Titration Alkalinity Research Articles

Measuring enhanced weathering: inorganic carbon-based approaches may be required to complement cation-based approaches

The removal of atmospheric carbon dioxide (CO2) is now essential to meet net zero goals and limit the impacts of climate change. Enhanced weathering is a method of sequestering CO2 that involves the distribution of finely ground silicate rocks over agricultural land. The weathering of these silicate rocks releases cations into solution which can balance dissolved inorganic carbon, effectively removing CO2 from the atmosphere. Despite being a promising method of carbon dioxide removal (CDR), enhanced weathering has been limited by uncertainty surrounding the measurement of CO2 sequestration. This study compares current measurement approaches that focus on quantifying inorganic carbon and cations within the soil and leachate. Cation-based calculations of CDR were compared to inorganic carbon-based calculations of CDR and soil results were compared to leachate results. The recovery rate of cations in the soil fraction was also tested. Three different ground silicate minerals/rocks – basalt, olivine and wollastonite, were mixed with two different soils and were allowed to weather over 16 weeks in 320 pots with and without plants under different watering regimes and the application of an acidifying fertiliser. Soil and leachate samples were analysed for cations by ICP-OES and inorganic carbon by direct CO2 analysis after acidification and total alkalinity titration (in leachate only). The results indicate that the soil retains most enhanced weathering products through the cation exchange reactions. CDR estimated by cations is often greater than CDR estimated by inorganic carbon. Measurement approaches to estimate cations are susceptible to incomplete or improper accounting through the under-extraction of cations stored within the soil-exchangeable pool, the activity of non-carbonic acids and CO2 outgassing. Inorganic carbon-based measurements, including direct inorganic carbon and total alkalinity analysis, are also complicated by the potential for CO2 loss through carbonate precipitation and re-equilibration. Therefore, inorganic carbon-based approaches and cation-based approaches should be reconciled to validate the estimation of CDR. The inorganic carbon-based estimation of CDR in leachate should equal the cation-based estimation of CDR in leachate—which will be achieved after quantification or estimation of the natural mechanisms that affect each approach. These findings will support the development of accurate measurement processes for enhanced weathering.

Rh proteins and H+ transporters involved in ammonia excretion in Amur Ide (Leuciscus waleckii) under high alkali exposure

High alkaline environment can lead to respiratory alkalosis and ammonia toxification to freshwater fish. However, the Amur ide (Leuciscus waleckii), which inhabits an extremely alkaline lake in China with titratable alkalinity up to 53.57 mM (pH 9.6) has developed special physiological and molecular mechanisms to adapt to such an environment. Nevertheless, how the Amur ide can maintain acid-base balance and perform ammonia detoxification effectively remains unclear. Therefore, this study was designed to study the ammonia excretion rate (Tamm), total nitrogen accumulation in blood and tissues, including identification, expression, and localization of ammonia-related transporters in gills of both the alkali and freshwater forms of the Amur ide. The results showed that the freshwater form Amur ide does not have a perfect ammonia excretion mechanism exposed to high-alkaline condition. Nevertheless, the alkali form of Amur ide was able to excrete ammonia better than freshwater from Amur ide, which was facilitated by the ionocytes transporters (Rhbg, Rhcg1, Na+/H+ exchanger 2 (NHE2), and V-type H+ ATPase (VHA)) in the gills. Converting ammonia into urea served as an ammonia detoxication strategy to reduced endogenous ammonia accumulation under high-alkaline environment.

Combining lime and organic amendments based on titratable alkalinity for efficient amelioration of acidic soils

