• 한국물환경학회지
• /
• 제21권6호
• /
• pp.569-574
• /
• 2005

In this study, alginic acid that had an high affinity for a heavy metal and was noted for biological adsorbent was modified by an oxidizer, $KMnO_4$. Chemical modification changed hydroxyl of the alginic acid into carboxyl and compare with alginic acid, modified alginic acid exhibited a characteristics that carboxyl groups are comparatively high. For the use of them as an adsorbent, beads were prepared by dropping alginic acid and modified alginic acid solution in dilute 2 wt% $CaCl_2$ solution for non water soluble. The amount of removed $Cu^{2+}$ and $Pb^{2+}$ by modified alginic acid beads showed 84.7 mg and 90.9 mg per gram of beads, respectively. And it showed the amount of adsorbed heavy metal ions 10~20% higher than that of alginic acid beads in range of pH 4~7. In particular, modified alginic acid have a good adsorption capacity for $Cu^{2+}$ and $Pb^{2+}$ by Freundlich adsorption isotherm. According to this study, it is verified that alginic acid that is a nature high molecular substance improved capacity for actual application by increased heavy metal adsorption capacity by chemical modification.

• 한국환경과학회지
• /
• 제23권12호
• /
• pp.1987-1998
• /
• 2014

Zeolite was synthesized from power station waste, coal fly ash, as an alternative low-cost adsorbent and investigated for the removal of Sr(II) and Cs(I) ions from single- and binary metal aqueous solutions. In order to investigate the adsorption characteristics, the effects of various operating parameters such as initial concentration of metal ions, contact time, and pH of the solutions were studied in a batch adsorption technique. The Langmuir model better fitted the adsorption isotherm data than the Freundlich model. The pseudo second-order model was found more applicable to describe the kinetics of system. The adsorption capacities of Sr(II) and Cs(I) ions obtained from the Langmuir model were 1.7848 mmol/g and 0.7640 mmol/g, respectively. Although the adsorption capacities of individual Sr(II) and Cs(I) ions was less in the binary-system, the sum of the total adsorption capacity (2.3572 mmol/g) of both ions in the binary-system was higher than the adsorption capacity of individual ion in the single-system. Comparing the homogeneous film diffusion model with the homogeneous particle diffusion model, the adsorption was mainly controlled by the particle diffusion process.

• Biotechnology and Bioprocess Engineering:BBE
• /
• 제2권2호
• /
• pp.132-135
• /
• 1997

We prepared capsules containing Saccharomyces cerevisiae and Zoogloea ramigera cells for the removal of lead(II) and cadmium ions. Microbial cells were encapsulated and cultured in the growth medium. The S.cerevisiae cells grown in the capule did not leak through the capsule membrane. The dried cell density reached to 250 g/l on the basis of the inner volume of the 2.0 mm diameter capsule after 36 hour cultivation. The dry whole cell expolymer density of encapsulated Z.ramigera reached to 200 g/L. The capsule was crosslinked with triethylene tetramine and glutaric dialdehyde solutions. The cadmium uptake of encapsulated whole cell expolymer of Z.ramigera was 55mg Cd/g biosorbent. The adsorption line followed well Langmuir isotherm. The lead uptake of the encapsulated S. cerevisiae was about 30 mg Pb/g biomass. The optimum pH of the lead uptake using encapsulated S. cerevisiae was found to be 6. Freundlich model showed a little better fit to the adsorption data than Langmuir model 95 percent of the lead adsorbed on the encapsulated biosorbents was desorbed by the 1 M HCl solution. The capsule was reused 50 batches without loosing the metal uptake capacity. And the mechanical strength of the crosslinked capsule was retained after 50 trials.

• 상하수도학회지
• /
• 제10권4호
• /
• pp.103-110
• /
• 1996

Excessive phosphorus (P as orthophosphate) is one of the major pollutants in natural water that are responsible for algal blooms and eutrophication. P removal by slag is an attractive solution if the P sorption capacity of the slag is significant. To design an efficient land treatment facility, basic information on the behaviour of P in the media-water environment is required. In this study, detailed column experiments were conducted to study the P transport under dynamic condition, and mathematical models were developed to describe this process. The column experiments conducted with dust and cake waste products (slag) from BHP steel industry in Australia as adsorbing media indicated that they had higher sorption capacity of P than that of a sandy loam soil from North Sydney, Australia. P transport in the dust and cake columns exhibited characteristics S-shaped or curvilinear breakthrough curves. The simulated results from a dynamic physical non-equilibrium sorption model (DPNSM) and Freundlich isotherm constants satisfactorily matched the corresponding experimental breakthrough data. The mobility of P is restricted proportionally to the adsorbent's sorption capacity.

• 한국물환경학회지
• /
• 제20권5호
• /
• pp.466-472
• /
• 2004

Red mud is formed as a waste during bauxite refining known as Bayer's process. Its main constituents are iron, aluminium, sodium and silica. The disposal of large quantities of wasted red mud causes a serious ecological problem. In this study, the red mud wasted from the bauxite refinery was studied for phosphate removal from aqueous solution according to activation methods. The influence of heat treatment, and neutralization with sea water and acid treatment level for the optimum conditions for phosphate removal have been determined. Heat treatment combined with acid treatment is most suitable for the removal of phosphate from aqueous solution. The optimal condition was activated with 1 N HCl solution after heating in $600^{\circ}C$ during 4 hours. Acid and heat treatment causes sodalite compounds which hinder the phosphate adsorption to leach out. The adsorption data obtained followed a first-order rate expression and fitted well with the Freundlich Isotherm well.

