Changes in Soil pH and Exchangeable Acidity of Selected Parent Materials as Influenced by Amendments in South East of Nigeria

Soil chemical degradation caused by acidity is a serious constraint to food production in most parts of the Tropics. It was in the bid to proffer solution to this that the present study was conceived. Anincubation study was conducted at the laboratory of Soil Science and Meteorology Department of Michael Okpara University of Agriculture Umudike. The aim was to ascertain the effect of amendments namely: Control (no amendment), Biochar, Ash, Lime, Biochar + Poultry Manure, Ash + Poultry Manure and Lime + Poultry Manure, on soil pH and exchangeable acidity of Sandstone, Shale and Alluvium. The rate of application was 1.43 g for the sole amendments and 0.72 g each for the combined amendments to give an equivalent of 2 t/ha. They were applied to 100 g of the soil and replicated three times in a Completely Randomized Design. The incubation study lasted for eighty-four days, the pH and exchangeable acidity were determined at fourteen days intervals. The result obtained revealed that all the treatments increased the soil pH and decreased the exchangeable acidity over the control. In all parent materials, applied Lime and Lime + Pm significantly (p < 0.05) gave the highest pH of 6.6, 6.9 and 7.2 for Shale, Sandstone and Alluvium respectively on the 28th day of incubation which, was the time, the maximum pH value was attained. Biochar and Biochar + Pm were considered the appropriate amendments because the pH values they gave were towards neutral, unlike that of Lime and Lime + Pm that were towards alkaline. It is recommended that field trial of this work is conducted.

Liming and Fertilizer Potentials of Some Underutilized Plant Materials in Southwestern Nigeria

Soil acidification and phosphorus deficiency are a major constraint to crop production in tropical soils. Use of conventional liming materials is associated with some limitations viz： inability to solely improve nitrogen and available phosphorus in soils, loss of soil organic carbon and soil aggregate stability. Liming and fertilizer potentials of leaves from three plant materials （Tithonia diversifolia （TL）, Imperata cylindrica （SG） and Gliricidia sepium （GL）） widely growing in Ogbomoso, southwest Nigeria, were tested under incubation condition. Each of the plant material was applied at.the rate of 10 t·hm-2 with and without 50% concentration of NPK 15 ： 15 ： 15-urea mix in 500 g acidic soiL Sole lime applied at 1 t·hm-2, sole NPK 15 ： 15 ： 15 applied at 60 kg·hm2 mixed with urea at 60 kg N· hm2 and an unamended soil were compared in completely randomized design in three replicates. The treated soils were incubated for 12 weeks. Thereafter, maize seeds were raised in each pot for a period of 3 weeks. Data coUected were subjected to analysis of variance. Regression analysis was used to predict contributions of increased soil pH in plant material treated soils to exchangeable A1, H, dry root weight of maize and available phosphorus. Results indicated that sole plant materials were the order SG〉TL〉GL significantly （P〈0.05） reduced exchangeable acidity compared to unamended and sole NPK. Sole NPK had the highest exchangeable acidity （4.7 cmol·kg-1） compared to unamended soil （3.3 cmol·kg-1） and sole lime （2.7 cmol·kg-1）. Application of sole Tithonia diversifolia increased available phosphorus by 214% and 97% compared to unamended and sole NPK treated soils respectively. Sole plant materials increased maize root weight by 33% compared to sole NPK. Increasing soil pH at harvesting in plant material treated soils significantly reduced exchangeable H and A1. Soil pH was responsible for up to 33% and 53% reductions in exchangeable Al and H, respectively. This culminated into up to 22% increases in dry root weight of maize seedling. Present results showed ability of the plant materials tested to ameliorate soil acidity and improved soil available phosphorus. The plant materials should be explored for using as green manure and composting feedstock. It will go a long way to reduce high dosage use of conventional liming and fertilizer materials on acidic nutrient degraded soils.

Modified silicon carbide whisker reinforced polybenzimidazole used for high temperature proton exchange membrane

Polybenzimidazole containing ether bond（OPBI） was reinforced with silicon carbide whisker（m Si C） modified by 3-aminopropyltriethoxysilane（KH550）, and then doped with phosphoric acid（PA） to obtain OPBI/m Si C/PA membranes. These OPBI/m Si C/PA membranes have excellent mechanical strength and oxidative stability and can be used for high temperature proton exchange membrane（HT-PEM）. The tensile strength of OPBI/m Si C/PA membranes ranges from 27.3 to 36.8 MPa, and it increases at first and then decreases with the increase of m Si C content. The high m Si C content and PA doping level contribute to improving the proton conductivity of membranes. The proton conductivity of PBI/m Si C-10/PA membrane is 27.1 m S cm-1 at 170℃ without humidity, with an increase of 55.7% compared with that of OPBI/PA membrane. These excellent properties make OPBI/m Si C/PA membranes promising membrane materials for HT-PEM applications.

