Adsorption characterization of Pb(ii) ions onto iodate doped chitosan composite: equilibrium and kinetic studies

RSC Advances ◽  
2015 ◽  
Vol 5 (67) ◽  
pp. 54188-54201 ◽  
Author(s):  
Asha H. Gedam ◽  
Rajendra S. Dongre

Iodate doped chitosan (I-CS) composite was synthesized, characterized and used as an adsorbent for adsorption of Pb(ii) ions from aqueous solution.

2017 ◽  
Vol 2017 ◽  
pp. 1-11
Author(s):  
Nguyen Thi Hue ◽  
Nguyen Hoang Tung

Lanthanum has been doped onto the surface of the natural Pyrolusite for simultaneous removal of phosphate and fluoride in aqueous solution. The adsorbent characterization of the materials was observed by the SEM, BET, and XRD techniques. The dynamics and isotherms models of fluoride and phosphate adsorption, with respect to pH, pHPZC, adsorbent dose, and effect of coexisting ions, were studied. The results showed that lanthanum doped Pyrolusite ore (LDPO) relatively highly adsorbed amount of phosphate and fluoride from aqueous solution. Phosphate and fluoride removal efficiencies of LDPO are approximately 97% and 95%, respectively. Pseudo-first order for kinetic studies of phosphate and fluoride removal of the LDPO was observed with high correlations for fluoride but weak correlations for phosphate. However, pseudo-second order for kinetic studies was high correlation for both phosphate and fluoride. The phosphate and fluoride adsorption capacities of the LDPO significantly decreased with the existence of coions (sulfate, chloride, and nitrate) in the aqueous solution.


2015 ◽  
Vol 22 (2) ◽  
pp. 233 ◽  
Author(s):  
Poedji Loekitowati Hariani ◽  
Fatma Fatma ◽  
Fahma Riyanti ◽  
Hesti Ratnasari

Phenolic compounds areorganic pollutants that are toxic and carcinogenic.The presence of phenol in the environmentcan be adverse to humanand the environmentalsystem. One methodthat iseffective toreduce thephenolisadsorption. In this study, the adsorption of phenol in aqueous solution using Ca-bentonite/chitosan composite was investigated. Chitosan is the deacetylation product of chitin from shrimp waste. Characterization of Ca-bentonite/chitosan composite was done by using Fourier Transform Infrared (FTIR) and Scanning Electron Microscopy-Energy Dispersive X Ray Spectroscopy (SEM-EDX). Batch adsorption studies were performed to evaluate the effects of some parameters such as initial concentration of phenol, composite weight, pH and contact time. The results showed that FTIR spectra of Ca-bentonite/chitosan composite presented the characteristic of peak of Ca-bentonite and chitosan that confirmed the successful synthesis of composite. The SEM-EDX characterizationresultsshowedCa-bentonite surfacecoverage by chitosanand the presence ofcarbonandnitrogenelementsinCa-bentonite/chitosancompositeindicated that chitosan had bonded with bentonite. The optimum condition of adsorption of Ca-bentonite/chitosan to phenol was obtained at 125 mg.L-1 of concentration in which the weight of composite was 1.0 g, the pH of solution was 7, the contact time was 30 minutes, and the capacity of adsorption was 12.496 mg.g-1.


2012 ◽  
Vol 602-604 ◽  
pp. 1186-1189
Author(s):  
Zhi Jie Geng ◽  
Song Bai Lin ◽  
Gao Shuang Huang ◽  
Ai Ru Ke

P(DMAA-co-AM)hydrogel; adsorption method; a-amylase; Immobilized enzyme. Abstract. P(DMAA-co-AM)hydrogel was prepared by aqueous solution polymerization with N,N-dimethylacrylamide(DMAA) and acrylamide(AM) as monomers.,taking the P(DMAA-co-AM) hydrogel as carrier, a-amylase was immobilized by adsorption method.The investigation of effection of temperature and pH on enzymatic activity exhibites that the optimum temperatures are 50°C for both free and immobilized enzyme,the maximum activity is observed at pH 6.0 for both free and immobized enzyme. The activity of immobilized a-amylase remaines higher 40% at sixth run. Kinetic studies demonstrate that: Km values are 5.15749 and 1.44479 mg/mL for free and immobilized enzyme, Vmax values are 2.56082 and 0.58272 mg/mL min-1 for free and immobilized enzyme.


Agriculture ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 295
Author(s):  
Marina Moura Morales ◽  
Nicholas Brian Comerford ◽  
Maurel Behling ◽  
Daniel Carneiro de Abreu ◽  
Iraê Amaral Guerrini

The phosphorus (P) chemistry of biochar (BC)-amended soils is poorly understood. This statement is based on the lack of published research attempting a comprehensive characterization of biochar’s influence on P sorption. Therefore, this study addressed the kinetic limitations of these processes. This was accomplished using a fast pyrolysis biochar made from a mix of waste materials applied to a highly weathered Latossolo Vermelho distrofico (Oxisol) from São Paulo, Brazil. Standard method (batch method) was used. The sorption kinetic studies indicated that P sorption in both cases, soil (S) and soil-biochar (SBC), had a relatively fast initial reaction between 0 to 5 min. This may have happened because adding biochar to the soil decreased P sorption capacity compared to the mineral soil alone. Presumably, this is a result of: (i) Inorganic phosphorus desorbed from biochar was resorbed onto the mineral soil; (ii) charcoal particles physically covered P sorption locations on soil; or (iii) the pH increased when BC was added SBC and the soil surface became more negatively charged, thus increasing anion repulsion and decreasing P sorption.


2019 ◽  
Vol 943 ◽  
pp. 95-99
Author(s):  
Li Jun Wang ◽  
Kazuo Umemura

Optical absorption spectroscopy provides evidence for individually dispersed carbon nanotubes. A common method to disperse SWCNTs into aqueous solution is to sonicate the mixture in the presence of a double-stranded DNA (dsDNA). In this paper, optical characterization of dsDNA-wrapped HiPco carbon nanotubes (dsDNA-SWCNT) was carried out using near infrared (NIR) spectroscopy and photoluminescence (PL) experiments. The findings suggest that SWCNT dispersion is very good in the environment of DNA existing. Additionally, its dispersion depends on dsDNA concentration.


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