Abstract. Ameliorating soil acidity using a combination of lime and organic amendments (OAs) can be an alternative to lime alone, but determining the appropriate OA rates can be difficult. We developed a new method for calculating the combined application rate of lime and OAs (wheat straw, faba bean straw, blended poultry litter, biochar, and compost) that is based on the titratable alkalinity of OAs and the equilibrium lime buffer capacity (LBCeq) of acidic soils. The effect of calculated soil amendment rates on soil pH was validated at soil water contents of 60 %, 100 %, and 150 % of field capacity (FC). The soil used to develop and validate the method was a sandy loam with a soil pH in deionised water (pHW) of 4.84 and a soil pH in 0.01 M CaCl2 solution (pHCa) of 4.21. The LBCeq of the soil was 1657 mg CaCO3 kg−1 pH−1 (where “CaCO3 kg−1 pH−1” denotes the amount of lime required to raise the pH of 1 kg of soil by one unit). The titratable alkalinity of the OAs ranged from 11.7 cmol Heq+ kg−1 for wheat straw to 357 cmol Heq+ kg−1 for compost. At 60 % FC, faba bean and wheat straw amendment increased the soil pHW to 6.48 and 6.42, respectively, but lower pH values were reached in soil amended with less biodegradable or resistant OAs (ROAs) (i.e. blended poultry litter, biochar, and compost). At 150 % FC, the two straws increased the soil pHW to only 5.93 and 5.75, respectively, possibly due to slower decomposition under submerged conditions, resulting in limited alkalinity production, whereas amendment with ROAs produced pHW values close to 6.5. With an increasing lime-equivalent value (LEV) of the OA, from 5.8 g CaCO3 kg−1 (wheat straw) to 179 g CaCO3 kg−1 (compost), the lime requirement to reach pHW 6.5 in lime–OA combinations decreased from 2.72 to 0.09 g CaCO3 kg−1. The developed method was shown to be effective in determining the appropriate rates of OAs (with or without additional lime) for the management of acidic sandy loam soils in this study and highlights the importance of the soil water content with respect to its acid-neutralising effect.

A differential titration method for determining the dissociation characteristics of natural organic acids in the coastal zone

Characterizing the concentrations and equilibrium characteristics of organic acid/base pairs is essential for quantifying CO2-system components and their behaviors and interactions in organic-rich coastal environments. Relatively few studies have been devoted to characterization of titratable organics, and their contributions to total alkalinity are frequently implicitly or explicitly considered negligible. In this work, novel potentiometric titration procedures were developed to quantify the concentrations and dissociation constants of river-derived titratable organics and thereby their alkalinity (Org-Alk) contributions to the total alkalinity (TA) of coastal seawater. The overall approach was to compare the titration properties of two paired solutions of identical salinity (S ≈ 5): (a) a sample of “estuarine” water formulated as a mixture of organic-rich river water plus open-ocean seawater and (b) an organics-free “baseline” approximation of that estuarine water, formulated as a mixture of dilute aqueous sodium chloride plus open-ocean seawater. Acid was incrementally added to both solutions, and the resulting two titration curves were then compared to provide direct visualization and quantification of the contributions of organics to TA. In other words, at any given pH, the difference in acid added to the two solutions (with a small correction for silicate alkalinity) indicates acid uptake by titratable organics in the estuarine sample. This procedure was performed for four replicate samples at 15, 25, and 35 °C. Our titrations indicated the presence of three types of titratable organics. The dominant type had a concentration of approximately 200 μmol∙kg−1 and a well-defined dissociation constant (pK) that did not vary with temperature: pKOrg2(average) = 6.33 ± 0.01. The second type had a concentration of approximately 110 μmol∙kg−1 and a moderately well-defined and high pK: 8.56 ≤ pKOrg3 ≤ 9.32. The third type had a concentration of approximately 40 μmol∙kg−1 and a low, poorly defined pK: 4.1 ≤ pKOrg1 ≤ 6.1. Inference of this third type was required to eliminate systematic residuals that were otherwise present in our fitted titration data (residuals = direct observations – model predictions). These data allow for a summation of TA contributions from organic constituents that may contribute (especially in coastal waters) but are typically uncharacterized. Such data are required for rigorous CO2-system models that rely on inputs of the commonly used data pair of TA and dissolved inorganic carbon (DIC). Studies of CO2 system behavior in the coastal zone clearly require two types of alkalinity titrations – one that includes a summation of inorganic and organic components (i.e., conventional titrations), and a second CO2-free titration in which the concentrations and pK characteristics of organic acids are quantified.

Preparation of inorganic nanocomposite coagulant and its application in oilfield sewage treatment

Carbon nanotubes (CNTs), as a new type of carbon material with complete molecular structure, have great application potential in the field of nanocomposites. In this study, carbon nanotubes were first surface modified to give them good hydrophilicity. Subsequently, the nanocomposite coagulant (PASS-T) with different modified CNTs (m-CNTs) contents was prepared by alkaline titration method. The CNT, m-CNT, PASS and PASS-T were characterized by FTIR, XRD and XRF. Then the coagulant was applied to oily sewage, and the coagulation results showed that the PASS-T (0.1%) had the best oil reduction rate (92%) and turbidity reduction rate (97%). Appropriate addition of m-CNT can increase the local concentration of coagulant at the molecular level, making the flocs of oily sewage larger. It can be found by SEM that PASS-T produces large and knotted flocs in oily sewage. Finally, the residual turbidity and oil removal rate of the different coagulants were statistically analyzed.

