Evaluation of Water from Bokro Stream for Irrigation and Its Effect on Soil

This study focused on evaluating the water quality of the Bokro stream for its suitability for irrigation purposes. Among the water quality parameters examined were pH, total dissolved solids, conductivity, dissolved oxygen, hardness, major ions and concentration of some trace metals. The results revealed that most of the parameters examined were below the FAO limits for irrigation water. The results also indicated that nutrient concentrations (Sulphate, Nitrate-Nitrogen and Phosphate-Phosphorus) from the stream were far below the usual ranges in irrigation water. Based on values calculated for Sodium Adsorption Ratio and electrical conductivity, the water source could be described as possessing low salinity hazard and therefore no permeability problems are expected for the soils. In addition, human activities along the banks of the stream and inflow of untreated domestic sewage from communities in the catchment area of the stream were found to have great impact on the quality of water from the stream. Water from the stream will have no adverse effect on the soil when it is use for irrigation.Keywords: Bokro stream, Irrigation, Salinity hazard, Self purification, Waste wate

REACTION MECHANISM OF DESFERRIOXAMINE-B WITH Al AND Fe MINERALS CONTAINING PHOSPHORUS

植物從土壤中攝取養分受到植物根系與土壤之物理、生物化學性質交互作用的複雜過程影響。單子葉禾本科植物的根分泌可鉗合三價鐵且對鐵親和力高的載鐵物質 (phytosiderophores, PSs) 來溶解土壤中的鐵，進而影響磷等其他營養元素在土壤中的移動。本研究目的為：探討載鐵物質之一的去鐵胺 (desferrioxamine-B, DFO-B) 與含鐵、鋁或磷礦物 (紅磷鐵礦 (strengite, FePO4∙2H2O) 、磷酸鋁石 (variscite, AlPO4∙2H2O)) 與已吸附磷的針鐵礦 (goethite, α-FeOOH)、水鋁礦 (gibbsite, α-Al(OH)3)、赤鐵礦 (hematite, α-Fe2O3) 交互作用下礦物表面溶出的情形，進而來瞭解載鐵物質在植物吸收磷可能扮演的角色。實驗結果顯示：擬一級速率方程式適合用於說明DFO-B促進含鐵、鋁或磷礦物的溶解情形，其中溶解的速率常數與DFO-B被吸附的量有相關性。在 pH 4 下，DFO-B隨著針鐵礦、水鋁礦與赤鐵礦表面所吸附磷含量的增加而加速礦物的溶解速率。然而，在 pH 9下，礦物表面磷吸附量的增加卻抑制礦物表面的溶出，可能是因 pH 9 環境下，磷酸根在礦物表面形成了較穩定的結構，使DFO-B不易溶解礦物表面。根據 Arrhenius 方程式，在不同溫度與 pH 下，DFO-B與不同礦物反應之活化能 (activation energies, Ea) 也顯示：在 pH 9 下的反應之活化能高於 pH 4 下的活化能，表示磷酸根與礦物表面在 pH 9 下形成了DFO-B難以鉗合的形式，進而抑制了礦物表面的溶解。針對含鐵磷或鋁磷的礦物研究發現：DFO-B的存在促進紅磷鐵礦與磷酸鋁石溶解的現象。其中，因為磷酸鋁石表面吸附較多的DFO-B，造成磷酸鋁石溶解速率較紅磷鐵礦溶解速率快。Nutrient uptake of plants from soil is a complex process determined by the interactions of the plant roots with the soil and the combination of physical and biochemical properties of the soil. The roots of graminaceous monocots secrete phytosiderophores (PSs), which are chelating agents with a high affinity for Fe(III), to dissolve Fe(III) in soil. The release of PSs can potentially mobilize nutrients, such as P, associated with Fe in soil. To understand the potential role of PSs in regulating the P acquisition of plants, this study investigated the interactions of desferrioxamine-B (DFO-B) siderophore with some major Fe, Al and P - containing minerals, including strengite (FePO4∙2H2O), variscite (AlPO4∙2H2O), and phosphate-loaded goethite (α-FeOOH), gibbsite (α-Al(OH)3) and hematite (α-Fe2O3). The pseudo-first-order rate constant was determined for the DFO-B – promoted dissolution of each