Low-cost Natural Adsorbent Research Articles

Recent Advances on the Adsorption of Pollutants from Aqueous Media Using Clay-Based Adsorbents

The sequestration of pollutants from wastewater remains an active research topic recently owing to persistent disposal of industrial wastewater to waterbodies without adequate management strategies available especially in the developing countries. Different technologies have been employed in which adsorption has found a wide range of application. Today, various low cost adsorbents have been developed and evaluated for the adsorption processes. Clay mineral is one of the low cost natural adsorbents requiring minimum modification to enhance its adsorptive capacities. To maintain a clean and safe environment the water bodies must be free of contaminants of emerging concern. The availability of potable water is a global effort, as two of the UN's seventeen Sustainable Development Goals (SDG) are centered on water which is not surprising. Goal 6 focuses on clean water and sanitation whereas Goal 14 focuses on life below the water. With this in view, the availability of potable water highlights the significance of this study, which analyzes the potential of clay minerals as a good precursor for water treatment. Therefore, this review focuses on the clay minerals, its availability in Nigeria, classification and modification of the clay adsorbent.

Development of low-cost natural adsorbent for the abatement of pollution from tannery effluent – A green technology

Tanneries are known to be one of the most polluting industries due to the generation of harmful contaminants at various stages, from the beam house to finishing. Each day, significant quantities of tannery wastewater containing contaminants like chromium salts are released into open areas, farmlands, rivers and other corpses of water. This practice poses a severe threat to the environment health, leading to extensive soil and water pollution. In this study, a biological material (scales of fish Catla catla) is employed as an adsorbent for biosorption of contaminants from tannery effluent. Every day a considerable amount of fish scales is generated and thrown away from the local fish market, which burdens the environment and causes environmental pollution. The primary emphasis of this study is to reduce wastewater pollution and the environmental burden of fish waste disposal. Two adsorbents were prepared by treating the dried fish scales with NaOH and Orthophosphoric acid to enhance the adsorbent properties by creating pores and roughness of the surface. Then, it was characterized using FTIR, SEM, and TGA analyses. After characterization, adsorbents were subjected to the adsorption of a standard chromium solution to detect the ideal adsorbent dose, contact time, and pH conditions of adsorption. The study's findings showed that during adsorption, the maximum uptake capacity of acid-treated adsorbent is found at pH 4 with an adsorbent dose of 20 g/L for a 60-minute contact time. That base-treated adsorbent is obtained at pH 2.50 with an adsorbent amount of 20 g/L for 4 hours of contact time. Then, the adsorbents were used to treat tannery effluents, and it was discovered that they successfully removed pollutants like chromic oxide, total suspended solids (TSD), total dissolved solids (TDS), BOD, COD, and others. The results indicated that the acid-treated adsorbent achieved optimal removal percentages for chromic oxide, BOD5, COD, TDS, and TSS at 72.82%, 42.85%, 56.12%, 13.37%, and 35%, respectively. Thus, the study concluded that acid and base-washed fish scale adsorbents are affordable and straightforward to use adsorbents for removing pollutants from tannery effluent.

Crystal Violet Removal from Aqueous Solution Using Urtica Dioica Leaves Powder as A Low-Cost Natural Adsorbent: Isotherm, Kinetics and Thermodynamics Studies

Crystal Violet Removal from Aqueous Solution Using Urtica Dioica Leaves Powder as A Low-Cost Natural Adsorbent: Isotherm, Kinetics and Thermodynamics Studies

Determination and eco-friendly suppression of fluoride contamination in ground water samples using activated carbon constituents of carica papaya – A natural adsorbent

