Non-conventional Adsorbents Research Articles

Removal of Azo Dyes from Water Using Natural Luffa cylindrica as a Non-Conventional Adsorbent.

Reducing high concentrations of pollutants such as heavy metals, pesticides, drugs, and dyes from water is an emerging necessity. We evaluated the use of Luffa cylindrica (Lc) as a natural non-conventional adsorbent to remove azo dye mixture (ADM) from water. The capacity of Lc at three different doses (2.5, 5.0, and 10.0 g/L) was evaluated using three concentrations of azo dyes (0.125, 0.250, and 0.500 g/L). The removal percent (R%), maximum adsorption capacity (Qm), isotherm and kinetics adsorption models, and pH influence were evaluated, and Fourier-transform infrared spectroscopy and scanning electron microscopy were performed. The maximum R% was 70.8% for 10.0 g L-1Lc and 0.125 g L-1 ADM. The Qm of Lc was 161.29 mg g-1. Adsorption by Lc obeys a Langmuir isotherm and occurs through the pseudo-second-order kinetic model. Statistical analysis showed that the adsorbent dose, the azo dye concentration, and contact time significantly influenced R% and the adsorption capacity. These findings indicate that Lc could be used as a natural non-conventional adsorbent to reduce ADM in water, and it has a potential application in the pretreatment of wastewaters.

Think before throw: waste chili stalk powder for facile scavenging of cationic dyes from water.

Chili stalk powder (CS), a non-conventional adsorbent, has been exercised for facile removal of cationic dyes from simulated and wastewater by batch technique. The prepared material has been characterized by Fourier-transform infrared spectroscopy (FTIR), Field emission scanning electron microscopy (FESEM), Brunauer-Emmett-Teller analysis (BET), powder X-ray diffraction (powder XRD), and pHZPC and tested best with methylene blue and crystal violet under ambient conditions. FTIR denotes the presence of carbonyl and polyphenolic groups, responsible for dye adsorption. BET surface area analysis evaluates the porous nature and specific surface area of the material, and powder XRD confirms its amorphous nature. The porous structure could be ascertained from the FESEM image, and energy dispersive X-ray analysis (EDX) confirms the elemental composition. The pH above pHzpc shows an increase in removal efficiency. The maximum adsorption capacities are 49.53 and 36.88mg/g for methylene blue (MB) and crystal violet (CV) respectively. Linear as well as non-linear plots for kinetic and isotherm models were studied. Both dye uptake fits the linear plot of Langmuir adsorption isotherm (R2 = 0.999 and 0.995) and pseudo-second-order kinetics (R2 = 0.998 and 0.999). In the non-linear plot, the adsorption process for both dyes fit Langmuir (R2 = 0.999 for MB and R2 = 0.983 for CV) as well as Freundlich adsorption (R2 = 0.999 for MB and R2 = 0.994 for CV). 75.48% crystal violet (CV) and 73.35% methylene blue (MB) regeneration were successful in 1:1 methanol medium and reused for up to three cycles. The uptake mechanism is suggested to be a union of π-π stacking, electrostatic interaction, and weak hydrogen bonding. The material was tested with industrial effluent to prove its application in real wastewater treatment. Moreover, the material shows superior adsorption capacity than contemporary phytosorbents. To conclude, a zero-cost adsorbent using green chili stalk has been demonstrated for wastewater treatment.