mineral and subsequently normalized to the corresponding amount of adsorbed siderophore to calculate the mass-normalized dissolution rate. Apparent activation energies (Ea) were calculated from the mass-normalized dissolution rates of each mineral obtained at different temperatures using the Arrhenius equation. Increasing the loading of adsorbed P on all three oxides (i.e., goethite, hematite and gibbsite) resulted in an increase in the dissolution rates of the minerals but a decrease in dissolution rates at pH 9. The rate inhibition at pH 9 is attributed to the presence of binuclear surface complexes, in which much more energy is required to remove simultaneously two center atoms from the crystalline lattice than it is to remove solely one center (i.e. in the case of mononuclear complexes at pH 4). Higher Ea values at pH 9 than at pH 4, supports our hypothesis that the existence of stronger adsorbed phosphate complexes hinder the smooth release of the metal-ion-center. DFO-B -promoted dissolution of strengite and variscite studies show that dissolution was enhanced in the presence of DFO-B. Higher dissolution rates for variscite than strengite is attributed to the higher adsorbed concentrations of DFO-B on variscite than on strengite.摘要 i ABSTRACT ii ACKNOWLEDGMENTS iv TABLE OF CONTENTS vi LIST OF TABLES ix LIST OF FIGURES xiii 1. INTRODUCTION 1 1.1 Background 1 1.2 Objectives 5 2. LITERATURE REVIEW 7 2.1 Metal Oxides in Soil 7 2.2 The Structures of the Applied Minerals 9 2.2.1 Goethite 9 2.2.2 Hematite 10 2.2.3 Gibbsite 12 2.2.4 Strengite and Variscite 13 2.3 Phosphate 14 2.3.1 Uncomplexed Phosphate in Aqueous Solution 15 2.3.2 Adsorption of Phosphate on Metal Oxides 16 2.3.3 pH Dependency 18 2.4 Siderophores 19 2.4.1 Chemistry of Siderophores 23 2.5 Mineral Dissolution 26 2.5.1 Rate Laws 27 2.5.2 Temperature Dependence 28 3. MATERIALS AND METHODS 31 3.1 Chemicals 31 3.2 Mineral phases Synthesis/ Mineralogical Samples synthesis 31 3.2.1 Goethite (α-FeOOH) 31 3.2.2 Hematite (α–Fe2O3) 32 3.2.3 Variscite (AlPO4 ‧ 2H2O) 32 3.2.4 Strengite (FePO4‧2H2O) 33 3.2.5 Gibbsite [γ-Al (OH)3] 33 3.3 X-ray Diffraction Analyses 34 3.4 Adsorption Experiments 34 3.4.1 Maximum Phosphorus Adsorption Capacities of Minerals 34 3.4.2 Adsorption of DFO-B on Mineral Surfaces 38 3.5 Steady-State Ligand-promoted Dissolution of Minerals in the Presence of DFO-B 38 3.6 Analysis Methods 39 4. RESULTS 41 4.1 Mineral Characterization 41 4.2 Adsorption of Phosphates on Oxides 43 4.3 Dissolution Kinetics 46 4.4 Dissolution of Strengite and Variscite 60 4.5 Phosphate Desorption Kinetics 66 4.6 Effect of Adsorbed Phosphate on Dissolution 72 4.7 Temperature Effect 74 4.8 Temperature dependence of DFO-B - promoted dissolution of strengite and variscite. 88 5. DISCUSSION 90 5.1 Phosphate Adsorption 90 5.2 DFO-B Adsorption and –promoted Dissolution 91 5.3 pH-Dependence and the Influence of Phosphate 92 5.4 Dissolution of Strengite and Variscite. 98 5.5 Temperature Dependence of Dissolution 99 6. CONCLUSIONS 108 REFERENCES 109 APPENDIX 13