Estimation method for carbonate in natural alkaline soda lake-waters

Natural, inland alkaline soda waters form a particular type of saline waters, characterized by a permanent alkaline chemical property. In many cases only the total alkalinity by methyl-orange titration is reported, without phenolphthalein titration. Therefore, a reliable estimation of carbonates from total alkalinity is essential for a precise scientific chemical classification. The concentration of bicarbonate [HCO3‒] can be reliably estimated in waters using the Advanced Speciation Method (ASM) if methyl-orange total alkalinity titration and pH data are available, while the concentration of carbonate [CO32‒] is not reliably estimated by the ASM when interfering factors with acid/base properties (e.g., phosphate, silicate, ammonia, etc.) are present in significant concentrations in natural waters. Therefore, here I present and prove an experimental polynomial function for carbonate estimation with the following equation based on the concentration of bicarbonate:[CO32‒] = -2.878E-7 ± 5.438E-8 × [HCO3‒]2 + 0.069±0.003 × [HCO3‒]This Boros's carbonate estimation method can contribute to a more efficient evaluation of field water samples with several analytical difficulties.•Bicarbonate can be reliably estimated using the Advanced Speciation Method (ASM).•Estimation of the carbonate concentration using ASM in the presence of interfering acid/base factors in alkaline waters.•Experimental polynomial function for reliable carbonate estimation in alkaline soda waters.

Influence of Incorporating Decomposition Agent in Oil Rapeseed Return Practice on Fungal Community, Soil Fertility and the Cotton Yield

Oil rapeseed biomass return plays a critical part in agricultural crop production. It is therefore necessary to widen the knowledge on how the microbial community adjustments actuated by straw biomass return under the application of decomposition agent advantages the quality of soil and cotton productivity. The experiment therefore aimed at applying soil molecular (sequencing, alpha and beta diversity analysis) and chemical analysis (alkaline hydrolysis-diffusion, titration and calorimetric) techniques to study the contribution of 3 treatments (no straw return, straw return under decomposition agent and straw return under no decomposition agent) on the diversity of the fungal community, soil quality and cotton productivity. The result showed that fungal OTUs were most abundant within the straw return treatments than the no straw return treatment and this was dominated by ecologically significant genera such as Apodospora, Zopfiella, Staphylotrichum, leptogium and Trechispora. Moreover, it was shown that no straw return treatment had statistically significant lower community diversity under all the indexes as compared to the other two treatments (P <0.05). In conclusion, study therefore confirmed the beneficial contribution of oil rapeseed straw return to the biological (fungal) and physical (pH, N, P and K) quality of the soil, resulting to improved cotton yield parameters.

Low-cost automated pipetting system using a single board computer and 3D-printing

A low-cost, automated pipetting system (auto pipet) was developed to deliver microliter volumes of aqueous solutions. This system was constructed using a single board computer, 3 D-printed parts, stepper motors, and other commercially available components. The performance of the auto pipet was found to be comparable or better than manual pipetting and a commercially available liquid handling system. Inter-day, intra-day, inter-instrumental, and intra-instrumental validation studies were performed to evaluate the accuracy and precision of liquid delivery using the auto pipet. Accuracy was determined to be from 98 to 102% with the precision, represented as the relative standard deviation, to be less than 3%. The auto pipet was further evaluated by the preparation of calibration and check standards for the determination of method detection limit, accuracy, and precision for trihalomethanes using a commercially available monitoring system. The auto pipet was also used as a digital buret to perform water hardness and water alkalinity titrations with promising results.