Thin-Layer Chromatographic Separation of Amino Acid Enantiomers using Ligand Exchange

Silica gel thin-layer plates covered with L-arginine and copper acetate were used for the separation of amino acid enantiomers, The chromatographic selectivity and the effects of plate different preparation methods, sample molecular structure and solvent compositions on resolution performance were also discussed.

USE OF CATION EXCHANGE RESIN IN SYNTHESIS OF N-SUBSTITUTED-1-AMINOALKANEPHOSPHONATE AND-PHOSPHINIC ACIDS

Strongly acidic cation exchange resin(1x1,H form)has been successfully used as a catalyst in synthesis of diphenyl N-benzyloxycarbonyl-1-aminobenzylphosphonate, N-benzyloxycarbonyl-1-aminobenzylphenylphosphinic acid and N-p-tolylsulfonyl-1-aminobenzyl phenylphosphinic acid in high yields.

Sorption of tylosin and sulfamethazine on solid humic acid

Tylosin（TYL） and sulfamethazine（SMT） are ionizable and polar antimicrobial compounds,which have seeped into the environment in substantial amounts via fertilizing land with manure or sewage. Sorption of TYL and SMT onto humic acid（HA） may affect their environmental fate. In this study, the sorption of TYL and SMT on HA at different conditions（pH, ionic strength） was investigated. All sorption isotherms fitted well to the Henry and Freundlich models and they were highly nonlinear with values of n between 0.5 and 0.8, which suggested that the HA had high heterogeneity. The sorption of TYL and SMT on HA decreased with increasing p H（2.0–7.5）, implying that the primary sorption mechanism could be due to cation exchange interactions between TYL~＋/SMT~＋ species and the functional groups of HA.Increasing ionic strength resulted in a considerable reduction in the K_d values of TYL and SMT,hinting that interactions between H bonds and π–π EDA might be an important factor in the sorption of TYL and SMT on HA. Results of Fourier transform infrared（FT-IR） and ~13C-nuclear magnetic resonance（NMR） analysis further demonstrated that carboxyl groups and O-alkyl structures in the HA could interact with TYL and SMT via ionic interactions and H bonds,respectively. Overall, this work gives new insights into the mechanisms of sorption of TYL and SMT on HA and hence aids us in assessing the environmental risk of TYL and SMT under diverse conditions.

Adsorption behavior of benzenesulfonic acid by novel weakly basic anion exchange resins

Two novel weakly basic anion exchange resins（SZ-1 and SZ-2） were prepared via the reaction of macroporous chloromethylated polystyrene-divinylbenzene（Cl-PS-DVB） beads with dicyclohexylamine and piperidine, respectively. The physicochemical structures of the resulting resins were characterized using Fourier Transform Infrared Spectroscopy and pore size distribution analysis. The adsorption behavior of SZ-1 and SZ-2 for benzenesulfonic acid（BA） was evaluated, and the common commercial weakly basic anion exchanger D301 was also employed for comparison purpose. Adsorption isotherms and influence of solution p H, temperature and coexisting competitive inorganic salts（Na2SO4and Na Cl） on adsorption behavior were investigated and the optimum desorption agent was obtained.Adsorption isotherms of BA were found to be well represented by the Langmuir model.Thermodynamic parameters involving ΔH, ΔG and ΔS were also calculated and the results indicate that adsorption is an exothermic and spontaneous process. Enhanced selectivity of BA sorption over sulfate on the two novel resins was observed by comparison with the commercial anion exchanger D301. The fact that the tested resins loaded with BA can be efficiently regenerated by Na Cl solution indicates the reversible sorption process. From a mechanistic viewpoint, this observation clearly suggests that electrostatic interaction is the predominant adsorption mechanism. Furthermore, results of column tests show that SZ-1possesses a better adsorption property than D301, which reinforces the feasibility of SZ-1for potential industrial application.

Highly active iridium catalyst for hydrogen production from formic acid

Formic acid（FA） dehydrogenation has attracted a lot of attentions since it is a convenient method for H_2 production. In this work, we designed a self-supporting fuel cell system, in which H_2 from FA is supplied into the fuel cell, and the exhaust heat from the fuel cell supported the FA dehydrogenation. In order to realize the system, we synthesized a highly active and selective homogeneous catalyst Ir Cp＊Cl_2 bpym for FA dehydrogenation. The turnover frequency（TOF） of the catalyst for FA dehydrogenation is as high as7150 h^（-1）at 50°C, and is up to 144,000 h^（-1）at 90°C. The catalyst also shows excellent catalytic stability for FA dehydrogenation after several cycles of test. The conversion ratio of FA can achieve 93.2%, and no carbon monoxide is detected in the evolved gas. Therefore, the evolved gas could be applied in the proton exchange membrane fuel cell（PEMFC） directly. This is a potential technology for hydrogen storage and generation. The power density of the PEMFC driven by the evolved gas could approximate to that using pure hydrogen.