A significant contribution to increasing water supply comes from ground water and thereby meets the ever increasing demands for almost 90% of the Indian population. Problems are being faced due to the presence of excess fluoride, arsenic and nitrate in groundwater. It is also observed that low levels of fluoride in ground water can help prevent dental cavities, at the same time, higher levels of fluoride can induce dental fluorosis & skeletal fluorosis. Therefore, the fluoride level in ground water needs to be monitored and strictly controlled. Fluoride levels in drinking water should not be more than 1.5 mg/l, as recommended by the WHO and the Bureau of Indian Standards. The ideal fluoride limit for drinking and cooking is 1 mg/l, while 1.5 mg/l is acceptable if there is no other source available. Therefore, the present study analysis the water samples taken from various bore holes (provided with the locations of water sample using a Global Positioning System (GPS)) for all possible parameters like hardness, alkalinity, pH, TDS, EC, chloride, sulphate and fluoride followed by the removal of fluoride contamination in ground water samples using adsorptive filtration technique with the help of a novel, low cost natural adsorbent (activated charcoal obtained from carica papaya leaves). This work aims to determine and suggest a low cost material (Activated carbon obtained from carica papaya leaves) as an effective natural adsorbent for the defluoridation of ground water using the natural adsorbents in experimental testing. In addition to this, a mobile app for providing the related information and a separate Geographical Information System (GIS) mapping are also done. From the adsorption study, a reduction of about 84% fluoride was achieved. The obtained results were compared with the previously reported results. It is found that the prepared activated charcoal from papaya leaves is highly efficient than previously reported methods. Therefore, for the suppression of fluoride content in ground water samples, an eco-friendly reduction method using papaya leaf charcoal is suggested.

Utilization of Agricultural Waste as Low-Cost Adsorbents in Dye Wastewater Treatment: Kinetic and Thermodynamic Study

In recent years, the treatment of dye wastewater has attracted more attention because of its harmful impact on the environment. Therefore, dye wastewater should be treated using effective treatment methods, such as adsorption, which is widely employed to remediate many dyes from wastewater. This work studied the use of Laurus Nobilis Leaves (LNL) and sawdust (SD) as low-cost natural adsorbents to remediate reactive blue (RB) dye from synthetic wastewater under the influence of their dosages (0.5-5.5 g) for each, pH (3-9), and contact time (10-190 min). The experimental design, analysis of results, and optimization were conducted using Response Surface Methodology (RSM) based on Box-Behnken method (BBM) and the Minitab-Statistical program. The BET and FT-IR tests have been used to characterize these adsorbents, which show that SD-adsorbent includes more pore volume and surface area than LNL-adsorbent. The adsorption isotherms study revealed that Langmuir isotherm was a more fitted model than Freundlich model. Adsorption kinetic shows that the current adsorption process obeys the pseudo-second order model (R2=0.998) compared to the pseudo-first order model (R2=0.973) and the intraparticle diffusion model (R2=0.915). Thermodynamics study revealed that the present adsorption is endothermic, random irregularity at the solid-liquid, and a spontaneous nature. More than 60% of RB-dye removal efficiency was achieved at the optimal conditions, which were 5.5 g of SD-adsorbent, 0.8 g of LNL-adsorbent, pH 3, and 141 min of the contact time. The core results proved that the interaction effect of using multi-natural adsorbents was significant and cost-effective, providing considerable removal of dye from wastewater.