A comparative study of hexacyanoferrate-based Prussian blue analogue nanocrystals for catalytic reduction of 4-nitrophenol to 4-aminophenol

Catalytic reduction of 4-nitrophenol (4-NP) represents a useful method of converting 4-NP into a more environmentally friendly product, 4-aminophenol (4-AP). Prussian blue (PB) (Fe3[Fe(CN)6]2) and its Prussian blue Analogues (PBAs) (MII[Fe(CN)6] PBAs (MII = Mn, Co, Ni, and Zn) exhibit hierarchical porous structures, and electrochemical characteristics, making PBAs promising catalysts for 4-NP reduction. Nevertheless, very few literatures report the reduction of 4-NP to 4-AP employing PBAs, and no studies have been ever conducted to evaluate the effects of different MII species of [Fe(CN)6]-based PBAs on the catalytic conversion of 4-NP to 4-AP. Herein, we examine the catalytic reductive performance of various MII[Fe(CN)6] PBAs (MII = Co, Fe, Mn, Ni, and Zn), in the presence of sodium borohydride (NaBH4), on 4-NP reduction to 4-AP. The catalytic activity of PBAs for 4-NP reduction was in the order CoFeCN > NiFeCN > FeFeCN > MnFeCN > ZnFeCN. The corresponding activation energies are determined as 32, 43, 46, 47, and 54 kJ/mol for CoFeCN, NiFeCN, MnFeCN, FeFeCN and ZnFeCN, respectively. Especially, CoFeCN shows the highest catalytic activity with a rate constant of 0.457 min−1 and a calculated turnover frequency of 6.3 × 10−3 s−1, which are higher than many reported noble metal catalysts because of its high surface area and catalytic activities towards hydrogen generation and hydrogenation. CoFeCN (and NiFeCN) also exhibit excellent reusabilities even after 6 consecutive reduction experiments. These findings demonstrate that PBAs, such as CoFeCN and NiFeCN, are highly advantageous catalysts for reduction of 4-NP and would be promising for reducing other nitro-aromatic compounds

Copper hexacyanoferrate nanocrystal as a highly efficient non-noble metal catalyst for reduction of 4-nitrophenol in water

As Prussian Blue analogues (PBAs) represent one of the most classical families of coordination compounds and exhibit versatile catalytic activities, PBAs have been considered as useful heterogeneous catalysts for reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). Nevertheless, while Cu has been a well-proven transition metal for 4-NP reduction, especially, due to their ability to attain pronounced conversions of reactants under mild conditions, environmental friendliness and great stability. Nevertheless, while Cu has been a well-proven transition metal for 4-NP reduction, Cu-based PBA has never been developed and thoroughly investigated for 4-NP reduction. Thus, in this study, copper hexacyanoferrate, CuII3[Fe(CN)6]2 (CuFeCN) is particularly synthesized and proposed for the first time as a catalyst for reduction of 4-NP in the presence of NaBH4. CuFeCN exhibits a very high catalytic activity towards reduction of 4-NP to 4-AP with 100% conversion within 4 min. The activity factor (AF) at room temperature, 8057.14 s−1 g−1, is between 1 and 2 orders higher than all other MFeCN Prussian blue analogues (M = Co, Fe, Ni, Zn, and Mn). In addition, CuFeCN shows excellent reusability to achieve 100% conversion of 4-NP to 4-AP with highly stable rate constants over successive 7 cycles. The activation energy (Ea) and turn over frequency (TOF) for the reduction of 4-NP to 4-AP catalyzed by CuFeCN system are determined as 24.6 kJ mol−1 and 36.93 min−1, respectively, which are both significantly more superior than most of reported catalysts in literatures. These advantageous properties make CuFeCN ideal to be developed into a promising catalyst for elimination of nitroaromatic contaminants in water

