• 한국물환경학회지
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• 제23권3호
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• pp.314-318
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• 2007

The feasibility of the employment of waste oyster shell as an adsorbent for fluoride ion has been tested by considering the effect ionic condition on the adsorption of fluoride ion on oyster shell. The adsorption capacity of oyster shell for fluoride ion was found not to be significantly influenced by the ionic strength of aqueous environment. The existence of complexing agent such as nitrilotriacetic acid in wastewater decreased the adsorbed amount of fluoride ion by forming a stable complex of $CaT^-$ and the adsorption reaction of fluoride ion on oyster shell was examined to be endothermic. The coexisting heavy metal ionic adsorbate in wastewater hindered the adsorption of fluoride ion, however, its adsorbed amount was increased as the particulate size of adsorbent was decreased. Finally, a serial adsorption column test has been conducted for a practical application of adsorption process and the breakthrough of the column adsorption was observed in 22 hours under the experimental condition.

• 대한화학회지
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• 제57권1호
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• pp.104-108
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• 2013

The adsorption characteristics of Cd(II) and Pb(II) in aqueous solution using granular activated carbon (GAC), activated carbon fiber (ACF), modified ACF (NaACF), and a mixture of GAC and NaACF (GAC/NaACF) have been studied. The surface properties, such as morphology, surface functional groups, and composition of various adsorbents were determined using X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) measurements. The specific surface area, total pore volume, and pore size distribution were investigated using nitrogen adsorption, Brunauer-Emmett-Teller (BET), and Barrett-Joyner-Halenda (BJH) methods. In this study, NaACF showed a high adsorption capacity and rate for heavy metal ions due to the improvement of its ion-exchange capabilities by additional oxygen functional groups. Moreover, the GAC and NaACF mixture was used as an adsorbent to determine the adsorbent-adsorbate interaction in the presence of two competitive adsorbents.

• 한국환경과학회지
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• 제15권11호
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• pp.1053-1059
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• 2006

This study was performed to investigate the possible uses of waste sludge for the removal of heavy metal ions. The adsorption experiments were conducted with wastes such as sewage treatment sludge, water treatment sludge and oyster shell to evaluate their sorption characteristics. Heavy metals selected were cadmium, copper and lead. in the sorption experiments on the sewage treatment sludge, water treatment sludge, oyster shell and soil, sorption occurred in the beginning and it reached equilibrium after 40 minutes on the oyster shell and 4 hour on the sewage treatment sludge and water treatment sludge. Results of Freundlich isotherms indicated that sewage treatment sludge could be properly used as an adsorbent for heavy metals and sorption strength of heavy metals was in the order of Pb > Cu > Cd. In the influence of pH on the adsorbents, sorption rate was more than 80% in pH 4 and most of heavy metals were adsorbed in pH 9. Adsorption rate of Cd decreased with decreasing pH and then adsorption rate of Cu was lower in soil.

• 공업화학
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• 제29권5호
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• pp.571-580
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• 2018

본 연구에서는 수용액에서 Pb(II)를 흡착 제거하기 위하여 커피찌꺼기(spent coffee grounds; SCG)와 점토광물인 견운모(sericite)를 혼합하여 복합흡착제(SS)를 제조하였다. FT-IR 분석결과 SS의 주요 관능기는 O-H, C=O와 C-N 그룹이었다. SS의 비표면적, 기공직경 그리고 양이온 치환 용량은 SCG와 sericite보다 크고, 높았다. SS 흡착제 제조를 위한 최적의 조건은 소성온도 $300^{\circ}C$, SCG : sericite 비율 8 : 2, 입자의 크기는 0.3 mm이었다. SS 흡착제를 이용하여 Pb(II)를 제거하기 위한 실험에서는 Langmuir 흡착식이 Freundlich보다 적합하였으며, Langmuir 등온흡착식에 의한 Pb(II)의 최대 흡착용량은 44.42 mg/g이었다. 또한, 열역학 분석에 의하면 SS 흡착제를 이용한 Pb(II)의 흡착 공정은 물리적인 흡착이었으며, 자연적인 발열반응이었다. SS 흡착제의 흡착-탈착 실험에서는 88-92%를 회수할 수 있었으나, 탈착 횟수가 증가할수록 SS 흡착제의 활성사이트는 감소하였다. 위의 실험결과 SS 흡착제는 전처리 없이 저렴하고, 효율적으로 Pb(II)를 수용액에서 흡착 제거할 수 있다.