Efficient fabrication of pH-modified graphene nano-adsorbent for effective determination and monitoring of multi-class pesticide residues in market-fresh vegetables by GC-MS

Toxic pesticide residues in edible vegetables cause major health risks for consumers, hence quantifying them is essential. However, simultaneous and trace level determination of xenobiotic residues of various classes in complex food matrices is still a challenging analytical task. In this experiment, reduced graphene oxide (RGO-B), a carbon nano-structure with stunning adsorbent properties and ultrahigh surface area (pore size ∼6 Å) was efficiently (≥96%) synthesized via pH-controlled reduction process and characterized by ultraviolet-visible (UV–VIS) spectrophotometer, X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM) and Fourier Transform Infrared (FTIR). Adsorption efficiency of different pH-regulated RGOs was studied in terms of dye (Malachite Green) removal percentage. Two-dimensional carbon (sp2) RGO was used as a dispersive solid-phase extraction adsorbent in a modified QuEChERS method in combination (4:1) with primary secondary amine (PSA) to extract 28 multi-class pesticides (OC, OP, SP) from chilli, cabbage, tomato, and cucumber. The experimental results established the best extraction ability and adsorption capacity of RGO over traditional and high-cost adsorbents. Moreover, the introduction of graphene has helped improve the percent recovery (75.36–118.32%) with acceptable (<12.8%) relative standard deviation (RSD) at limits of quantification (LOQs) (S/N = 10:1) levels of 0.01–0.1 mgL−1. Gas chromatography-mass spectrometry (GC-MS)-based multi-pesticide analytical method was successfully validated as per SANTE/12682/2019 guidelines for monitoring 144 market-fresh vegetables in West Bengal, India. The analysis results indicated that eight (8) samples (5.55%) were contaminated with toxicants 5–10 times higher than the European Union Maximum Residue Limits (EU-MRLs). Matrix removal abilities and cost analysis proved that graphene has significant prospects as an expectant non-conventional adsorbent for low-cost (53.3% cheaper) pesticide residue analysis.

Facile synthesis of eco-friendly activated carbon from leaves of sugar beet waste as a superior nonconventional adsorbent for anionic and cationic dyes from aqueous solutions

The current study presents a unique and innovative approach to sustainable activated carbon (AC) synthesis using non-conventional agricultural wastes, leaves of sugar beet (LSB), via a thermo-chemical activation process. This approach not only offers a sustainable solution for LSB elimination, but also provides an eco-friendly alternative to commercially available activated carbon. The thermo-chemical activation process was conducted at various ratios of H3PO4 / LSB (0.5:1, 1:1, 2:1, and 3:1 w/w ratios) at a fixed temperature (550 °C/2h). The unique amorphous nature, porous structure, BET surface area (SBET = 700.7 m2/g), and surface chemistry nominated the synthesized AC at 2:1 ratio as a superior adsorbent material for methyl orange, MO, and methylene blue, MB, from standard solutions in the batch system at different experimental conditions. Kinetic investigations revealed that the pseudo-second order equation explained the sorption data well. In contrast, intra-particle diffusion was not the only limiting stage in the adsorption of the addressed dyes. Similarly, the linear Langmuir equation described the adsorption data of the investigated dyes better than Freundlich one with maximum removal capacity (qmax) of 185.2 and 140.8 mg/g for MB and MO, orderly. This confirms the homogenous/monolayer nature of the adsorbed ions through isoenergetic active sites upon the AC(2:1) surface. Furthermore, the electrostatic attraction was not the only leading mechanism of adsorption of both dyes, but substantial participations by hydrophobic hydrogen-bonding forces may be considered.

Malachite Green Adsorption Using Carbon-Based and Non-Conventional Adsorbent Made from Biowaste and Biomass: A Review

Malachite Green Adsorption Using Carbon-Based and Non-Conventional Adsorbent Made from Biowaste and Biomass: A Review

Methylene Blue Dye Adsorption in Aqueous System using Microcrystalline Cellulose obtained from Sugarcane Bagasse

Microcrystalline cellulose (MCC) was prepared from sugarcane bagasse (SCB) after alkali extraction with sodium hydroxide (NaOH). The prepared MCC was treated with methylene blue solution. Batch experiments were performed to investigate the effect of contact time, initial dye concentration, pH and adsorbent dosage on methylene blue adsorption. The result shows that the adsorption of methylene blue dye onto the adsorbent was influenced by adsorbent dose, dye concentration, contact time and pH values. For higher removal of dye from simulated wastewater, adsorbent dose of 0.4g and dye concentration of 200 mg/l gave optimum adsorption with percentage removal (% R) of 87.19. The adsorption capacity of methylene dye increased with increase in contact time. Also, the duration and pH for optimum adsorption were at 120 mins and pH 9 respectively. The experiment data fitted well into Freundlich isotherm. The results of this work revealed that microcrystalline cellulose from sugarcane bagasse is a potential alternative non-conventional adsorbent for treating dye effluent.

