Tin bis(monohydrogen orthophosphate) monohydrate 물질의 흡착 성질에 관하여 KCl 수용액을 통하여 조사하였다. 금속이온 농도와 pH를 변화시키면서 어떻게 달라지는지 화학평형에 바탕을 두고 data를 분석하였다. 금속이온들의 흡착 data는 Langmuir 흡착식에 넣어 Langmuir 수치들을 얻는데 사용되었다. Tin phosphate는 산성에서 이온교환 화합물로 작용하였으며, 2가의 전이금속이온에 대해 Cu+2 > Co+2 > Ni+2의 순서로 선택적 흡착성질을 나타내었다. 약한 산성 이온 교환체에서와 같이 금속이온의 교환은 tin phosphate의 선택성을 결정하는데 결정적 역할을 하였다. 모든 경우에서 흡착의 정도는 온도와 농도의 증가와 함께 증가하였다. Lnngmuir 수치들은 흡착과정 동안의 엔트로피, 엔탈피, 자유에너지 변화량같은 열역학적 함수들을 계산하는데 이용되었다.

Phosphorus is one of the limiting nutrients for the growth of phytoplankton and algae and is therefore one of leading causes of eutrophication. Most phosphorous in water is present in the form of phosphates. Different technologies have been applied for phosphate removal from wastewater, such as physical, chemical precipitation by using ferric, calcium or aluminum salts, biological, and adsorption. Adsorption is one of efficient method to remove phosphates in wastewater. To find the optimal media for phosphate removal, physical characteristics of media was analysed, and the phosphate removal efficiency of media (silica sand, slag, zeolite, activated carbon) was also investigated in this study. Silica sand showed highest relative density and wear rate, and phosphate removal efficiency. Silica sand removed about 36% of phosphate. To improve the phosphate removal efficiency of silica sand, Fe coating was conducted. Fe coated silica sand showed 3 times higher removal efficiency than non-coated one.

친환경화소재 음이온 교환막을 제조하기 위하여 수용성 PVA에 (Formylmethyl) triphenyl-phosponium chloride의 모노머를 아세틸화 반응에 의해 고정시켰다. 제조한 막의 특성을 분석하기 위해 FTIR, TGA. SEM등의 기기분석장치 및 물리 화학적 기본 특성인 IEC, Transport number, MER등을 조사하였고 이에 대한 거동을 보고하고자한다.

운반체(감응물질)로 제 4급 인산염을 사용하여 PVC를 지지체로 하여 과염소산이온의 농도 10-6 M까지 선형적인 이온선택성 전극을 제작하였다. 운반체의 화학적구조와 함량 가소제의 종류 및 막 두께에 따른 전극의 기울기 선형응답범위 및 한계측정농도 등 전극전위특성을 고려하여 최적의 과염소산 이온선택성 PVC막 전극을 제조한 다음 측정 가능한 pH 범위 선택계수 및 전극의 교류임피던스 특성을 비교 검토하였다 운반체로 tetraoctyl-phosphonium perchlorate(TOPP) tetraphenylphosphonium perchlorate(TPPP) 및 tetrabutylphosponium perchlorate (TBPP) 등의 제 4급 인산염의 과염소산 이온 치환체를 사용하였다 알킬기의 탄소고리 수가 증가할수록 전극특성은 TBPP, 선형응답범위 10-1×10-6 M 및 한계측정농도는 9.66×10-7 M 이었으며 시판되고 있는 Orion 전극특성보다 좋은 결과를 나타내었다 전극전위는 pH3~11범위에서 ph의 영향을 받지 않았으며 CIO4 에 대한 방해이온의 선택계수 서열은 SO24 < F < Br < I 이었다 임피던스 측정결과 TOPP의 경우 등가회로는 용액저항 이중층용량과 벌크저항의 병렬 및 Warburg 임피던스의 직렬이었다 이 경우 용액저항은 거의 나타나지 않았고 확산에 의한 Warburg 임피던스는 크게 나타났으며 Warburg 계수는 1.32×1074 Ω cdot cm2/s1/2이었다.

