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In recent years, developing economical adsorbents to treat with different types of pollutants has attracted great interest. Waste mussel shells are common wastes produced by the seafood industry. They have some advantages over conventional process such as simplicity of design and low cost. In this study, the uncalcinated and calcinated mussel shells were characterisated for their surface characteristics. Mussel shells washed with tap water several times followed by distilled water and dried at 105°C for 12 hours in an oven. They were powdered to small particles and calcined at 900°C for 2 hours. The sample was finely ground into small particles of different sizes, washed with distilled water and dried overnight at 105°C. And then, the sample was calcined at a heating rate of 2°C/min to 400°C and maintaned at this temperature for 4 hours.The calcined and uncalcined mussel shell samples were characterised by Fourier transformed infrared spectroscopy, scanning electron microscopy equipped with an energy dispersive spectrometer, Brunauer–Emmett–Teller and Zeta potential mesaurements. The results indicated that calcination studies improved the surface charasteristics of the mussel shells and that the calcinated mussel shells can be used in adsorption studies as a novel low-cost, eco-friendly biosorbent efficiently Keywords: Adsorption, calcination, characterization, mussel shell.

"Fabrication of superhydrophobic surfaces on aluminum substrates by dip coating method" isimli bu posterin özet bilgisi bulunmamaktadır.

Ionic liquids have many interesting properties such as low vapor pressure, wide liquid range, non-volatility, ionic conductivity, and high thermal stability. Even though these properties make ionic liquids a good alternative in various technological devices; problems such as leakage and portability limits the the use of ionic liquids. In recent years, ionogels have gained significant value by overcoming the liquid form problems and by preserving the basic properties of ionic liquids. In this study, imidazolium based ionic liquid was changed to ionogel by using a silica source such as tetraethylorthosilicate (TEOS), tetramethylortosilicate (TMOS) and methyltrimethoxysilane (MTMS), and formic acid was used as both solvent and catalyst. The effects of different silica sources, molar ratios of components, gelling and aging time on ionogel formation were investigated by experimental studies. Synthesized ionogels were characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), Raman Spectroscopy and Ultraviolet-Visible (UV-Vis) Spectroscopy analyzes. The stable ionogels were obtained with 1: 8 silica: formic acid molar ratio, 96 hours of gelation time and 8 days of aging time. It has been determined that the synthesized ionogels have smooth and transparent structure.

Water repellency and self-cleaning properties are the most important characteristics for outdoor environment. The water contact angle (CA) of a surface is lower than 90◦, the surface is described as a hydrophilic surface. In addition, a surface is higher than 90◦, the surface is described as a hydrophobic surface. In superhydrophobic surfaces, CA is upper than 150 ͦ and the sliding angle (SA) is lower than 10 ͦ. They have attracted growing research attention, due to their important practical applications. In principle, superhydrophobic surfaces can be obtained by roughness of surface and reduction of surface tension. In this study, aluminum plates (5 cm x 2 cm x 1 cm) were polished with sandpaper. Then the plates were cleaned by sonication in acetone and ethanol. Afterwards, the cleaned aluminum surfaces were chemically etched by phosphoric acid (H3PO4) at different concentrations. Surface modification was done by dodecyltriethoxysilane at different concentrations and times. All these experiments were performed under atmospheric conditions. Finally coated samples were cured at 100 ͦC for 1 h. The morphology of the synthesized surfaces was characterized by scanning electron microscopy (SEM-EDX). The superhydrophobicity of the surfaces was determined by CA measurements. The best superhydrophobicity was obtained by acid etching method with %3 H3PO4 concentration and modification by 0,01 M dodecyltriethoxysilane for 1 h. As a result of CA measurements, maximum 156,83 ͦ value was obtained for coated aluminium surfaces. SEM image showed that the etched aluminum surface.

In this study, chitosan (C)/marble powder (M) composites were used as an adsorbent for the removal of Dimozol Red Dye from aqueous solution. Chitosan (C)/marble powder (M) composites with different weight ratio percentage (C100M0, C70M30, C50M50 and C30M70) were prepared with marble powder and chitosan. Batch studies were carried out to address various experimental parameters such as contact time (0-72 hours), pH (3-11), adsorbent dosage (0.2-2.0 g/L) and initial dye concentration (40-100 mg/L). Equilibrium isotherms were analyzed by Langmuir, Freundlich, Temkin and Dublin-Radushkevich isotherm equations using correlation cooefficients and the results were best represented by Freundlich isotherm model. And also, adsorption kinetic was performed using the pseudo-first-order, the pseudo-second-order and intra-particle diffusion kinetic models. The adsorption kinetics well fitted with a pseudosecond-order kinetic model.