Treatment of Textile Dyeing Effluent Using Agriculture Waste Based Adsorbents - A Review

Objective: Removal of colour from the textile dyeing effluent is a major problem due to high tinctorial value, complex structure of the dyes, toxicity and presence of metals in some dyes. The colouring matter has to be removed from the effluent before its discharge as it constitutes the major fraction of pollution. The spent dyes in the textile effluent have to be removed before disposal as they constitutes major fraction of pollution. Review of waste based adsorption of the spent dyes, performance, economics involved and disposal options for the spent adsorbents are the objectives of the present work.&#x0D; Methods: Various techniques are used for the removal of colour including adsorption. Although the activated carbon is an ideal adsorbent, it is expensive for effluent treatment due to its high production and regeneration costs. High cost of activated carbon has led to the search for alternate non-conventional adsorbents. Attempts have been made by researchers to use the non-conventional, low-cost and naturally occurring waste materials as adsorbents. The findings are based on literature survey and authors’ experience.&#x0D; Findings: This review seeks to give an overview of the agriculture waste based adsorbents together with physical and chemical processing needs, adsorption parameters including mechanisms and the adsorption potential of various adsorbent-adsorbate systems for removal of different dyes from the effluents. Comparative studies conducted with synthetic effluents as well real textile dyeing effluent are also included. The cost involved in the dyeing effluent treatment is always a concern for the textile dyeing industries. The cost issue can be addressed using the waste based adsorbents for which an economics have been presented.&#x0D; Conclusion: The gaps between practices and the present research works have been identified and highlighted along with further research needs for treatment of the dyeing effluents. The waste based adsorbents are mainly agricultural residues and combustible. The spent adsorbents can be reused as fuel in the boiler furnace that can offset the expenses on fuel to some extent.

Comparative adsorption study of mango (&lt;em&gt;Mangifera indica&lt;/em&gt;) leaves and neem (&lt;em&gt;Azadirachta indica&lt;/em&gt;) leaves, as an adsorbent for dye removal

The study attempted to evaluate and compare the adsorption capacity (Methylene Blue removal) of non-conventional adsorbents prepared from Neem (<em>Azadirachta indica</em>) leaf and Mango (<em>Mangifera Indica</em>) leaf and Langmuir model or Freundlich model were analyzed. The leaves from Neem and Mango were collected, cleaned, dried (115°C) and powdered. The physiochemical properties were studied. Methylene blue dye was used as the pollutant since it is a frequently used dye for adsorption studies. A series of batch experiments were carried to evaluate the adsorption capacity of Neem leaf adsorbent and mango leaf adsorbent with different dosages and different initial adsorbate concentrations (100, 150, 200 and 250 mg/L). Neem leaf showed the highest adsorption capacity of 83%. The adsorption capacity of the Mango leaves was around 79%. Adsorbent dose and adsorption rate have a positive relation. Adsorption rate increases with adsorbent dose and decreases with increases of adsorbate initial concentration. Langmuir isotherm showed a high coefficient of determination. Both Langmuir separation factor (RL) and Freundlich constant (nF) suggest the favorable adsorption of the dye onto the adsorbents. The results indicated that both neem and mango leaves have an attractive property to remove dye from water. Therefore, both can be used as alternative green adsorbents for pollutant removal.