생체내에서 매식되는 타이타늄의 표면에 골의 형성과 성장을 촉진시키기 위해 칼슘이온과 인산이온을 함유하는 용액에서 타이타늄의 표면처리를 행하였다. 표면처리방법으로는 pH 5.8, 7.0, 8.0의 인산칼슘 완충용액에 10분간 침적시킨 후 유사체액에 30일간 침적시켰다. 침적시킨 후의 타이타늄 표면에 형성된 피막의 특성을 주사전자현미경, X-ray 회절장치, Fourier 변환강도계등으로 확인하고 유사체액에만 침적한 시편의 표면특성과 비교하였다. 실험결과 인산완충용액에서의 침적에 의해 타니타늄 표면에 인산칼슘 형성이 촉진됨을 알 수 있었다. 형성된 층은 입자형의 미세구조를 지닌 하이드록시아파타이트나 β-TCP의 인산칼슘 층으로 확인되었다. 형성된 층의두께는 pH 8.0, 7.0 그리고 pH 5.8의 인산완충액에서의 침적 순으로 증가하였고, 그 밀도는 pH 7.0, pH8.0그리고 pH5.8의 인산완충액에서의 침적 순으로 증가하였다.

최근 환경기준이 강화되면서 하수 처리공정에서 생물학적 처리와 탈인시설을 조합한 하이브리드형 고도처리 공정이 빠르게 도입되고 있다. 현재 도입되고 있는 탈인시설은 대부분 응집제 투여를 바탕으로 하는 화학적 처리공정으로 비교적 처리공정과 유지관리가 간단하여 처리효율의 신뢰도가 높은 장점이 있는 반면에 화학약품 비용과 발생된 슬러지의 처분비용 등이 매우 높다는 단점이 있다. 이에 반해 하이브리드형 고도처리시스템을 구축하는데 있어 가장 단순하고 안정적인 단위공정의 하나로 알려진 흡착법은 이온성 물질의 동시제거가 가능하면서도 기후 및 농도에 관계없이 처리효율이 비교적 일정하고, 부생독성물질을 생성시킬 위험성이 없다는 장점을 가지고 있다. 그럼에도 불구하고 흡착법이 하수처리의 탈인공정으로 널리 활용되지 못하는 이유는 인산이온만을 선택적으로 흡착할 수 있는 흡착제가 없기 때문이다. 최근 저자들은 하수처리수를 이용한 컬럼실험을 통해 강염기성은 물론 약염기성 음이온교환수지 모두 하수 중에 다량 함유되어 있는 황산이온의 방해로 인산이온을 거의 흡착하지 못함을 확인하였다. 즉, 고정층 컬럼 실험을 통해 얻은 인산이온의 흡착량은 인산이온만 있을 경우 134 mg/g인데 반해 실폐수의 경우 Cl과 SO4이온의 흡착경쟁 때문에 10.4 mg/g으로 감소하여 실폐수 적용이 불가능하였다.

This study is mainly focused on micellar effect of tetradecyltrimethyl ammonium bromide(TTABr) solution including alkylbenzimidazole(R-BI) on dephosphorylation of diphenyl-4-nitrophenylphosphinate(DPNPIN) in carbonate buffer(pH 10.7). Dephosphorylation of DPNPIN is accelerated by BI⊖ ion in 10-2 M Carbonate buffer(pH 10.7) of 4×10-4 M TTABr solution up to 80 times as compared with the reaction in Carbonate buffer by no benzimidazole(BI) solution of TTABr. The value of pseudo first order rate constant(kψ) of the reaction in TTABr solution reached a maximum rate constant increasing micelle concentration. The reaction mediated by R-BI⊖ in micellar solutions are obviously slower than those by BI⊖, and the reaction rate were decreased with increase of lengths of alkyl groups. It seems due to steric effect of alkyl groups of R-BI⊖ in Stern layer of micellar solution. The surfactant reagent, TTABr, strongly catalyzes the reaction of DPNPIN with R-BI and its anion(R-BI⊖) in Carbonate buffer(pH 10.7). For example, 4×10-4 M TTABr in 1×10-4 M BI solution increase the rate constant(kψ=99.7×10-4 1/sec) of the dephosphorylation by a factor ca. 28, when compared with reaction(kψ=3.5×10-4 1/sec) in BI solution(without TTABr). And no TTABr solution, in BI solution increase the rate constant(kψ=3.5×10-4 1/sec) of the dephosphorylation by a factor ca. 39, when compared with reaction (kψ=1.0×10-5 1/sec) in water solution(without BI).