Yogurt and molasses can alter microbial-digestive and nutritional characteristics of pomegranate leaves silage

Fewer studies in recent years have been conducted on the nutritional potential and fermentation quality of silage prepared from pomegranate leaves (PL). So, we investigated the nutritional-fermentation quality of PL before and after ensiling with or without yogurt containing mainly lactic acid-producing bacteria (Lactobacillus bulgaricus and Streptococcus thermophiles) and molasses (at two levels of 2 and 4% of dry matter) in the polyethylene microsilos for 60 days. A range of dry matter (29.1–39.1%), crude protein (3.85–4.83%), ash (5.33–8.60%), and non-fiber carbohydrates (53.2%–58.6%) contents were observed among the treatments. A significant increase in calcium, potassium, magnesium, manganese, iron, and zinc was observed in PL after ensiling compared to before ensiling (p < 0.05). The PL ensiled with 4% yogurt exhibited the highest ammonia nitrogen, lactic and acetic acids, but the lowest butyric acid among the ensiled PL (p < 0.05). The ensiling of PL without additive (control) significantly decreased potential gas production, dry matter digestibility, organic matter digestibility, total volatile fatty acids, metabolizable energy, net energy for lactation, base-buffering capacity, titratable alkalinity, and acid–base buffering capacity compared to before ensiling (p < 0.05). According to the present results, the nutritional value of PL before ensiling was higher than after ensiling. The addition of yogurt and molasses to PL at the ensiling process especially at 4% of dry matter, improved the fermentation and nutritional characteristics. In general, the addition of yogurt or molasses as two cheap and available additives is recommended to improve the digestive-fermentation parameters of PL in silo and ruminal environments.

Fluorescence labeling of mitochondria in living cells by the cationic photosensitizer ZnTM2,3PyPz, and the possible roles of redox processes and pseudobase formation in facilitating dye uptake

ABSTRACT The study of labeling selectivity and mechanisms of fluorescent organelle probes in living cells is of continuing interest in biomedical sciences. The tetracationic phthalocyanine-like ZnTM2,3PyPz photosensitizing dye induces a selective violet fluorescence in mitochondria of living HeLa cells under UV excitation that is due to co-localization of the red signal of the dye with NAD(P)H blue autofluorescence. Both red and blue signals co-localize with the green emission of the mitochondria probe, rhodamine 123. Microscopic observation of mitochondria was improved using image processing and analysis methods. High dye concentration and prolonged incubation time were required to achieve optimal mitochondrial labeling. ZnTM2,3PyPz is a highly cationic, hydrophilic dye, which makes ready entry into living cells unlikely. Redox color changes in solutions of the dye indicate that colorless products are formed by reduction. Spectroscopic studies of dye solutions showed that cycles of alkaline titration from pH 7 to 8.5 followed by acidification to pH 7 first lower, then restore the 640 nm absorption peak by approximately 90%, which can be explained by formation of pseudobases. Both reduction and pseudobase formation result in formation of less highly charged and more lipophilic (cell permeant) derivatives in equilibrium with the parent dye. Some of these are predicted to be lipophilic and therefore membrane-permeant; consequently, low concentrations of such species could be responsible for slow uptake and accumulation in mitochondria of living cells. We discuss the wider implications of such phenomena for uptake of hydrophilic fluorescent probes into living cells.

Effects of Processing Methods on the Cyanide Level of Fufu (A Manihot Species Product)

The work on the effects of processing method on the cyanide content of fufu was carried out using standard chemical procedures. The processing methods include: wet cooking and pounding, and the dry-stirred methods. The cyanide content of samples from both processing methods was determined using the alkaline titration method. The results obtained showed that the cyanide content of the wet cooked and pounded fufu was 20.52 mg/kg while that of the dry cooked and stirred sample was 18.36 mg/kg. The raw uncooked cassava paste had a cyanide level of 42.12 mg/kg while the standard WHO permissible limit for cyanide in cassava is 10 mg/kg. Processing reduces appreciably the cyanide level in cassava but the present study shows that the dry cooking with stirring is more effective than the wet cooking and pounding process in the reduction of cyanide in fufu. Thorough processing of cassava meal is emphasized to remove much of the toxic cyanide content for the safety of consumers.

