In the present study, biomass of Agaricus campestris was tested to evaluate its effectivity as a biosorbent for the removal of Cr (VI) ions from aqueous solutions. The influence of various process parameters such as pH, temperature, contact time, biosorbent dosage and desorption were studied. Pseudo-first order, pseudo-second order, Ritchies and intraparticle diffusion model were used to present the adsorption kinetics. Results obtained indicate that the adsorption process is fast and spontaneous within the first 60 min. The experimental data supports pseudo-second order model. The sorption data conformed well to the Langmuir isotherm model. The maximum adsorption capacity (q_max) onto A. campestris was 56.21 mg g^-1 for Cr(VI) at 45 °C when 0.1 g biomass was used. In addition, the mean values of thermodynamic parameters of standard free energy (ΔG⁰= −1.635 kJ mol⁻¹ at 45 °C), standard enthalpy (ΔH⁰= -9.582 kJ mol⁻¹) and standard entropy (ΔS⁰= -24.992 J mol⁻¹K⁻¹) of the adsorption mechanism were determined.

In this study, poly (hydroxyethyl methacrylate) (PHEMA) nanobeads with an average size of 115 nm were prepared by emulsion polymerization. The nanobeads were characterized with infrared spectroscopy, scanning electron microscopy, and zeta size analysis. The surface area of the PHEMA nanobeads was calculated as 541.4 m²/g. Then, diethyl phthalate (DEP) removal efficiency of the PHEMA nanobeads from aqueous media was investigated. At a fixed adsorbent/solution ratio, various factors affecting the adsorption of DEP from aqueous solution such as pH, initial concentration, contact time, temperature, and adsorbent dosage were analyzed. The maximum DEP adsorption capacity of the PHEMA nanobeads was determined as 265.1 mg/g at pH 4.0, 25°C. The Sips isotherm model fits the experimental data in the wide range of DEP concentration tested (1–300 mg/L). The pseudo-first-order, pseudo-second-order, modified Ritchie’s-second-order kinetic models were used to test the adsorption kinetics. The DEP adsorption capacity of the nanobeads did not change after five batch successive usages. DEP removal efficiency of the PHEMA nanobeads from different water media such as saliva, sweat, and tap water was also evaluated. The removal efficiencies in the range from 82.4 to 100.0% demonstrate the usability of PHEMA nanobeads for DEP removal from real samples.

Bu çalışmada, Direct Blue 2 (DB2) tekstil boyar maddesinin Agaricus campestris’ten elde edilen biyosorbent ile sulu çözeltilerden giderimi çalışılmıştır. Biyosorpsiyona pH, sıcaklık, başlangıç DB2 derişimi ve biyosorbent miktarı gibi parametrelerin etkisi incelenmiştir. Optimum pH’ın 6.0 olarak tespit edildiği koşullarda 100 mg L-1 başlangıç DB2 derişimi ve 0.01 g biyosorbentin kullanıldığı koşullarda maksimum biyosorpsiyon kapasitesi 38.56 mg g-1, 0.2 g biyosorbentin kullanıldığı koşullarda ise % tutunma miktarının % 93.39 olarakbulunmuştur. Elde edilen sonuçlara göre biyosorpsiyonun Freundlich izoterm modeline ve yalancı-ikinci derece kinetik modele uygun olduğu rapor edilmiştir. Son olarak, biyosorpsiyon mekanizması için termodinamik parametreler (standart serbest enerji, standart entalpi ve standart entropi) belirlenmiştir

Bu çalışmada, Lactarius salmonicolor biyokütlesinin tekstil boyar maddesi olan Remazol Marine Blue (RMB)'nun gideriminde biyosorbent olarak kullanımı araştırılmıştır. pH, başlangıç boya derişimi, sıcaklık, temas süresi ve biyokütlenin tekrar kullanımı gibi birçok parametre kesikli sistemde araştırılmıştır. Elde edilen verilere göre kinetik, termodinamik ve izoterm gibi bazı fizikokimyasal parametreler hesaplanarak, biyosorpsiyonun doğası aydınlatılmaya çalışılmıştır. pH: 3'de, 0,8 g/L biyosorbent miktarının kullanıldığı koşullarda 100 mg/L başlangıç RMB'nun biyosorpsiyon kapasitesi 35 ºC'de 126,57 mg/g bulunmuştur. Biyosorpsiyon yalancı-ikinci derece kinetik modele uyumlu ve kendiliğinde gerçekleşen bir proses olduğu bulunmuştur.

In this study, the adsorption of tetracycline (TC) onto polymeric microbeads was investigated. For this purpose, suspension polymerization was used to synthesize poly(2-hydroxyethyl methacrylate) [poly(HEMA)] microbeads. Cibacron Blue F3GA (CB) was covalently attached to poly(HEMA) microbeads and the microbeads were tested as an adsorbent for subsequent TC adsorption. The effects of various parameters, such as pH value, initial TC concentration, temperature, and contact time, were investigated. The maximum adsorption capacity (Q) of microbeads was found to be 9.63 mg g-1 at pH 7.0. The results showed that the adsorption process was fast and occurred spontaneously within the first 5 minute. The adsorption process was fitted to the Freundlich isotherm model. The thermodynamic parameters of the adsorption, the enthalpy (∆H°) and entropy (∆S°), were calculated as 69.26 kJ mol-1 and 0.290 kJ mol-1 K-1, respectively. The Gibbs free energy (∆G°) was also calculated in the range of -11.069 kJ mol-1 to -17.159 kJ mol-1 with increase in temperature from 277 K to 298 K indicating that the TC adsorption process was spontaneous and endothermic. The results revealed that the poly(HEMA) microbeads could be effectively used to adsorption of TC from aqueous solution.