This study is mainly focused on micellar effect of cetyltrimethyl ammonium bromide(CTABr) solution including alkylbenzimidazole(R-BI) on dephosphorylation of isopropyl-4-nitrophenylphosphinate(IPNPIN) in carbonate buffer(pH 10.7). The reactions of IPNPIN with R-BI⊖ are strongly catalyzed by the micelles of CTABr. Dephosphorylation of IPNPIN is accelerated by BI⊖ ion in 10-2 M carbonate buffer(pH 10.7) of 4×10-3 M CTABr solution up to 89 times as compared with the reaction in carbonate buffer by no benzimidazole(BI) solution of 4×10-3 M CTABr. The value of pseudo first order rate constant(kψ) of the reaction in CTABr solution reached a maximum rate constant increasing micelle concentration. Such rate maxima are typical of micellar catalyzed bimolecular reactions. The reaction mediated by R-BI⊖ in micellar solutions are obviously slower than those by BI⊖, and the reaction rate were decreased with increase of lengths of alkyl groups. It seems due to steric effect of alkyl groups of R-BI⊖ in Stern layer of micellar solution. The surfactant reagent, CTABr, strongly catalyzes the reaction of IPNPIN with R-BI and its anion(R-BI⊖) in carbonate buffer(pH 10.7). For example, 4×10-3 M CTABr in 1×10-4 M BI solution increase the rate constant(kψ=98.5×10-3 sec-1) of the dephosphorylation by a factor ca.25, when compared with reaction(kψ=3.9×10-4 sec-1) in 1×10-4 M BI solution(without CTABr). And no CTABr solution, in 1×10-4 M BI solution increase the rate constant(kψ=3.9×10-4 sec-1) of the dephosphorylation by a factor ca.39, when compared with reaction (kψ=1.0×10-5 sec-1) in water solution(without BI). This predicts that the reactivities of R-BI⊖ in the micellar pseudophase are much smaller than that of BI⊖. Due to the hydrophobicity and steric effect of alkyl group substituents, these groups would penetrate into the core of the micelle for stabilization by van der Waals interaction with long alkyl groups of CTABr.

In the aqueous solutions the dephosphorylations of isopropyl phenyl-4-nitrophenyl phosphinate(IPNPIN) mediated by hydroxide(OH⊖) and o-iodosobenzoate(IB⊖) ions are relatively slow, because of hydrophobicity of the substrate, and however it appears that OH⊖ is inherently better nucleophile than IB⊖, which is more soft ion. On the other hand, in cetyltrimetylammonium bromide(CTABr) solutions which contain cationic micelles, the dephosphorylations of IPNPIN mediated by OH⊖ or IB⊖ are very accelerated to 120 or 100,000 times as compared with those in the aqueous solutions. The values of pseudo first order rate constants reach a maximum with increasing. Such rate maxima are typical of micellar catalysed bimolecular reactions and the rise in rate constant followed by a gradual decrese is characteristic of reactions of hydrophobic substrates. In the cationic micellar solutions of CTABr, IB⊖ accelerates the reactions much more than that OH⊖ does. The reason seems that IB⊖ which is more hydrophobic and soft ion than OH⊖ is more easily moved into the Stern layer of the CTABr micelles than OH⊖. In the anionic micellar solutions of sodium dodecyl sulfate(SDS), the dephosphorylations of IPNPIN are slower than those in aqeous solutions. It means that OH⊖ or IB⊖ cannot easily move and approach to the Stern layer of the micelle in which almost all the hydrophobic substrate are located and which has a negative circumstance.

This study deals with micellar effects on dephosphorylation of diphenyl-4- nitrophenylphosphate (DPNPPH), diphenyl-4-nitrophenylphosphinate (DPNPIN) and isopropylphenyl-4-nitrophenyl phosphinate (IPNPIN) mediated by OH⊖ or o-iodosobenzoate ion (IB⊖) in aqueous and CTAX solutions. Dephosphorylation of DPNPPH, DPNPIN and IPNPIN mediated by OH⊖ or o-iodosobenzoate ion (IB⊖) is relatively slow in aqueous solution. The reactions in CTAX micellar solutions are, however, much accelerated because CTAX micelles can accommodate both reactants in their Stern layer in which they can easily react, while hydrophilic OH⊖ (or IB⊖) and hydrophobic substrates are not mixed in water. Even though the concentrations (>10-3 M) of OH⊖ (or IB⊖) in CTAX solutions are much larger amounts than those (6×10-6 M) of substrates, the rate constants of the dephosphorylations are largely influenced by the change of concentration of the ions, which means that the reactions are not followed by the pseudo first order kinetics. In comparison to effect of the counter ions of CTAX in the reactions, CTACl is more effective on the dephosphorylation of substrates than CTABr due to easier expelling of Cl⊖ ion by OH⊖ (or IB⊖) ion from the micelle, because of easier solvation of Cl⊖ ion by water molecules. The reactivity of IPNPIN with OH⊖ (or IB⊖) is lower than that of DPNPIN. The reason seems that the 'bulky' isopropyl group of IPNPIN hinders the attack of the nucleophiles.