• Advances in environmental research
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• 제6권3호
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• pp.173-187
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• 2017

Heavy metals, such as vanadium, are some of the most toxic types of water contaminants. In this study, vanadium was removed using a new composite adsorbent called BAZLSC. The impacts of pH and initial concentration of vanadium(V) on the elimination effectiveness of this metal by using BAZLSC were investigated in the first step of the study. Vanadium removal increased as pH increased to 3-3.5, and initial concentration increased to 60-70 mg/L. The removal efficiency then decreased. Central composite design and response surface methodology were employed to examine experimental data. Initial concentration of V ($mg.L^{-1}$), pH, and dosage of adsorbent (g/L) were the independent factors. Based on RSM, the removal effectiveness of vanadium was 86.36% at the optimum of initial concentration (52.69 mg/L), pH (3.49), and adsorbent dosage (1.71 g/L). Also adsorption isotherm investigations displayed that the Freundlich isotherm could explain vanadium adsorption by BAZLSC better than the Langmuir isotherm. Beside them, desorption studies showed sorption was slightly diminished after six continuous cycles.

• 한국환경보건학회지
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• 제21권3호
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• pp.77-86
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• 1995

Lead(II) removal efficiency by natural kaolinite was investigated through laboratory experiments. This study was conducted in two phases-sorption and desorption. In the adsorption study, the influence of sorption kinetics and sorption isotherm and various parameters such as pH, temperature, coexisting other heavy metal ions on the lead adsorption was investigated. And desorption study was carried out in order to find the re-usability of kaolinite as an adsorbent. The results of the study are as follows. 1. Sorption kinetics was investigated under the condition of 2.5 mg/l adsorbent concentration, pH 6.5$\pm$0.05, temperature $30\pm 0.5\circ$C, initial lead(II) concentration 25 mg/l. Adsorption rate was initially rapid and the extent of adsorption arrived at adsorption equilibrium with 73% adsorption efficiency in an hour. 2. The sorption isotherm experiment was made with different initial lead(II) concentration. A linearized Freundlich equation was used to fit the acquired experimental data. As a result, Freundlich constants, the sorption intensity (1/n) was 0.47 and the measure of sorption (k) was 2.44. So, it was concluded that sorption of lead(II) by kaolinite is effective. 3. The effect of pH on lead(II) sorption by kaolinite shows that at a pH of 3, only 6% of the total lead(II) was adsorbed and at a pH 9, 97% of the lead(II) was removed. And the effect of temperature on lead(II) sorption by kaolinite shows that as the temperature increased, the amount of lead(II) sorption per unit weight of kaolinite increased. But the effect was minor (p<0.05). 4. Sorption isotherm of lead coexisting cadmium (II) or zinc (II) was lower than that of lead itself. It was caused by the result of competitive sorption to adsorption site. And there was no difference between the sorption isotherm of cadmium and zinc. 5. In desorption studies, only 5.12% desorption took place in distilled water, while 52.08% in 0.1 N hydrochloric acid. Consequently used kaolinite could be regenerated by hydrochoric acid.

• 한국토양비료학회지
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• 제46권1호
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• pp.8-15
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• 2013

참깨 부산물의 중금속 흡착제로서 가능성을 검토하기 위해 $600^{\circ}C$에서 1시간동안 열분해 한 참깨 부산물 biochar를 이용하여 중금속 오염폐수 중의 중금속 흡착특성을 조사하였다. Biochar의 중금속 제거효율은 Pb>Cu>Cd>Zn 순으로 Pb의 흡착효율이 가장 높게 나타났다. 참깨 부산물 biochar를 이용한 흡착실험 결과를 Freundlich와 Langmuir 등온흡 착식에 적용하여 각각의 중금속 인자를 산출한 결과 Langmuir와 Freundlich 등온흡착식 모두에서 Pb의 흡착능력이 Cu, Cd 및 Zn에 비해서 우수한 것으로 나타났다. Pb의 경우는 Langmuir 등온흡착식이 Freundlich 등온흡착식에 비해 더 적합하였으나 Cu, Cd 및 Zn의 경우 저농도에서 약간 차이는 있었으나 두 등온흡착식 모두 적합하였다. 전자현미경 (SEM)을 이용하여 중금속 흡착 전 후의 biochar 표면을 관찰한 결과 중금속 흡착 후에 각각의 중금속이 흡착되어 있는 것을 관찰 할 수 있었다. FT-IR 분석결과 중금속은 주로 방향족 C=O ring stretching ($1160cm^{-1}$ $1384cm^{-1}$ 및 $1621cm^{-1}$)에서 흡착되는 것으로 관찰되었다. 이상의 결과를 미루어 볼 때 참깨 부산물로 제조한 biochar는 중금속 흡착제로서의 활용 가능성이 높을 것으로 판단된다.