Anadolu Üniversitesi ve Bilecik Şeyh Edebali Üniversitesi tarafından ortak yürütülen program. Tez çalışması kapsamında malonamit ile fonksiyonelleştirilmiş bir iyonik sıvı ([MAL][NTf2]) sentezlendi. İyonik sıvının sentezi dört aşamada gerçekleştirildi ve yapısı NMR, FTIR ve HRMS analizleri ile aydınlatıldı. Çalışmaların ilk kısmında, sentezlenen iyonik sıvı kullanılarak Nd, Dy, Eu, La, Lu, Y ve Yb NTE'lerinin, Ba, Mg, Al, Fe, Ni ve Co metallerinin, yeşil, mavi ve kırmızı fosforların ve Nd/Dy ve Eu/Zn karışımlarının asidik ortamda sıvı - sıvı ekstraksiyonları gerçekleştirildi. Ekstraksiyon çalışmaları pH'a bağlı olarak sürdürüldü ve metal konsantrasyonları ICP analizi ile belirlendi. Daha sonra sentezlenen iyonik sıvıya katı bir form kazandırmak amacıyla; iyonik sıvı bir silika kaynağı (TMOS, TEOS, MTMS) ve hem çözücü hem de katalizör olarak kullanılan formik asit ile iyonojel haline getirildi. İyonojel oluşumu için silika kaynağı cinsi, bileşenlerin molar oranları, jelleşme zamanı ve yaşlandırma zamanı gibi sistem parametreleri incelendi. İyonojeller BET, SEM, TEM, FTIR, Raman, TGA, XRD, UV-Vis, CHN-S analizleri ve sertlik testi ile karakterize edildi. Son olarak, elde edilen iyonojellerin endüstriyel olarak büyük öneme sahip Eu/Zn karışımlarının ayrımında membran olarak kullanılabilirliği test edildi. Membran sistem çalışmalarında kullanılmak üzere bir cam difüzyon hücresi tasarlandı ve ayrımın gerçekleşebilmesi için sistem parametreleri çalışıldı. Elde edilen sonuçlara göre; malonamit ile fonksiyonelleştirilmiş iyonik sıvının La(III), Dy(III), Yb(III) ve Lu(III) ayrımında sırasıyla % 71, % 92, % 79 ve % 88 oranında yüksek ekstraksiyon yüzdeleri verdiği ve nadir toprak elementleri için seçicilik gösterdiği belirlendi. Kararlı iyonojeller TEOS: formik asit molar oranı 1 : 8, jelleşme zamanı 96 saat ve yaşlandırma zamanı 8 gün için elde edildi. Sentezlenen iyonojellerin geniş yüzey alanı, gözenekli yapı, termal kararlılık ve amorf yapı gösterdiği belirlendi. Membran sistem çalışmalarında besleme fazı olarak 1 M HCl içinde bulunan Eu/Zn karışımı için alıcı faz olarak 0,1 M Na2CO3 kullanıldığında, % 24 oranında Zn(II)'nin alıcı faza geçerek Eu(III)'ten ayrılabildiği tespit edildi. Günümüzde birçok farklı alanda yaygın bir şekilde kullanılan NTE'lerin ayrımında, sentezlenen iyonik sıvı ve geliştirilen iyonojellerin kullanılabilirliği yeşil kimya alanında oldukça önemli ve umut vericidir. In the study, a malonamide functionalized ionic liquid ([MAL][NTf2]) was synthesized. The synthesis of ionic liquid was carried out in four steps and the structure was evaluated by NMR, FTIR and HRMS analyzes. In the first part of the study, solvent extractions of Nd, Dy, Eu, La, Lu, Y and Yb rare earth elements, Ba, Mg, Al, Fe, Ni and Co metals, green, blue and red phosphors and Nd / Dy and Eu/Zn mixture were carried out using the synthesized ionic liquid in an acidic medium. The extraction studies were followed depending on pH. The metal concentrations were determined by ICP analysis. Then, in order to give a solid form to the synthesized ionic liquid; the ionogel was synthesized with a silica source (TMOS, TEOS, MTMS) and formic acid used as both a solvent and a catalyst. System parameters such as silica source type, molar ratios of components, gelling time and aging time were investigated for ionogel formation. Ionogels were characterized by BET, SEM, TEM, FTIR, Raman, TGA, XRD, UV-Vis, CHN-S analyses and hardness test. The obtained ionogels were tested for their applicability as a membrane in the separation of industrially important Eu / Zn mixtures. A glass diffusion cell was designed as a membrane system and system parameters were studied to enable the separation. According to the results; [MAL][NTf2] gave high extraction percentages of 71%, 92%, 79% and 88%, respectively, for La(III), Dy(III), Yb(III) and Lu(III), and showed selectivity for rare earth elements. Ionogels were obtained with the TEOS: formic acid molar ratio of 1 : 8, gelation time of 96 hours and aging time of 8 days. The ionogels synthesized in this way presented high surface area, porous structure, thermal stability and amorphous structure. In the membrane system studies, 24% Zn(II) was transferred to the receiving phase and seperated from Eu(III) by using Eu/Zn mixture in 1 M HCl as feed phase and 0.1 M Na2CO3 as receiving phase. Nowadays, on the separation of rare earth elements widely used in many different fields, the use of synthesized ionic liquid and developed ionogels is very important and promising for green chemistry.