Adsorption on goethite of individual component from a solution containing phosphate, sulfate, or copper ion was investigated. Competitive adsorption in the binary and ternary solution systems composed of phosphate, sulfate, and copper ions was also investigated. In competitive adsorption systems with phosphate and sulfate ions, the presence of phosphate ion reduced the adsorption of sulfate ion largely. On the other hand, the presence of sulfate ion caused only a small decrease in phosphate adsorption. This result suggests that phosphate ion is a stronger competitor for adsorption on goethite than sulfate ion, which is consistent with the higher affinity of phosphate for the surface compared to sulfate ion. Compared to the results from single-sorbate systems, adsorption of copper ion in the binary system of sulfate ion and copper ion was found to be enhanced in the presence of sulfate ion. Addition of sulfate ion to the binary system of copper ion and phosphate ion resulted in a small enhancement in copper sorption. This result implies that the presence of sulfate ion promotes adsorption of the ternary complex FeOHCuSO4. The adsorption isotherms could be well described by the Langmuir adsorption equation.

Adsorption of phosphate, sulfate, and copper ion to goethite was investigated. Goethite was prepared in the alkaline solution. In the single adsorbate systems, the final equilibrium plateau reached within 20 min. The adsorption isotherms of the individual ions could be well described by the Langmuir equation. The maximum adsorption capacities (qmax) were calculated as 0.483 mmol/g and 0.239 mmol/g at pH 3 for phosphate and sulfate ion, and 0.117 mmol/g at pH 6 for copper ion, respectively. In competitive adsorption system with phosphate and sulfate, phosphate ion was a stronger competitor for adsorption on goethite than sulfate ion, which was consistent with higher affinity of phosphate ion for the surface compared to sulfate ion. The existence of sulfate ion enhanced the adsorption of copper ion but the adsorption of sulfate was inhibited when copper ion was present.

벤토나이트에 포함된 몬모릴로나이트의 층간에 Al산화물의 기둥(pillar)을 만든 Al-층간가교 점토를 합성하였다. 이 Al-층간가교점토에 대해 XRD, DTA, 화학분석 등을 실시하여 광물학적 특성을 검토하였으며, 그리고 이 가교점토에 대하여 Batch법의 흡착실험을 통하여 인산이온의 흡착성을 검토하였다. X-선 회절분석의 결과, Al-층간가교점토는 상온에서 층간격이 18.03 a으로 증가되어 나타났고, 550a가열에서도 약 17a을 나타내어 열적 안정성이 크며, 글리세롤에 의한 층간격의 팽윤은 매우 미약한 것으로 나타났다. 열분석 결과, 이 점토에는 pillar부분에 관련된 물의 탈수에 의한 것으로 보이는 270℃와 420℃의 특징적인 흡열반응이 나타났다. Al-층간가교 점토의 인산 이온에 대한 흡착실험의 결과, 몬모릴로나이트는 거의 흡착능력을 보이지 않는데 비하여 월등히 우수한 인산이온(PO43－ /)성을 나타냈다. 시료 2 g에 용액 20 mL의 실험에서 300 mg/L 이하의 인산 농도에서는 거의 100%의 흡착효율을 나타냈다. 그리고 인산 이온에 흡착된 시료를 500℃로 가열한 후 재차 흡착실험을 행한 결과, 역시 매우 높은 흡착효율을 나타냈다. 따라서 Al-층간가교 점토의 인산 이온 흡착에 대한 재활용의 가능성이 큰 것으로 나타났다

The hydroxyapatite(HAp) for the present study was prepared with the wastewater sludge from semiconductor fabrication process and it was crystallized in an electric furnace for 30 min at 900℃. The adsorption characteristics of HAp for phosphate ion in aqueous solution has been investigated. The adsorbed ratio of phosphate ion for HAp were investigated according to the reaction time, amount of HAp, concentration of standard solution, pH of solution, and influence of concemitant ions. The amount of adsorbed phosphate ion decreased with the increase of pH due to the mutual electrostatic repulsion between adsorbed phosphate ions and competitive adsorption between phosphate ion and OH- ion in aqueous solution. The maxium amount of the adsorption equilibrium for phosphate ion was about 24 mg/g of HAp. The HAp would likely to be a possible adsorbent for the removal of phosphate ion in the waste water.