STUDY OF KINETIC, ISOTHERMAL, AND SORPTION CHARACTERISTICS OF SOME DYES USING NOVEL LUPINE PEEL POWDER

Synthetic dyes are considered harmful compounds to the environment even in slight quantities. Low-cost natural adsorbents have been proven helpful for water treatment. In the current research, Lupine peel was used in inactivated (IL) and activated (AL) forms to remove Basic Fuchsin (BF) and Eosin (E) dyes from aqueous media. Adsorbents have been evaluated by FTIR and SEM. The operational settings, including the solutions pH, adsorbent dosage & size, initial dye concentration, temperature & contact time were all controlled in a batch system. According to experimental outcomes, the adsorption procedure occurs quickly & naturally. A pseudo-2nd-order kinetic model gives the best fit to the experimental information of BF & E dyes adsorption onto IL and AL. Adsorption isotherm data of BF adsorption was fitted well to the Freundlich model, while E adsorption was well fitted to the Langmuir adsorption isotherm. Optimal adsorption capacities of 1.5344, 2.9913, 0.7983, and 1.0921 mg/g for BF and E adsorption onto IL and AL respectively. According to the (D-R) isotherm model, the values of E were 0.5, 2.357, 0.05, and 0.0707 KJ/mol for BF and E onto IL and AL respectively, indicating a physisorption process. The activation parameters (∆Go, ∆Ho, ∆So) were calculated. The adsorption was endothermic and spontaneous with a higher preference of BF than E onto AL and IL. The findings indicate that the lupine peel has the potential to function as a low-cost adsorbent for the elimination of BF & E dyes from aqueous solutions.

Cd+2 SORPTION FROM AQUEOUS SOLUTION USING ROSEMARY PLANT: PERFORMANCE AND ISOTHERM STUDY

This research was conducted to verify the removal efficiency of cadmium ions from an aqueous solution using a low-cost natural adsorbent. Rosemary plant was used in a batch system, and to understand this process more, several factors were investigated as follows: pH, contact time, initial metal ions concentration, amount of adsorbent material, and agitation speed. All experiments were carried out at room temperature. Whereas, the results showed the optimal value of removal was 83% for cadmium onto rosemary plant, under optimum operating conditions: pH 5, the adsorbent material dosage 2 g/100 ml, contact time 60 min, the metal concentration 10 mg/L, and agitation speed 250 rpm. The Freundlich adsorption isotherm model fits the equilibrium adsorption data for Cd+2better than the Langmuir model. This study found that the rosemary plant as a cost-effective and locally adsorbent for removing Cd+2from polluted water is efficient. Thus, it is possible to use the rosemary plant as a low-cost material to be used to adsorb heavy metals from wastewater.

Adsorption technique for the removal of heavy metals from wastewater using low-cost natural adsorbent

The primary goal of this study was to use low-cost adsorbents, this achieves by using pine cones as plant waste adsorbents in the treatment of industrial wastewater. In the experimental work of this study, a system of PVC horizontal pipes of 15cm diameter and 600 cm length without membranes was used. The polluted water values discharged in the system were 20, 40, 60, 80, and 100 L/hr. The effect of many hydraulic parameters (contact time, flow discharge, length of the pipe, and pressure) with environmental parameters (pH, TDS, TSS and electrical conductivity) was investigated in this continuous flow system. The sample of plant waste (pine cone) was treated and activated by ozonation, to manufacture new media with high porosity, activated carbon developed from pine cone (ACPC), and to determine the activity that produces the best results in the removal of heavy metals. To remove Fe+2 and Zn+2 ions from industrial wastewater, activated carbon was used as an adsorbent. Adsorption tests result in an exhibit that, the ACPC adsorbent had remarkable heavy metals removal efficiency. The most effective removal efficiency of 95% of Zn+2 was recorded at pH 7, 20 l/hr, and 5hrs. The higher removal efficiency of 96.67% of Fe+2 occurred at pH 6, 20 l/hr, and 5hr. The study also revealed that activated carbon devolved from pine cones can be adopted as a low-cost alternative for removing metal ions.

A review of biomaterial as an adsorbent: From the bibliometric literature review, the definition of dyes and adsorbent, the adsorption phenomena and isotherm models, factors affecting the adsorption process, to the use of typha species waste as adsorbent