In the present study, chitosan (C)/marble powder (M) composites with different weight ratio percentage (C100M0, C70M30, C50M50 and C30M70) were prepared with marble powder and chitosan and characterized by Scanning Electron Microscopy (SEM). The composites were used for the adsorption of Dimozol Red dye from aqueous solutions. The influence of contact time, pH, adsorbent dosage, initial dye concentration and temperature on Dimozol Red adsorption onto the composites was investigated. Equilibrium data were analyzed by model equations such as Langmuir and Freundlich isotherms and were best represented by Freundlich isotherm model. Kinetic adsorption data were analyzed using the pseudo-first-order kinetic model and the pseudo-second-order kinetic model. The adsorption kinetics well fitted with a pseudo-second-order kinetic model. Thermodynamic parameters, ΔG°, ΔH° and ΔS°, were calculated, indicating that the adsorption of Dimozol Red onto the composites was spontaneous and exothermic in nature.

The conlacl tiıne betweeıı Lhe pollutanl ancl the ,rclsorbenı is or signifıcant importance in the \•vasıewater treatınent by adsorption. A rapid uptake of polluıants and establishınent or equilibriuın in a short period signifies tlıe efficacy of ıhat adsorhent for its use in wastewater treatment. in this study. the adsorplion characıeristics of Reacıive Blue 221 (RB22 I) from aqueous solution oııto chiıosan parıiclcs crosslinked with glutaraldehyde lıavc hccıı iıı\'cstigatcc.l. Thc clkct oı· coııtacl tiıııc lcıı- thc adsmptioıı ur 1{13221 by tlıc clıiıos;ııı parıiclc ,,as sıııdicd ror a rcrind of 72 lı li.ır iııitial d) l' nıııccııtr;.ıtioııs or 60 nıg/1 m 2.5"C. /\dsorb,rnı dosagc ıHıs 0.1 gi50 nıl ol" dvc solution at pi 1 6. The adsorption capacities of the synthesized chitosaıı was 27.36 mg/g for dye RB22 I. Kinetics of adsorptioıı was deternıined by aııalyzing adsorptive uptake of the dye froın aqueous solution at different tiıne intervnls. in order ıo investigate the adsorption processes of RB'.221 on the chitosan particles. lour kinelic nıodcls were usecl. including pseudo-first­ordcr. pseuclo-second-order. l:3anghaın and iııtra-parıick cliffusion ınodcls. The pseudo­second-order kinetic ınodel provided the besı fit to the experiınental data for the adsorption of RB22 I textile dye. Ovcrnll. tlıis sıud) iııdicutcs tlıc clıitosaıı parıiclcs as an effrctİ\ c: adsorbcnr for thc reınoval of Rcnctivc 131uc 221 dye rroın Lhe aqueous solutioııs.