Removal of emerging contaminants from wastewater using advanced treatments. A review

The rise of emerging contaminants in waters challenges the scientific community and water treatment stakeholders to design remediation techniques that are simple, practical, inexpensive, effective, and environmentally friendly. Emerging contaminants include antibiotics, hormones, illicit drugs, endocrine disruptors, cosmetics, personal care products, pesticides, surfactants, industrial products, microplastics, nanoparticles, and nanomaterials. Removing those contaminants is not easy because classical wastewater treatment systems are not designed to handle emerging contaminants, and contaminants often occur as traces in complex organo-mineral mixtures. Here, we review advanced treatments for the removal of emerging contaminants in wastewater, with focus on adsorption-oriented processes using non-conventional adsorbents such as cyclodextrin polymers, metal–organic frameworks, molecularly imprinted polymers, chitosan, and nanocellulose. We describe biological-based technologies for the degradation and removal of emerging contaminants. Then, we present advanced oxidation processes as the most promising strategies because of their simplicity and efficiency.

Application of Cationic Surfactant Modified Mengkuang Leaves (Pandanus atrocapus) for the Removal of Reactive Orange 16 from Batik Wastewater: A Column Study

The feasibility of Mengkuang leaves (Pandanus atrocarpus) as a non-conventional low-cost adsorbent for the removal of an anionic dye, Reactive Orange 16 (RO16), was investigated. Among the dyes that have been commonly used in the Batik industry was reactive dye. In this study, Mengkuang leaves were chemically modified with cetyltrimethylammonium bromide (CTAB), a cationic surfactant, to improve their adsorption performance toward anionic dyes. The adsorbent’s morphological characteristics were analyzed using a scanning electron microscope (SEM). The surface of modified Mengkuang leaves seems to be irregular and uneven, with more porous structures than raw Mengkuang leaves. Adsorption of RO16 dye in fixed bed column using modified Mengkuang leaves adsorbent indicated the breakthrough time increased at higher bed height and lower flow rate. The breakthrough times for bed height of 0.5, 2, and 4 cm were at 16, 68, and 165 min, respectively. Meanwhile, breakthrough time for the flow rate of 2,5 and 7 mL.min-1 were at 327, 104, and 43 min, respectively. However, the study utilizing raw Mengkuang leaves showed no significant removal of RO16. Thus, it can be concluded that the cationic surfactant modification of Mengkuang leaves is advantageous for anionic dye removal. This anionic dye removal is significantly influenced by column parameters such as bed height and flow rate as the plotted breakthrough curves obtained from experimental data were similar to the typical breakthrough curve. When applied to the Yoon-Nelson model, the adsorption data provided the best fit with the R2 value above 0.95. The time taken for the breakthrough is very similar to model prediction values. Experiments with real batik dye wastewater showed the immense potential of modified Mengkuang leaves where total removal of real Batik wastewater was instantaneous.

Wastewater Treatment for Heavy Metals and Dyes Using Low-Cost Biosorbents: A Review

The pollution of industrial wastewater with heavy metals and dyes is a highly important environmental problem, because of the propagation of the pollution and because of its unfavourable consequences. Sustainable wastewater treatment is one of the foremost challenges of this century. Various waste materials characterized by lignocellulose composition are low cost, non-conventional adsorbent for biosorptive removal of heavy metal ions from aqueous solutions. Recent studies point to the potential of use of low-cost materials (zeolites, carrot residue and green tea waste) as effective sorbents for the removal of Cd2+ from aqueous solution. The use of bentonite to the treatment of wastewater containing reactive dyes in aqueous solutions requires the modification of the hydrophilic surface by inorganic cations with organic cations exchange. The use of bentonite as an inexpensive sorbent for the removal of Remazol Brilliant Blue R (RBBR) from synthetic aqueous solutions has been also presented in recent studies. The influence of some parameters such as: pH, initial dye concentration, sorbent dose on sorption kinetics for dye removal has been reviewed in this paper.&#x0D;