This paper presents a review of adsorption isotherms of some dyes from aqueous solutions by biomaterial. In this paper, we reported Typha waste as a model of biomaterial classified as a low-cost adsorbent. The paper also briefly discusses about the literature information from the definition of dyes and adsorbents, bibliometric analysis, adsorption phenomena, adsorption isotherm models, and factors affecting the adsorption, to the use of Typha species waste as a low-cost adsorbent. The operational parameters factors are explained in terms of pH, adsorbent dosage, contact time, and initial dye concentration that will affect the process of removing textile dye. The solution of pH turns out to be the most important condition in the adsorption process for anionic dye, a low pH value are preferable in contrast to cationic dye where the suitable pH value is high. For the adsorbent dose, the adsorption capacity increase along with the increment of adsorbent dosage due to the increase of theavailable amount of adsorption site. The contact time between the adsorbent and dye affects the efficiency of dye removal where a strong attraction force will shorten the time. As for the effect of dye initial concentration, increasing the initial concentration enhances the increment of adsorbent surface area to adsorb dyes. Several isotherm models are described. The Langmuir model is frequently used to evaluate the adsorption capacity of the Typha species waste as adsorbents. This review paper suggested that the accuracy level obtained from adsorption processes is greatly dependent on the successful modeling of adsorption isotherms. Typha biomaterial wastes can be considered as the new useful low-cost natural adsorbents for dye clean-up operations in aquatic systems.

Ketoprofen and aspirin removal by laccase immobilized on date stones

In recent years, enzymatic remediation/biocatalysis has gained prominence for the bioremediation of recalcitrant chemicals. Laccase is one of the commonly investigated enzymes for bioremediation applications. There is a growing interest in immobilizing this enzyme onto adsorbents for achieving high pollutant removal through simultaneous adsorption and biodegradation. Due to the influence of the biomolecule-support interface on laccase activity and stability, it is crucial to functionalize the solid carrier prior to immobilization. Date stone (PDS), as an eco-friendly, low-cost, and effective natural adsorbent, was utilized as a carrier for laccase (fungus Trametes versicolor). After activating PDS through chemical treatments, the surface area increased by thirty-six-fold, and carbonyl groups became more prominent. Batch experiments were carried out for ketoprofen and aspirin biodegradation in aqueous solutions. After six cycles, the laccase maintained 54% of its original activity confirmed by oxidation tests of 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS). In addition, the storage, pH, and thermal stability of immobilized laccase on functionalized date stone (LFPDS) were found to be superior to that of free laccase, demonstrating its potential for ongoing applications. In the aqueous batch mode, this immobilized laccase system was used to degrade 25 mg L−1 of ketoprofen and aspirin, resulting in almost complete removal within 4 h of treatment. This study reveals that agricultural wastes such as date stone can successfully be valorized through simple activation techniques, and the final product can be used as an adsorbent and substrate for immobilization enzyme. The high efficiency of the LFPDS in removing ketoprofen and aspirin highlights the potential of this technology for removing pharmaceuticals and merits its continued development.

Assessment of the impact of diluted and pretreated olive mill wastewater on the treatment efficiency by infiltration-percolation using natural bio-adsorbents.

The current study was carried out to treat the olive mill wastewater (OMW) via infiltration percolation process, using low-cost natural adsorbents that could improve the ability of the system to enhance the disposal rate of elimination of pollutant from the OMW. The experimental pilot was composed of three PVC(polyvinyl chloride)columns with 10cm in diameter and 110-cm height equipped with lateral air entries. Each column was filled with four layers of 10cm of a mixture of sand (70%), charcoal (20%) and sawdust (10%) respectively. These layers were alternated by four permeable layers of 10cm of Pouzzolane. To assess the effect of the pretreatment on the efficiency of the system, three types of OMW were used: raw OMW, diluted OMW with domestic wastewater at 1/1(v/v) ratio and OMW pretreated with lime. For the column feed with raw OMW, an average removal of total COD (41%), dissolved COD (54%), NH4-N (40.25%), NO3- (15.76%), total phosphorus (55.63%) and orthophosphate (50.84%) was recorded. The results showed that the column feed with diluted OMW with domestic wastewater was the most efficient one with a removal rate that reached 93.2% of total COD, 86.2% of dissolved COD, 92% of polyphenol, 92% of orthophosphate (OP), 97.2% of total phosphorus (TP) and 81% of NH4-N. The pretreatment of OMW with lime gave the lowest removal rate for all the parameters: total COD (34%), dissolved COD (50%), NH4-N (30%), NO3- (- 21%), total phosphorus (15.19%) and orthophosphate (9.04%). This study demonstrated that the dilution is a way to optimize the efficiency of the system of infiltration-percolation in treating the OMW.