Effects of Frying Time on the Concentration of Cyanide in Garri (A Fermented Cassava Product)

The study investigated the effects of frying time on the cyanide content of garri, a cassava meal commonly consumed in many parts of the world especially, Africa. Tubers of cassava were obtained from Umuna Okigwe, peeled and ground. The pulp was packed into a cotton bag, dewatered and allowed to ferment under pressure using locally fabricated mechanical press. A calculated quantity (80 g) of the semi-dried pulp, was placed in a metallic basin and placed on a fireplace and fried. 15 g each of the roasting sample were removed after 10-, 20-, 30- and 35-minutes frying intervals and subjected to alkaline titration method to determine their cyanide content. Results showed that at 10mins, 20 mins, 30 mins and 35 minutes of frying reduced the cyanide content to 19.44, 10.8, 10.8 and 9.72mg/kg respectively. It is therefore strongly recommended that the frying time of garri be maximized to effectively reduce the cyanide contents of the product.

Innovative synthesis of polytitanium chloride by electrodialysis: Identification of Ti-based hydroxyl polymers and coagulation performance

Biocompatibility of titanium (Ti) and recycling of the coagulated sludge to produce functional nanoparticles make the popularization of Ti-based coagulants highly attractive. Slow alkaline titration (SAT) method was commonly used to synthesize polytitanium coagulants, but cannot control the formation of dominant flocculation species due to the fast hydrolysis. We propose the innovative preparation of Ti-based coagulants by electrodialysis (ED) to control the directional transfer of electrons and regulate the rate of the micro-interface reaction. An efficient polytitanium chloride (PTC) was successfully prepared by ED method with TiCl4 as precursor, denoted as E-PTC. Results from electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS) proved the generation of the Ti-based hydroxyl polymers with various degrees of polymerization benefiting from the controllable migration of ions during ED process. The predominant Ti-based species changed from the small/median polymers to the large ones with increasing ED period. This was evidenced by Ti-Ferron assay that high Tib (34.35%) and Tic (47.05%) fractions were obtained in E-PTC after 8 h of ED period. The resulting E-PTC had stronger coagulation capability for both surface water and municipal wastewater treatment than the conventional ones. Compared with the conventional Al-based and Fe-based coagulants, E-PTC achieved 15% to 30% higher removal of organic matter, and produced the flocs with larger size, faster growth rate, better dewaterability, stronger strength and recoverability. This study provided the efficient ED method for the preparation of Ti-based coagulants with superior flocculation performance.

Transcriptome and Coexpression Network Analyses Provide In-Sights into the Molecular Mechanisms of Hydrogen Cyanide Synthesis during Seed Development in Common Vetch (Vicia sativa L.).

The common vetch (Vicia sativa L.) seed is an ideal plant-based protein food for humans, but its edible value is mainly limited by the presence of cyanogenic glycosides that hydrolyze to produce toxic hydrogen cyanide (HCN), and the genes that regulate HCN synthesis in common vetch are unknown. In this study, seeds from common vetch at 5, 10, 15, 20, 25, 30, and 35 days after anthesis were sampled, and the seven stages were further divided into five developmental stages, S1, S2, S3, S4, and S5, based on morphological and transcriptome analyses. A total of 16,403 differentially expressed genes were identified in the five developmental stages. The HCN contents of seeds in these five stages were determined by alkaline titration, and weighted gene coexpression network analysis was used to explain the molecular regulatory mechanism of HCN synthesis in common vetch seeds. Eighteen key regulatory genes for HCN synthesis were identified, including the VsGT2, VsGT17 and CYP71A genes, as well as the VsGT1 gene family. VsGT1, VsGT2, VsGT17 and CYP71A jointly promoted HCN synthesis, from 5 to 25 days after anthesis, with VsGT1-1, VsGT1-4, VsGT1-11 and VsGT1-14 playing major roles. The HCN synthesis was mainly regulated by VsGT1, from 25 to 35 days after anthesis. As the expression level of VsGT1 decreased, the HCN content no longer increased. In-depth elucidation of seed HCN synthesis lays the foundations for breeding common vetch with low HCN content.