Cobalt Oxides with Various 3D Nanostructured Morphologies for Catalytic Reduction of 4-Nitrophenol: A Comparative Study

Catalytic reduction processes represent a promising approach to treat the toxic nitro-aromatic pollutant, 4-nitrophenol (4-NP), via converting 4-NP to 4-aminophenol (4-AP). Many efforts have been invested into developing non-precious metal oxides for the conversion of 4-NP to 4-AP. As Co3O4 is validated as a useful non-precious metal catalyst for 4-NP reduction, it is crucial to probe into the relationship of morphology-property-reactivity of Co3O4 catalysts for optimizing design of Co3O4 for 4-NP reduction. Thus, the catalytic activity of Co3O4 for 4-NP is particularly investigated in this study through examining 3-dimensional (3D) Co3O4 catalysts (3DCoOs) with different nanostructured morphologies, including the conical-Co3O4 (CCO), stacked-Co3O4 (SCO), needled-Co3O4 (NCO) and floral-Co3O4 (FCO), for 4-NP reduction. A remarkably enhanced activity in the reduction of 4-NP is realized over all 3DCoOs than commercial Co3O4 catalysts. In particular, CCO shows the highest catalytic performance (k =0.6882 min-1 and Ea = 37.4 kJ mol-1), whereas FCO exhibits the least catalytic activity, with k =0.4709 min-1 and Ea = 47.1 kJ mol-1. These values are far more superior than those obtained by the commercial Co3O4 and the reported catalysts. All four 3DCoOs also show stable recyclability with complete 4-NP reduction over five successive cycles. These results and findings suggest that 3DCoOs are certainly advantageous Co-based catalysts for 4-NP reduction, and, through this study, the relationship between morphology, property and reactivity would be correlated to offer useful insights to design and apply 3D nanostructured Co3O4 catalysts for 4-NP reduction

ZIF-67 supported on marcoscale resin as an efficient and convenient heterogeneous catalyst for Oxone activation

While metal organic frameworks (MOFs) are promising catalysts for aqueous chemical oxidation, MOFs are typically prepared to be nanoscale and thus less practical for solution-based reactions. Although a few attempts have developed substrate-supported MOFs, many of them are still small and none of them are developed for sulfate-radical based chemical oxidation. However, there is still an urgent demand for developing substrate-supported MOFs which are catalytically effective, conveniently prepared, and simply recyclable. In this study, a macrosphere-supported MOF is successfully fabricated using ion exchange resins as readily available, stable and functionalized macrospheres. Via equilibrating resins with 2-MIM and cobalt ions sequentially, a cobalt-based MOF, zeolitic imidazolate framework-67 (ZIF-67) nanocrystal, is grown on the resin surface via self-assembly. The resulting composite of ZIF "at" resin (abbreviated as ZIF@R) can preserve porous structures and metal coordination of ZIF-67, and also convenient features of resins, making it an advantageous heterogeneous catalyst for activating Oxone in water. As Rhodamine B (RhB) decolorization is employed as a model test for evaluating Oxone activation, ZIF@R is confirmed not only to activate Oxone for full decolorization of RhB but also to exhibit a much higher catalytic activity than Co3O4, the most typical catalyst for Oxone. ZIF@R could be also re-used to activate Oxone for RhB decolorization without activity loss. These results indicate that ZIF@R is a conveniently prepared and highly effective and stable macroscale catalyst for aqueous chemical oxidation reactions

Elimination of bromate from water using aluminum beverage cans via catalytic reduction and adsorption