Pseudo-stem banana fiber as a potential low-cost adsorbent to remove methylene blue from synthetic wastewater

In this work, pseudo-stem banana (Musa acuminata) (PBF) fiber was utilized as a potential low-cost natural adsorbent to uptake methylene blue (MB) dye from synthetic wastewater by batch adsorption process. Different adsorption factors like contact time, pH, initial concentration, and adsorbent dosage were explored and found that the separation process is strongly pH dependent. Additionally, the adsorption data were fitted with various adsorption isotherms like Langmuir, Freundlich, Temkin, and Dubinin–Radhushkevich models to detect the adsorption equilibrium phenomena. Reaction kinetics was inspected using pseudo-first-order and second-order kinetic models. Mass transfer and intra-particle diffusion analyses indicate the adsorption mechanism of the system described particularly in the context. Furthermore, scanning electron spectroscopy (SEM) and Fourier transformed infrared spectroscopy (FTIR) were conducted to get the morphology and surface properties of the adsorbent, respectively. As a result, the as-prepared banana fiber can be proposed as a cheap suitable adsorbent to separate dyestuffs from industrial wastewater.

Removal of copper ions from alembic cachaça using agro-industrial residues as biosorbents

Cachaça is a typical Brazilian distilled beverage made from fermented sugarcane juice. The copper levels in alembic cachaça are of great concern among producers, and the removal of this contaminant is important for the quality of the product. The present study aimed to remove copper ions from alembic cachaça by adsorption. Sugarcane bagasse, okara, Moringa oleifera Lam., three different types of zeolites, and two types of commercial charcoal were tested as biosorbents. The heat-treated sugarcane bagasse removed 100% of the copper present in a cachaça sample, while other low-cost natural adsorbents had close to 50% removal as was observed for M. oleifera seeds and okara. All adsorbents had porous and fibrous structures, favorable to adsorption. A kinetic study showed that a pseudo-second-order model was appropriate, with equilibrium times of 15 h for heat-treated sugarcane bagasse, okara, and M. oleifera seeds used as adsorbents. The Langmuir model better fitted the experimental data, indicating monolayer adsorption. The maximum adsorption capacity was 17.00, 0.77, and 5.33 mg of Cu g−1 for the heat-treated sugarcane bagasse, M. oleifera seeds, and okara, respectively. The results presented here are promising indicating three agro-industrial residues were favorable to the adsorption of copper ions from alembic cachaça.

Performance of Treated and Untreated Spent Coffee Ground on the Removal of Cu (II) in Aqueous Solution: A Comparative Study

The performance of two types of spent coffee ground (SCG), (i) untreated spent coffee ground (USCG) and (ii) acid-treated spent coffee ground (TSCG) on the Cu (II) removal from aqueous solution was investigated and compared in this study. The effects of operating parameters such as pH, contact time and initial Cu (II) concentration on the adsorption rate were studied in batch adsorption mode. The USCG showed better results than the TSCG. The highest removal efficiency of Cu (II) (50 mg/L) by USCG was 91.03% with an adsorption capacity of 45.52 mg/g, which was achieved at pH 6 and 90 min of contact time. The TSCG showed lower performance with a removal efficiency of 44.18% and adsorption capacity of 37.06 mg/g. This may be due to the flushed off in the functional groups of SCG that used for metal binding in the adsorption during acid treatment and the existence of Cl- ions on the TSCG surface, interfering the Cu (II) adsorption and reduces its adsorption capacity. Freundlich fitted well with the equilibrium data for copper (II) removal, as indicated by the R2 coefficient, for USCG and TSCG were 0.9912 and 0.9622, respectively. These data indicate that both USCG and TSCG have high sorption capacity and affinity for metal ions. The USCG showed a better Cu (II) removal than the TSCG, indicating a promising function as a low-cost natural adsorbent for Cu (II) and also other heavy metals removals.