Influential mechanism of water occurrence states of waste-activated sludge: Potential linkage between water-holding capacity and molecular compositions of EPS

The water occurrence states in waste-activated sludge (WAS) are crucial to its dewaterability and significantly influenced by the water-retaining capacity of extracellular polymeric substances (EPS) matrix. Accordingly, the non-selective •OH-oxidation processes were widely reported for the sludge dewaterability improvement, just because it can non-selectively destruct complex structure units of EPS, no matter these structure units are crucial to EPS water-holding capacity or not. But these non-selective processes may also require the large consumption of oxidant chemicals, which limits their wide application. This study specifically focused on the •OH-induced variation in molecular compositions of EPS and the corresponding effects on water occurrence states of WAS, which is expected to lay a foundation for optimizing the efficiency of oxidation-based sludge conditioning. Especially, through a novel method based on the equilibrium dialysis with alkaline titration, the typical hydrophilic functional groups of EPS were quantitatively analyzed. The results indicated that the free amino group (-NH2) had the greater impact on the water-holding capacity of EPS than the acidic hydroxyl groups (-OH). Nevertheless, by Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS), the hydrophilic heteroatom classes (e.g. N:Cw) were found to be less sensitive to the varying oxidant dosage than the molecular saturation degree (e.g. weighted averages of double bond equivalents (DBEw) and aromatic index (AImod,w)). •OH modified the nitrogen-containing or oxygen-containing functional groups, but could not completely remove these hydrophilic functional groups from EPS macromolecules. Therefore, the potential competition for •OH between the hydrophilic functional groups and the unsaturated structure units of EPS was clarified, which guides directions that developing highly-efficient sludge conditioning approaches should be based on the selective removal of hydrophilic functional groups instead of improving •OH production efficiency.

Effect of Different Thermal Techniques on Anti-Nutritional Compunds With Special Refefence to Hydrogen Cyanide in Linum usitatissimum

Flax is one of the world’s primordial crops with proceedings of human cultivation extending back to thousands of years. Objective: To observe the comparative effectiveness of different thermal treatments on hydrogen cyanide (HCN) contents in flaxseed (Linum usitatissimum L.). Methods: For the purpose, flaxseed was procured from local market, Faisalabad-Pakistan. Then, it was characterized for nutritional composition and mineral profiling through respective methods. In addition, dietary fiber, fatty acids, lignans and hydrogen cyanide (HCN) content were assessed through Enzymatic-gravimetric methods, gas chromatography-mass spectrometry (GCMS), high performance liquid chromatography (HPLC) and alkaline titration, respectively. Moreover, different heat treatments i.e. autoclaving, microwave roasting, oven heating and water boiling were applied to mitigate the hydrogen cyanide contents. Results: Results of alkaline titration before heat treatment showed that hydrogen cyanide content was 376.0 mg/kg in flaxseed. The effect of heat treatments on hydrogen cyanide content of flaxseed was found to be highly significant. Hydrogen cyanide content was reduced to 22.33 mg/kg, 62.792 mg/kg, 204.33 mg/kg and 300.048 mg/kg by water boiling, microwave roasting, autoclaving and oven heating, respectively. Conclusion: Water boiling is most effectual technique (98% reduction) while oven heating is the slightest one (20.2% reduction).

Integration of complete elemental mass-balanced stoichiometry and aqueous phase chemistry for bioprocess modelling of liquid and solid waste treatment systems – Part 4: Aligning the modelled and measured aqueous phases

Completely mass-balanced biological, physical and chemical process stoichiometry ensures that the CHONPS material and charge content entering and exiting bioprocess system models is conserved, which is a requirement for pH prediction in integrated physical, chemical and biological process models. Bioprocesses transform the material content from reactants to products, exchanging material between the aqueous, gaseous and solid phases, which cause pH changes in the aqueous phase. By measuring the material content of the aqueous phase, the progress of bioprocesses can be monitored. Alkalinity is an important aqueous-phase property that can be used to track aqueous-phase changes caused by physical, chemical and biological processes. Alkalinity is a stoichiometry property of the components in solution (i.e., a linear function of the amounts present). Its uptake from, and release to, the aqueous phase can both be modelled with bioprocess stoichiometry, and measured in physical bioprocess systems, and so aid in linking the modelled and measured aqueous-phase compositions. Changes in the concentrations of components containing the elements C, H, O, N, P and S result in changes in six weak acid/bases systems in the aqueous phase, all of which affect the total alkalinity. These are: inorganic carbon (IC), ortho-phosphate (OP), free and saline ammonia (FSA), volatile fatty acids (VFA), free and saline sulphide (FSS) and the water itself. Characterization of the aqueous phase to quantify the material content of the aqueous phase containing these six weak acid/base systems using the 5-point titration method is described. While several alkalinity titration based methods are available for anaerobic digestion bioprocess monitoring, only the 5-point titration is sufficiently accurate for aqueous-phase characterization to quantify the aqueous-material content for pH prediction in bioprocess models.