• 대한화학회지
• /
• 제17권5호
• /
• pp.319-323
• /
• 1973

무단체 Ag-111의 상태를 여과법에 의하여 연구하였다. 이 연구는 막여과자에 의하여 수용액에 있어서 Ag-111의 pH 및 농도변화에 대한 효과를 조사하였다. 이 연구결과 막여과지에 대한 Ag-111의 부착은 Freundlich 흡착 등온식에 따르고 Ag-111의 흡착상태는 AgOH 형태로 존재하며 높은 pH에서 흡착성이 없는 $Ag(OH)_{2}-$는 Ag의 흡착을 방해하는 것으로 생각된다. 또한 무단체 Ag-111는 수용액중에서 $Ag^+$상태로 존재하고 있다.

• 상하수도학회지
• /
• 제21권1호
• /
• pp.27-36
• /
• 2007

Milled Korean pine (Pinus densiflora) wood was used to evaluate its adsorption capacity of Cu(II) ions from aqueous solution by running a series of batch experiments. Prior to the tests, the milled woods were pretreated with 1N NaOH, 1N $NHO_3$, and distilled water, respectively, to examine the effect of pretreatment. Within the tested pH range in this study between 3 and 6, copper adsorption efficiency of NaOH-treated wood(96~99%) was superior than $NHO_3$-treated wood(19~31%) and distilled water-treated wood(18~35%). Adsorption behavior of copper onto both raw and $NHO_3$-treated woods was mainly attributed to interaction with carboxylic acid group. For NaOH-treated wood, carboxylate ion produced by hydrolysis was a major functional group responsible for Cu sorption. NaOH treatment of wood changed the ester and carboxylic acid groups into carboxylate group, whereas $NHO_3$ treatment did not affect the production of functional groups which could bind copper. A pseudo second-order kinetic model fitted well for the sorption of copper ion onto NaOH-treated wood. A batch isotherm test using NaOH-treated wood showed that equilibrium sorption data were better represented by the Langmuir model than the Freundlich model.

• Environmental Engineering Research
• /
• 제11권6호
• /
• pp.303-310
• /
• 2006

The aim of this study is to assess the applicability of sericite in wastewater treatment particularly the removal of two important heavy metal toxic ions viz., Cu(II) and Pb(II) from aqueous solutions. The batch type experiments showed that sericite is found to be one of useful natural sorbent for the removal of these two cations from aqueous solutions and it is also to be observed that with the increase in sorptive concentration amount of metal uptake increases and the concentration dependence data obtained are fitted well for the Langmuir adsorption isotherm rather than Freundlich adsorption model. Further, the Langmuir monolayer adsorption capacity is found to be $1.674\;mg\;g^{-1}$ for Cu(II) and $4.697\;mg\;g^{-1}$ for Pb(II). Kinetic studies enabled, an apparent equilibria can be achieved between soild/solution interface within ca 10 mins for Cu(II) and ca 90 mins for Pb(II). Moreover, the removal behavior of sericite for these two metal ions is greatly influenced by solution pH.

• Environmental Engineering Research
• /
• 제24권4호
• /
• pp.608-617
• /
• 2019

The adsorption of sulfamethoxazole (SMX) onto a NaOH-activated pine wood-derived biochar was investigated via batch experiments and models. Surprisingly, the maximum adsorption capacity of activated biochar for SMX (397.29 mg/g) was superior than those of pristine biochars from various feedstock, but comparable to those of commercially available activated carbons. Elovich kinetic and Freundlich isotherm models revealed the best fitted ones for the adsorption of SMX onto the activated biochar indicating chemisorptive interaction occurred on surface of the activated biochar. In addition, the intraparticle diffusion limitation was thought to be the major barrier for the adsorption of SMX on the activated biochar. The main mechanisms for the activated biochar would include hydrophobic, π-π interactions and hydrogen bonding. This was consistent with the changes in physicochemical properties of the activated biochar (e.g., increase in sp² and surface area, but decrease in the ratios of O/C and H/C).

• Nuclear Engineering and Technology
• /
• 제49권1호
• /
• pp.172-177
• /
• 2017

A novel biosorbent, immobilized Saccharomyces cerevisiae in magnetic chitosan microspheres was prepared, characterized, and used for the removal of $Sr^{2+}$ from aqueous solution. The structure and morphology of immobilized S. cerevisiae before and after $Sr^{2+}$adsorption were observed using scanning electron microscopy with energy dispersive X-ray spectroscopy. The experimental results showed that the Langmuir and Freundlich isotherm models could be used to describe the $Sr^{2+}$ adsorption onto immobilized S. cerevisiae microspheres. The maximal adsorption capacity ($q_m$) was calculated to be 81.96 mg/g by the Langmuir model. Immobilized S. cerevisiae was an effective adsorbent for the $Sr^{2+}$ removal from aqueous solution.