Highly efficient and selective removal of anionic dyes from water using a cellulose nanofibril/chitosan sponge prepared by dehydrothermal treatment

To obtain cost-effective and environmentally friendly adsorbents that can selectively remove anionic dyes from wastewater, a physically cross-linked cellulose nanofibril/chitosan (CNF/CS) sponge was developed by dehydrothermal treatment (DHT). The physicochemical properties of the prepared sponge were determined by various techniques, and its adsorption performance was evaluated using reactive blue 221 (RB) as the model dye. Batch adsorption experiments reveal that the capacity of RB adsorption on the sponge increases up to 778.5 mg/g with increasing temperature. This value is greater than the maximum adsorption capacities of all other non-conventional adsorbents reported in the literature. Based on kinetic and thermodynamic assessments, the RB adsorption process is best described by pseudo-second-order kinetics and the Langmuir model, which suggests that it is actually an endothermic monolayer chemisorption process. The RB removal efficiency reaches 99.64% after five repeated continuous separations and the CNF/CS sponge can be efficiently used in five adsorption-desorption cycles. Overall, the results reported in this study indicate that the novel CNF/CS sponge developed in this study has great potential for use in applications of dye removal from wastewater.

Estudio de la adsorción de los colorantes “Drimaren Amarillo CL-2R” y “Basic Azul Marino 2 RN” en arcillas activadas

Las arcillas se han convertido en absorbentes no convencionales debido a su disponibilidad, bajo costo y alta eficacia de absorción de colorante. El objetivo de esta investigación fue estudiar la adsorción de un colorante catiónico "Drimaren Yellow CL-2R" y un colorante aniónico "Basic Navy Blue 2 RN" en tres depósitos naturales de arcilla en el Ecuador localizadas en Cochancay, Santa Clara y Shirahuan. Las arcillas se caracterizaron por espectroscopia de fluorescencia de rayos X y difracción de rayos X. La espectroscopia ultravioleta-visible permitió la cuantificación de los colorantes que quedaban en la solución. Se estudió el pH, el tiempo de contacto del absorbente con el adsorbente, la concentración inicial del colorante y los efectos de la cantidad de arcilla. La eficacia de las tres arcillas en remover el colorante catiónico fue de 95-99% y del colorante aniónico fue de 70%. El modelo isotérmico del Langmuir se ajusta al mecanismo de adsorción de los colorantes catiónicos (R2=0,998), y a los aniónicos (R2=0.977). La arcilla de Shirahuan muestra la mayor capacidad de adsorción de colorantes catiónicos (27.53 mg/g). La arcilla de Cochancay muestra la mayor capacidad de adsorción de colorantes aniónicos (5.81 mg/g). La cinética de adsorción de los colorantes sigue el modelo de "pseudo-segundo orden" para ambos colorantes y sugiere que la tasa de adsorción es proporcional al cuadrado de los sitios de adsorción disponibles. Las arcillas activadas muestran una capacidad de adsorción seis veces mayor eliminando el colorante catiónico que el colorante aniónico de las muestras de agua sintética.

A renewable, sustainable and low-cost adsorbent for ibuprofen removal.

Adsorption efficiency of acid-modified kola nut husk (KNHA) as a non-conventional adsorbent for the sorption of Ibuprofen from aqueous media was investigated in this study. The raw and modified samples were characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, electron dispersive X-ray spectroscopy pH, and Boehm titration techniques respectively. Adsorption parameters such as pH effect, adsorbate concentration, contact time, and solution temperature were studied. The amount of Ibuprofen uptake was observed to increase with a corresponding increase in adsorption operational parameters. The kinetic data was found to best fit the pseudo-second-order kinetic model. Isotherm adsorption models of Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich were utilized to analyze the adsorption data. The Langmuir isotherm model showed the best fit for experimental data with a maximum monolayer adsorption capacity of 39.22 mg/g. The values of Gibbs free energy change were negative (-164.48 to -64.045.4 kJ/mol) suggesting that the process of ibuprofen adsorption onto KNHA was spontaneous. The positive value of standard enthalpy change (+34.203 kJ/mol) suggests that the process of ibuprofen adsorption was endothermic. KNHA adsorbent was found to be efficient and viable for the uptake of ibuprofen from aqueous medium. Hence, adsorbent prepared from kola nut husk waste has proved to be effective for the adsorptive uptake of Ibuprofen from aqueous media.

