal of copper (II) ion from wastewater.

A review on progress of heavy metal removal using adsorbents of microbial and plant origin.

Heavy metals released into the water bodies and on land surfaces by industries are highly toxic and carcinogenic in nature. These heavy metals create serious threats to all the flora and fauna due to their bioaccumulatory and biomagnifying nature at various levels of food chain. Existing conventional technologies for heavy metal removal are witnessing a downfall due to high operational cost and generation of huge quantity of chemical sludge. Adsorption by various adsorbents appears to be a potential alternative of conventional technologies. Its low cost, high efficiency, and possibility of adsorbent regeneration for reuse and recovery of metal ions for various purposes have allured the scientists to work on this technique. The present review compiles the exhaustive information available on the utilization of bacteria, algae, fungi, endophytes, aquatic plants, and agrowastes as source of adsorbent in adsorption process for removal of heavy metals from aquatic medium. During the last few years, a lot of work has been conducted on development of adsorbents after modification with various chemical and physical techniques. Adsorption of heavy metal ions is a complex process affected by operating conditions. As evident from the literature, Langmuir and Freundlich are the most widely used isotherm models, while pseudo first and second order are popularly studied kinetic models. Further, more researches are required in continuous column system and its practical application in wastewater treatment.

Application of Metal Oxide Heterostructures in Arsenic Removal from Contaminated Water

It has become one of the major environmental problems for people worldwide to be exposed to high arsenic concentrations through contaminated drinking water, and even the long‐term intake of small doses of arsenic has a carcinogenic effect. As an efficient and economic approach for the purification of arsenic‐containing water, the adsorbents in adsorption processes have been widely studied. Among a variety of adsorbents reported, the metal oxide heterostructures with high surface area and specific affinity for arsenic adsorption from aqueous systems have demonstrated a promising performance in practical applications. This review paper aims to summarize briefly the metal oxide heterostructures in arsenic removal from contaminated water, so as to provide efficient, economic, and robust solutions for water purification.