• Environmental Engineering Research
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• 제23권3호
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• pp.301-308
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• 2018

We investigated simultaneous removal of heavy metals such as Cr, Ni, and Zn by adsorption onto powdered activated carbon (PAC) and PAC modified with sodium diethyldithiocarbamate (PAC-SDDC). Modification of PAC was confirmed by Fourier transform infrared spectroscopy and Scanning electron microscopy and energy dispersive X-ray spectroscopy. Both PAC and PAC-SDDC reached adsorption equilibrium within 48 h, and the adsorption kinetics followed a pseudo-second order reaction kinetics. The removal of metals was enhanced with increasing both adsorbent dosage and followed the descending order of Cr > Ni > Zn for PAC and Cr > Zn > Ni for PAC-SDDC, respectively. Adsorption kinetics followed pseudo-second order kinetics. Adsorption kinetic results were well fitted by the Freundlich isotherm except for Cr adsorption onto PAC. The optimum pH for heavy metal adsorption onto PAC was 5, whereas that for PAC-SDDC ranged from 7 to 9, indicating that modification of PAC with SDDC significantly enhanced heavy metal adsorption, especially under neutral and alkaline pH conditions. Our results imply that SDDC modified PAC can be applied to effectively remove heavy metals especially Cr in plating wastewaters without adjusting pH from alkaline to neutral.

• 한국환경농학회지
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• 제32권2호
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• pp.108-116
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• 2013

BACKGROUND: Certain crop-based waste materials have been recognized as cost-effective and highly efficient adsorbents for removal and recovery of different kind of heavy metals from aqueous solutions. The ability is strongly attributed to the carboxyl functional group of some pectin substances such as galacturonic acid often found in fruit peels. The present manuscript was aimed at assessing the potential applicability of banana peel for metal removal from contaminated waters. METHODS AND RESULTS: As revealed by laboratory investigations, banana peel contains pectin (10-21%), lignin (6-12%), cellulose (7.6-9.6%), and hemicelluloses (6.4-9.4%). The pectin extraction is reported to have glucose, galactose, arabinose, rhamnose, xylose, and galactouroninc acid. Several studies conducted under different conditions proved that banana peel is capable of adsorbing 5.71, 2.55, 28.00, 6.88, 7.97, and 5.80 mg/g of $Cd^{2+}$, $Co^{2+}$, $Cu^{2+}$, $Ni^{2+}$, $Pb^{2+}$, and $Zn^{2+}$, respectively, from aqueous solutions. Adsorption capacity is, however, dependent upon several factors including solution pH, dose of adsorbent and metal concentration, contact time and shaking speed. CONCLUSION(S): Since the annual world production of banana exceeds 100 million tons, about 40 million tons of banana peel (40% of total weight of the fresh fruit) remains vastly unused. Exploring a sound technology with banana peel would therefore, not only address the much needed sustainable tool for cleaning contaminated waters, but of course bring an additional value to the banana industry worldwide.

• 한국지반신소재학회논문집
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• 제13권2호
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• pp.59-67
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• 2014

이 연구는 중금속 오염물질의 효과적인 정화를 위하여 배수재에 흡착가능한 오염물질의 양을 평가하는 것이고 배수재의 오염 물질 흡착능은 배수재 필터에 도포된 반응물질의 오염물질 흡착시험을 수행하고, 등온흡착모델과 비교하여 평가하였다. 시험에서 사용한 반응물질은 천연 제올라이트이고, 오염물질은 구리, 납, 카드뮴이다. 오염물질별로 초기농도 변화에 따른 흡착량을 Freundlich와 Langmuir흡착등온모델과 비교하였다. 배수재 표면에 도포된 반응물질 성분분석결과 Si, Al, O의 성분이 각각 약 28%, 11%, 48% 포함되어 있어 배수재 표면에 도포된 물질이 중금속(Cu, Pb, Cd) 오염물질 흡착을 위한 반응물질인 제올라이트의 성분으로 나타났다. 반응물질인 제올라이트의 중금속 흡착반응속도는 납, 구리, 카드뮴의 순으로 나타났다. 흡착물질의 성능평가 중 중요한 요소가 반응속도이고, 최대흡착량과 반응속도의 관계에서 제올라이트를 반응물질로 사용할 경우, 지반내 복합중금속의 제거 순서를 결정하는 설계 요소로 활용할 수 있다. 즉, 납은 구리에 비해 최대흡착량은 작지만 상대적으로 반응속도가 빠르므로 1차적으로 제거가 가능하며, 납의 제거 후 구리의 제거가 가능하다. 카드뮴의 경우 다른 중금속의 제거 후 마지막으로 제거가 가능한 것으로 분석되었다.