Adsorptive Removal of Dyes onto Cost Effective Biomaterials – A Review

A higher percentage of dyes from the industrial waste water are being released into aquatic ecosystems and polluted the natural ecosystem. An abundance of technologies available for removal of Dyes from the industrial waste water are expensive and ineffective. Many of these processes are economically not viable for small and medium scale industries due to large scale applications.Recent Investigational researches have proved that the successful elimination of dyes is obtained using numerous economically available non-conventional adsorbents also. Several experimental investigations on adsorption provedthattremendous treatment for dye removal and can be obtained using cheaply available non-conventional adsorbent.This review is mainly focused to the systematic study on utilizing low cost absorbent of dye removal from the effluents discharged from the industries. The data on economically cheap adsorbents and its properties for removing dyes resulted from the recent literature survey are summarized. Therefore, this review provides the various methods to treat the wastewater using low-price natural sources of adsorption materials, non-viable biomaterials.

Mass transfer studies of Direct Orange 102 dye onto a non-conventional adsorbent

Activated carbon with surface area of 896 m2/g has been prepared from the wood of Thevetia Neriifolia Juss (TNJAC). The fitness of the prepared activated carbon is tested for its adsorption capability towards the textile dye direct orange 102 (DO102). On increasing the solution pH from 2 to 12, the percentage of DO102 adsorption increases from 41 to 75%. The adsorption kinetics is analyzed using pseudo-first order and pseudo-second order kinetic models. Pseudo-second order model is more appropriate to describe the adsorption kinetics with a correlation coefficient of 0.9311< r2< 0.9871. On analyzing the adsorption isotherm using Langmuir and Freundlich models, the adsorption of DO102 by TNJAC follows Langmuir type of isotherm with energetically homogeneous sorbent surface.

Human Immunoglobulin G Adsorption in Epoxy Chitosan/Alginate Adsorbents: Evaluation of Isotherms by Artificial Neural Networks

Abstract This work aimed to evaluate the interaction of human IgG in non-conventional adsorbents based on chitosan and alginate in the absence and presence of Reactive Green, Reactive Blue and Cibacron Blue immobilized as ligands. The adsorption was evaluated at 277, 288, 298 and 310 K using sodium phosphate buffer, pH 7.6, at 25 mmol L−1. The highest adsorption capacity was observed in the experiments performed with no immobilized dye, although all showed adsorption capacity higher than 120 mg g−1. Data modeling was done using Langmuir, Langmuir-Freundlich and Temkin classical nonlinear models, and artificial neural networks (ANN) for comparison. According to the parameters obtained, a possible adsorption in multilayers was observed due to protein-adsorbent and protein-protein interactions, concluding that IgG adsorption process is favorable and spontaneous. Using an ANN structure with 3 hidden neurons (single hidden layer), the MSE (RMSE) for training, test and validation were 13.698 (3.701), 11.206 (3.347) and 7.632 (2.763), respectively, achieving correlation coefficients of 0.999 in all steps. ANN modeling proved to be effective in predicting the adsorption isotherms in addition to overcoming the difficulties caused by experimental errors and/or arising from adsorption phenomenology.