Yapılan çalışmada, adsorban olarak kullanmak amacıyla, kitosan ve hegzagonal bor nitrür (hBN) kullanılarak farklı bileşimlere sahip kompozitler sentezlenmiş ve bu kompozitler sulu çözeltilerden Reactive Blue 49 (RB 49) boyar maddesinin adsorpsiyonunda kullanılmıştır. Kompozitlerin bileşiminde bulunan kitosan ve hBN’ nin kütlece yüzde oranı olarak, kitosan/hegzagonal bor nitrür (k/hBN) için k/hBN:100/0, k/hBN:75/25 ve k/hBN:50/50 oranlarında kompozitler sentezlenmiştir. Taramalı elektron mikroskobu (SEM) ve Fourier dönüşümlü infrared spekroskopi (FTIR) analizleri ile kompozitler karakterize edilmiştir. Sentezlenen kompozitler ile gerçekleştirilen adsorpsiyon proseslerine ait pH, zaman, adsorban dozajı, boyar madde konsantrasyonu ve sıcaklık parametreleri çalışılmıştır. Elde edilen sonuçlara göre; en yüksek giderimlerin k/hBN:100/0 ve k/hBN:75/25 kompozitleri için pH 4’ te, k/hBN:50/50 kompoziti için ise pH 3’ te gerçekleştiği belirlenmiştir. Adsorpsiyon prosesleri 240 dakika boyunca takip edilmiştir. Kompozitlerin 0,3 g/L adsorban dozajında en yüksek adsorplama kapasitesine sahip olduğu belirlenmiştir. Adsorpsiyon prosesleri kinetik açıdan incelendiğinde, prosesler yalancı ikinci derece kinetik model ve partikül içi difüzyon modeli ile uyumluluk göstermiştir. Adsorpsiyon dengesi araştırmalarında, prosesler Freundlich izoterm modeli ile açıklanmıştır. Termodinamik incelemelerde ise; adsorpsiyon proseslerinin endotermik olduğu ve kendiliğinden gerçekleştiği görülmüştür. Sonuç olarak; farklı bileşimlerde sentezlenen k/hBN kompozitlerinin sulu çözeltilerden RB 49 boyar maddesinin adsorpsiyonunda kullanılabileceği belirtilmiştir In this study, composites with different compositions were synthesized using chitosan and hexagonal boron nitride (hBN) to use as an adsorbent, and these composites were used in the adsorption of Reactive Blue 49 (RB 49) dye from aqueous solutions. Composites were synthesized for chitosan/hexagonal boron nitride (c/hBN) at the ratios of c/hBN:100/0, c/hBN:75/25 and c/hBN:50/50 as the percent by mass of chitosan and hBN in the composition of the composites. Composites were characterized with scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) analysis. The pH, time, adsorbent dosage, dye concentration and temperature parameters of the adsorption processes studied with the synthesized composites. According to the results; the highest removals were obtained at pH 4 for c/hBN:100/0 and c/hBN:75/25 composites, and at pH 3 for c/hBN:50/50 composite. Adsorption processes were followed for 240 minutes. It was determined that the composites had the highest adsorption capacity at 0.3 g/L adsorbent dosage. When the adsorption processes were examined in terms of kinetics, the processes showed compatibility with the pseudo second order and the intraparticle diffusion model. In adsorption equilibrium studies; the processes are explained by the Freundlich isotherm model. In thermodynamic studies; it has been determined that the adsorption processes are endothermic and occur spontaneously. As a result; it has been stated that c/hBN composites synthesized in different compositions can be used in the adsorption of RB 49 dye from aqueous solutions. Bilecik Şeyh Edebali Üniversitesi Bilimsel Araştırma Projesi - BAP - 2021-02.BŞEÜ.03-03. Bilecik Seyh Edebali Üniversity Scientific Research Project - BAP - 2021-02.BŞEÜ.03-03.