While zero valent aluminum (ZVAl) is a promising reductant for eliminating bromate from water, ZVAl is typically obtained from reagent grade aluminum. As used aluminum beverage can is the most common aluminum waste, it can be conveniently used to prepare ZVAl. Thus, in this study aluminum beverage cans are employed for the first time as a plentiful and easily accessible aluminum source to afford ZVAl for eliminating bromate from water. As aluminum is easily oxidized to form aluminum oxide, aluminum can pieces (ACPs) are pre-treated with HCl for removing the oxide layer to afford ZVAl. While non-acid-treated ACP is ineffective to remove bromate, the acid-treated ACP successfully eliminates bromate from water completely. Bromate elimination by ACP is attributed to reduction of bromate to bromide by the reactive sites of ACP and adsorption of bromate to the surface of ACP. Bromate elimination by ACP also proceeds much faster at higher temperatures and low pH values, while the alkaline condition causes serious negative effects on bromate elimination. Besides, oxalic acid is found to facilitate bromate elimination not only on the kinetics but also reduction to bromide because the passivation layer is suppressed in the presence of oxalic acid. ACP could also be reused and the acid-washing regeneration could enable used ACP to restore its reactive sites for bromate elimination. This study successfully demonstrates the valorization of aluminum beverage cans for mitigating the toxic bromate and the findings here provide useful information and insights to develop aluminum beverage cans for controlling pollutants in water

Prussian Blue analogue supported on sulfur-doped carbon nitride as an enhanced heterogeneous catalyst for activating peroxymonosulfate

While Prussian Blue (PB) analogues are attractive catalysts for activating peroxymonosulfate (PMS), PB analogues are very small and thus difficult for recovery. Immobilizing PB particles onto graphene is a useful technique which facilitates recovery and also enhances catalytic activities. As doping graphene with sulfur/nitrogen (S/N) increases its electro-conductivity and active sites, the composite of PB and S/N-doped graphene should enhance PMS activation. Thus, this study aims to fabricate such a composite. Unlike conventional S/N-doped graphene prepared via post-modifications, trithiocyanuric acid is used as a precursor, which is converted to S-doped graphitic carbon nitride (SCN). The composite of PB and SCN (PBSCN) is then fabricated by growing a cobalt-based PB analogue on SCN. The resulting PBSCN preserves the crystalline structures, textural properties and catalytic sites of PB and SCN. As degradation of Acid Red 27 (AR) is used as a model reaction, PBSCN exhibits a higher catalytic activity than PB and SCN individually, as well as Co3O4 to activate PMS for AR degradation possibly because SCN may facilitate electron transfer and enhance catalytic activities of PB. PBSCN also remains effective and re-usable over several cycles for AR degradation. These features indicate that PBSCN is a promising catalyst for activating PMS and the fabrication technique demonstrated here can be employed to prepare composites of various PB analogues and carbon nitride to exhibit enhanced catalytic activities

One-step synthesized 3D-structured MOF foam for efficient and convenient catalytic reduction of nitrogen-containing aromatic compounds

Metal Organic Frameworks (MOFs) receive increasing attention for 4-nitrophenol (4-NP) reduction; however the existing studies of using MOFs for 4-NP reduction all involve with noble metals. Moreover, the reported MOFs are very fine powders which are inconvenient for realistic implementation. Thus, the present study proposes to develop a MOF foam which exhibits macroscale features of foam and microscale functionalities of MOFs. Specifically, a Cu foam is selected as the macroporous substrate which serves as a porous support and the metal source for synthesizing Cu-based MOF, HKUST-1, via an one-step electrochemical method. The resulting HKUST-1 foam can act as a convenient catalyst for reduction of 4-NP to 4-AP in either batch-type or flow-thru-type reactions. The corresponding activation energy (Ea) of 4-NP reduction (43.3 kJ/mol) is also significantly lower than Ea values of reported catalysts, including noble metal catalysts, whereas the corresponding TOF (48.3 min−1) is higher than many other catalysts. HKUST-1 foam can also efficiently catalyze reduction of methylene blue (MB) to fully decolorize its color. In addition, HKUST-1 foam could be reused over multi-cycles and retain its activity for reduction of 4-NP and MB. These features validate that HKUST-1 foam is a practical, convenient, and reusable catalyst for reduction of 4-NP