Enhanced melanoidin removal by amine-modified Phyllanthus emblica leaf powder

Melanoidins are classified as hazardous colouring and polluting biopolymers, which are generated in very large amounts in molasses-based distillery effluent. In this study, melanoidin was removed through adsorption using amine surface-modified Phyllanthus emblica leaf powder (PELP) as a low-cost natural adsorbent. The amine-modified adsorbents were prepared by forming self-assembled monolayers (SAMs). The pzc of melanoidin and anime-modified PELP were found to be 6.9 and 3.8, respectively. RSM-CCD was used to optimize the environmental conditions considering adsorbent doses (0.2–2 % w/v), pH (3–11) and temperature (25–55 °C). A complete decolourization of melanoidin (98.50 ± 1 %) was observed at the optimized conditions (44.0 °C, pH = 5.93 and dose = 1.34 % w/v) along with 93.4 ± 0.2 % of COD reduction. The surface modification enhanced the maximum adsorption capacity to 616.2 mg g−1 i.e. 2.5 folds. The modified adsorbent also resulted in colour removal and COD reduction as 91 ± 3 and 84 ± 2 %, respectively from a real spentwash sample.

One-step processing of low-cost and superb natural magnetic adsorbent: kinetics and thermodynamics investigation for dye removal from textile wastewater

A simple, one-step and dry hybridization technique was successfully implemented to fabricate superb and low-cost magnetic adsorbent for removal of organic dyes. The structural and textural properties of the prepared banded iron formation @bentonite (BIF@BEN) composite were clearly investigated using X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectrometer (EDS), Brunauer–Emmett–Teller surface area (BET) and porosity analysis (BJH) techniques. The dye removal efficiency was optimized by studying several parameters, namely, pH, temperature, contact time and initial dye concentration. The maximum adsorption capacity achieved for crystal violet (CV) and acid red (AR) dyes were about 117 and 91 mg/g, respectively at pH 7, 60 °C in 60 min. The equilibrium data of both dyes’ adsorption on the BIF@BEN composite showed better fitting to Langmuir isotherm. The thermodynamic studies revealed that the adsorption process is spontaneous, endothermic and favorable at high temperatures. The prepared magnetic adsorbent showed higher adsorption performance than activated bentonite for removal of anionic dye (AR) and the same performance for removal of cationic dye (CV). The magnetic adsorbent is actually reused and easily separated from textile wastewater with total removal efficiencies 81% and 74.5% for all inorganic and organic pollutants, respectively after two adsorption cycles.

Chitosan-nickel oxide composite as an efficient adsorbent for removal of Congo red from aqueous solution

The chitosan-nickel oxide (CS-NiO) composite was synthesized and characterized by XRD, FT-IR, SEM, TEM, BET, and TG-DTG. The as-prepared composite was used as an adsorbent for the removal of Congo red (CR) dye from aqueous solution. Effects of various parameters such as solution pH, adsorbent dosage, initial dye concentration, contact time, and temperature on the adsorption of CR were investigated. The adsorption kinetics was found to conform to the pseudo-second-order kinetics model with good correlation. The adsorption of CR on the CS-NiO composite followed the Langmuir model and the maximum adsorption capacity at 25 °C determined from Langmuir model was 188.68 mg/g. The thermodynamic data revealed the spontaneous and endothermic nature of the adsorption process. The CS-NiO composite adsorbent can be separated from system effectively and easily, and maintained high adsorption efficiency even after five-time recycles. The aforementioned results demonstrated that the CS-NiO composite could be used as an efficient and low-cost natural adsorbent for the removal of CR from aqueous solution.