Yüzey kaplama işlemleri, malzemelere istenilen yüzey özelliklerinin kazandırılması için yoğun şekilde kullanılan ve geliştirilen bir konudur. Bu çalışmada, alüminyum yüzeyler üzerinde, daldırma kaplama yöntemi ile süperhidrofobik kaplamalar geliştirilmesi hedeflenmiş ve bu kapsamda deney koşulları deneysel tasarım yöntemlerinden biri olan Taguchi deney tasarım yöntemi ile de optimize edilmiştir. Deneysel tasarımda; zımpara, aşındırma ve modifikasyon olmak üzere 3 faktör belirlenmiş ve bu üç faktör için de 3 seviye belirlenerek, etki dereceleri ve birbirleri ile etkileşimleri incelenmiştir. Deneysel çalışmalarda numune olarak 7 cm x 2 cm x 1,5 mm boyutlarındaki alüminyum plakalar kullanılmıştır. Deney numunelerinin zımpara işleminde 3 farklı zımpara kağıdı (400,600 ve 800' lük) kullanılmıştır. Aşındırma ve modifikasyon işlemleri iki farklı deneysel çalışma ile gerçekleştirilmiştir. Her iki çalışmada da Minitab 18 programı kullanılarak L9 ortogonal düzende 9 farklı deney yapılmıştır. Birinci deneysel çalışmada; zımparalama işlemi tamamlanmış numuneler 4 M’ lık hidroklorik asit (HCl) çözeltisine 2, 4 ve 6 dakika daldırılarak aşındırılmıştır. Modifikasyon işlemi için, aşındırılmış yüzeyler 0,01 M derişiminde dodesiltrietoksisilanın etanollü çözeltisine 8, 16 ve 24 saat daldırılarak bekletilmiştir. İkinci seri deneysel çalışmalarda ise; ardışık olarak baz + asit muamelesi ile aşındırma işlemleri yapılmıştır. Burada, zımparalanmış numuneler 1 M sodyum hidroksit (NaOH) çözeltisine 10 dakika daldırılarak aşındırılmıştır. Ardından 20 ml H2O: 8 ml HCI: 1 ml CH3COOH oranındaki çözeltiye 3, 5 ve 10 dakika daldırılarak ikinci bir aşındırma işlemi yapılmıştır. Modifikasyon işleminde, aşındırılmış numunelere kütlece % 2’ lik palmitik asitin etanollü çözeltisi içinde 15, 30 ve 60 dk sürelerde daldırma işlemi uygulanmıştır. Elde edilen yüzeylerin süperhidrofobik özelliği, temas açı ölçüm cihazı ile belirlenmiş ve yüzey morfolojileri Taramalı Elektron Mikroskobu (SEM) ile incelenmiştir. Temas açı sonuçlarına göre; her iki çalışmada da 150°’ nin üzerinde temas açıları elde edilmiş ve alüminyum yüzeylere süperhidrofobik özellik kazandırıldığı belirlenmiştir. SEM görüntülerinde ise; süperhidrofobik yüzeylerin pürüzlü yapıda olduğu görülmüştür. Elde edilen sonuçlara göre; uygulanan yöntemin, alümünyum yüzeyler üzerinde süperhidrofobik kaplamaların geliştirilmesinde kullanılabileceği belirlenmiştir. Surface coating processes are a subject that is used and developed extensively to give the desired surface properties to the materials. In this study, it was aimed to develop superhydrophobic coatings on aluminum surfaces with the dip coating method, and the experimental conditions were also optimized with the Taguchi experimental design method, which is one of the experimental design methods. In experimental design; 3 factors were determined as sanding, etching and modification, and 3 levels were determined for these 3 factors, and their degree of influence and interactions with each other were examined. Aluminum plates with dimensions of 7 cm x 2 cm x 1.5 mm were used as samples in the experimental studies. 3 different sandpapers (400, 600 and 800) were used in the sanding process of the samples. Etching and modification processes were carried out with 2 different experimental studies. In both studies, 9 different experiments were carried out in L9 orthogonal arrangement using Minitab 18 program. In the first experimental study; the sandede samples, were immersed in 4 M hydrochloric acid (HCl) solution for 2, 4 and 6 minutes and etched. For the modification, the etched surfaces were immersed in an ethanolic solution of dodecyltriethoxysilane at a concentration of 0.01 M for 8, 16 and 24 hours. In the second series of experimental studies; etching processes were carried out sequentially with base + acid treatment. Here, sanded samples were etched by 1 M sodium hydroxide (NaOH) solution for 10 minutes. Then, a second etching was carried out by immersing it in a solution of 20 ml distilled water (H2O): 8 ml HCl: 1 ml (acetic acid) CH3COOH for 3, 5 and 10 minutes. In the modification process, the etched samples were immersed in an ethanolic solution of 2 % by mass of palmitic acid for 15, 30 and 60 minutes. The superhydrophobic properties of the surfaces were determined with the contact angle measuring device and the surface morphologies were examined by Scanning Electron Microscope (SEM). According to the contact angle results; in both studies, contact angles of over 150° were obtained and aluminum surfaces were determined as superhydrophobic. In SEM images; the rough superhydrophobic surfaces were observed. According to the results; it has been determined that the applied method can be used in the development of superhydrophobic coatings on aluminum surfaces.