Simultaneous removal of Cd, Co, Cu, Mn, Ni, and Zn from synthetic solutions on a hemp‐based felt. III. Real discharge waters

ABSTRACTTwo hemp‐based materials were used as nonconventional adsorbents for the final treatment of industrial discharge waters (DWs) from a metal‐finishing plant. The first adsorbent, referred as HEMP, was a felt made of 100% hemp fiber. The second was the same felt coated with a maltodextrin‐1,2,3,4‐butanetetracarboxylic crosslinked polymer (HEMPM) in order to provide ion‐exchange properties to the material by introducing carboxylic groups. The batch experiments showed that both materials exhibited high adsorption capacities toward metal ions present in 12 DWs, leading to concentrations well below those allowed by the French regulation. Measurements of the germination rate of Lactuca sativa seeds and of mobility inhibition of Daphnia magna, used as ecotoxicological tests, were carried out on DWs before and after hemp treatment. The average germination rate before and after treatment were 47.2 ± 4.1 for untreated DWs, 71.2 ± 6.3 for DWs treated by HEMP, and 89.3 ± 4.7 for DWs treated by HEMPM. The EC50 values for four DWs were between 2.1 and 10.4% of DW, indicating high toxicity. After HEMPM treatment, exposure to the DW for 24 h did not cause immobilization (EC50 &gt; 90%). © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48823.

Adsorptive removal of chromium(VI) from aqueous solution unto groundnut shell

Chromium present in high levels in water poses a serious problem in many places around the world, sometimes in relation to natural sources and in other cases to anthropogenic ones. Adsorption process using natural materials is among the most effective techniques for removing many heavy metal ions from different types of water sources. In the present study, groundnut shell was used as a nonconventional adsorbent for effective removal of chromium(VI) from aqueous solutions using batch experiments. The adsorption of chromium(VI) unto groundnut shells was found to be dependent on contact time, pH, adsorbent dose, initial concentration and temperature. The adsorption of Cr(VI) was found to be optimum at a contact time of 120 min, pH 8.0, an adsorbent dose of 2.0 g/L, initial metal ion concentration of 25 mg/L and temperature of 41.5 °C. The experimental data were analyzed using three two-parameter isotherm models. The experimental data obtained for the adsorption of chromium(VI) ion fitted well to Temkin isotherm in comparison with the other isotherm models tested.

Removal of Sulfamethoxazole, Sulfapyridine and Carbamazepine, from Simulated Wastewater Using Conventional and Nonconventional Adsorbents

The use of phosphate rock (PR), porcelanite (PC) and granite (GR) as natural locally abundant adsorbents compared with adsorption by granular activated carbon (GAC) for removing pharmaceuticals including sulfamethoxazole (SMX), sulfapyridine (SP) and carbamazepine (CBZ) from simulated wastewater was examined. The removal efficiency of the three pharmaceuticals was found to follow the consequences as: PC ˃ GAC ˃ PR ˃ GR. The uptake efficiency of sulfamethoxazole was 91.51, 86.69, 69.51 and 53.97% onto PC, GAC, PR and GR, respectively, at initial concentration, pH, dosage and temperature of 50 mg/L, 4, 0.5 g/100 mL and 30 °C, respectively. The removal efficiency of sulfapyridine was 84.71, 81.97, 63.25 and 49.71%, respectively. However, for carbamazepine it was 80.46, 79.61, 54.10 and 43.44%, respectively. Fourier transform Infrared (FTIR) was carried out for PC before and after adsorption to determine the type of functional groups. Carbonyl and hydroxyl functional groups on the surface of PC were the major groups responsible for adsorption process. The effect of pH (5, 7 and 9), agitation speed (50–300 rpm), dosage (0.1–1.4 g/100 mL), contact time (30–360 min), temperature (10–60 °C) and initial concentration (25–100 mg/L) are studied to find out the optimum conditions for removing the selected pharmaceuticals using PC. Adsorption isotherms and kinetic models had been used to fit the experimental data. From which Langmuir and pseudo-second order models were found to be more represented to the experiments with high correlation coefficient for the three pharmaceuticals.