Design and cost analysis of batch adsorber systems for removal of dyes from contaminated groundwater using natural low-cost adsorbents

Batch adsorbers were designed for the adsorption of the fabric dyes Basic Violet 16 (BV16) and Reactive Red 195 (RR195) on locally available low-cost natural adsorbents of Persian bentonite, vermicompost and Persian charred dolomite. The adsorption isotherm data were in agreement with the Langmuir isotherm model (R2 > 99%). Results showed that with increasing the adsorption capacity of bentonite for BV16 from 434.78 to 833.33 mg/g due to the presence of the anionic dye, the amount of the adsorbent decreases by 50%. The adsorption capacity of vermicompost for the cationic dye was obtained 16 mg/g in single dye solution and of charred dolomite for the anionic dye was almost 7 mg/g in both dye systems. Based on the extended Langmuir model, the maximum adsorption capacity of natural bentonite for BV16 and of charred dolomite for RR195 were concluded 821.63 mg/g and 7.03 mg/g, respectively, which the capacities are almost the same in single and binary systems. The adsorption capacity and removal efficiency of Persian bentonite from contaminated water are comparable with that of activated carbon. Compared to activated carbon bentonite and the other natural adsorbents used in this study are less expensive and do not require a separate activation or pre-treatment step. Cost for 90% removal of dye from 100 m3 groundwater using 1 kg the studied adsorbents of vermicompost, charred dolomite and bentonite was calculated 0.06, 0.05 and 0.04 euro, respectively, in both single and binary systems.

Biosorption of Methylene Blue Dye from Aqueous Solutions

Synthetic dyes, like methylene blue, in effluents of chemical industries, are reported to be toxic with alleged carcinogenic and genotoxic consequences. Biosorption is considered as a low-cost alternative to the costly removal processes. Agricultural wastes and plant biomass and are contemplated to be low-cost candidates because they can be used without or with a minimum of processing. This work was intended to test the possibility and comparative study of different low-cost natural adsorbents [Coconut husk (H), Groundnut shell (G), Cow Dung (C) and moss (M)] for the sequestration of methylene blue dye from aqueous solution. A batch process was done to study the effects of different parameters such as contact time, pH, adsorbent dosage and initial dye concentration. Adsorption equilibrium data were represented using Langmuir, Freundlich and Temkin isotherm models. 75 % of dye removal was observed with moss, hence proves to be an effective, low-cost adsorbent.

Potential Use of Alkaline-Activated Indonesian Pumice Powder as Lead Adsorbent in Solution System

<p>Pumice is a volcanic material that found abundant in Indonesia. Owing to its physicochemical characteristics it can be utilized as a low-cost natural adsorbent for cationic contaminants. This study aimed to assess the performances of adsorbents prepared from NaOH-activated powder of Lombok and Kediri pumices for lead removal in solution systems based on their maximum adsorption capacity and removal efficiency parameters. The adsorption tests were done in batch experimentation using pumice powder of 74 μm particle size activated with 0.5, 1, and 2 <em>M</em> NaOH and lead solutions with initial concentrations of 0-260 mg.L<sup>-1</sup>. The most favorable NaOH activation concentration for both pumices was 0.5 <em>M </em>which resulted from Lombok pumice prepared-adsorbent with Pb maximum adsorption capacity based on linearized conventional and rearranged Langmuir isothermal adsorption models of 236.4 and 186.3 mg.g<sup>-1</sup>, while those of Kediri pumice were of 218.4 and 210.8 mg.g<sup>-1</sup>, respectively. The removal efficiency of both adsorbents were >80% at the initial Pb concentration of <100 mg.L<sup>-1 </sup>and around 50-80% at 100-260 mg.L<sup>-1</sup>. Both pumices are therefore considered potential to be utilized as an adsorbent for cationic contaminants in solution systems with reliable performances.</p>