Synthetic dyes are harmful to human beings, and the removal of colour from process or waste effluents is environmentally important. Crystal violet (CV) is a typical triphenylmethane dye, which is widely used in textile dyeing and paper printing industries. The present study shows that granulated and calcinated waste mussell shells (CWMS) can be used as a potential low-cost and locally available adsorbent for the removal of CV from aqueous solutions. The adsorption capacities of the CWMS for CV were investigated with respect to the effect of pH value, adsorbent dosage, contact time, initial dye concentration and temperature. Process variables were optimized, and a maximum dye adsorption of 482.0 mg/g was achieved at pH 6, 0.2 g/L adsorbent dosage, 220 min contact time and 25 °C for dye initial concentration of 100 mg/L. Adsorption kinetics and isotherms were followed by the pseudo-second order model and Freundlich isotherm models, respectively. Thermodynamic parameters demonstrated that adsorption of CV was spontaneous and endothermic in nature. The results indicated that the CWMS as a new adsorbent had the potential to serve in wastewater treatment applications, especially in the removal of CV from aqueous solutions.

Dandıl, Sahra (Bilecik Author) Açıkgöz, Çağlayan (Bilecik, Author) This study dealt with preparation of the activated carbon derived from active sludge as an adsorbent for the adsorption of crystal violet (CV) from aqueous solution. The waste active sludge was activated chemically with KOH and carbonized to get activated carbon with a large surface area and a high porosity. The activated carbon was characterized by Fourier transform infrared (FTIR) spectroscopy, Brunauer-Emmett-Teller (BET) instrument, and scanning electron microscopy (SEM). Adsorption of CV from aqueous solution onto the activated carbon was investigated under varying conditions, such as adsorbent dosage (1-6 g/L), solution pH (4-9), contact time period (0-150 min), initial dye concentration (20-100 mg/L), and temperature (25-55 degrees C). 4.0 g/L of adsorbent dosage was chosen as the optimum level due to having a high removal rate (96.2%) (initial CV concentration 60 mg/L; 150 rpm; pH 6; 25 degrees C). The adsorption kinetic and adsorption isotherms were well described by the pseudo second order kinetic and the Freundlich isotherm model, respectively. The thermodynamic parameters indicated that the adsorption is a spontaneous process and favored at higher temperatures. The results show that the activated carbon derived from active sludge could be employed as a low-cost material for the removal of CV dye. WOS:000486383800004 Q4

Environmental pollution problems by the discharge of effluent containing various contaminations from textile, paper and paint industries have become a serious issue in recent years. Dye removal from wastewater has received considerable attention for several adsorbents and several classes of dye. Reactive black 8 is an environmentally hazardous dye and most applicable in textile industries. Chitosan is a non-toxic, biodegradable and biocompatible and acts as an efficient adsorbent because of the amino functional groups. In the present work, the crosslinked chitosan beads were synthesized by using glutaraldehyde as a crosslinker and the adsorptive removal of reactive black 8 by the beads from an aqueous solution was investigated. The effect of contact time and initial dye concentration was evaluated. The adsorbent dosage was retained as 1 g/L and initial dye concentration values were varied from 30 to 150 mg/L. Equilibrium isotherms were analysed by Langmuir, Freundlich, Dubnin–Radushkevich, and Temkin isotherm. Freundlich isotherm model was found fit effectively for the reactive black 8 adsorptions. Kinetic adsorption data were evaluated using the pseudo-first-order kinetic model, the pseudo-second-order kinetic model and the intraparticle diffusion model. The adsorption followed pseudo second order kinetics. Overall, this study indicates chitosan beads as an efficient, eco-friendly and low-cost adsorbent for the removal of reactive black 8 dye from aqueous solutions.