Deprotonation and aggregation of Al13 under alkaline titration: A simulating study related to coagulation process

Unraveling the transformation of coagulants and their interaction with contaminants at the micro-level is vital to advancing our understanding of the coagulation mechanism. To the best of our knowledge, the coagulation effectiveness of [AlO4Al12(OH)24(H2O)12]7+ (Al13), regarded as the dominant species in polyaluminum chloride (PACl), is highly related to its aggregation characteristic, but the detailed process of Al13 aggregation in coagulation time scale was not well studies. Here we systematically studied the deprotonation and aggregation processes of Al13 by alkaline titration to simulate the reaction in coagulation case. By reacting with OH−, Al13 can continuously lose protons regardless of pH until its positive charge was well neutralized. The initial Al13 aggregates (Al13agg) appeared at B of 2.70 and large Al13agg was generated by coalescence of small initial Al13agg. Most Al13 polycations kept their main structure unchanged during aggregation and part was decomposed into monomers or oligomers. Density functional theory (DFT) results reveal that Al13 becomes unstable after deprotonation, but the aggregation of Al13 bridged by Al monomers can stabilize the polycations. Al13 needs to be hydrolyzed before interacting with colloidal particles, but particles can promote the aggregation of Al13 by weakening the repulsion force between the polymers. Strong and compact flocs can be generated induced by in-situ aggregation of Al13 in neutral and alkaline conditions. This study can provide a deep understanding about the role of Al13agg in removing particles and instruct the development of new efficient coagulants against the various water qualities.

Analysis of the Physicochemical Parameters and Microbiological Quality of Water Samples Obtained from Mbiaso River and Enang Stream in Ikot Ekpene Metropolis

The physicochemical, microbiological and heavy metal studies of water samples obtained from Mbiaso River and Enang Stream were investigated. Water samples were collected from two locations with two sampling points from each location along the course of the water body based on their use by the community and analysed using standard procedures. The results obtained were compared with WHO standards for drinking and recreational water. Aside titratable acidity, titratable alkalinity and BOD, all other physicochemical parameters were within the permissible standards. All the heavy metals concentrations were above the permissible limits except for Lead (Pb) that ranged between 0.01mg/l to 0.05 mg/l for all the sampling points. All the water samples were found to harbor coliforms organisms in numbers greater than the required WHO standards for water except for Enang river that lacked the presence of Vibrio spp. The total viable counts for all the water samples were generally high exceeding the standard limit of 1.0 x 102 cfu/ml for water. The total heterotrophic bacteria count, total coliform count, faecal coliform count and total fungal count ranged between 1.9x104 - 52x104 cfu/ml, 2.3x104 -38 x104 cfu/ml, 1.7x104 - 30x104 cfu/ml and 2.5x104 - 5.3x104 cfu/ml respectively. The total salmonella-shigella counts and total staphylococcus counts were in the range of 0.2 x102-0.4 x102 cfu/ml and 0.3 x102 -0.6 x104 cfu/ml respectively. From the study, it is suggested that some regulations measures be put in place to control pollution of the water while the water be properly treated before use for domestic, potable or recreational purposes.

Anti- nutrient contents of herbs used in the treatment of “ailments of ‘‘utmost native importance” in Cross River State, Nigeria

The use of herbs as medications are enthusiastically recognized and extensively utilized in rural regions and in most developing countries. The lack of knowledge of the anti-nutrient contents of herbs reduces their use by the educated ones. To unveil these in the treatment of “ailments of utmost native importance” in Cross River State, this research carried out anti-nutrient analysis of the species used. Identified plants were separated from weeds and washed with water. The plant parts were processed and their extracts prepared according to the method described by Kumar et al., (2007). Hydrocyanic acid was estimated by the alkaline titration method, oxalate was determined according to procedures stipulated by Day and Underwood (1986) while phytic acid was determined using methods stipulated by Reddy and Love (1999). Results revealed that Phytic acid, oxalate and hydrocyanide all had low levels ranges of 2.47mg/100gDM to 6.17mg/100g DM, 12.82mg/100g DM to 30.41mg/100g DM and 1.62mg/100g to 6.23mg/100g DM respectively. Findings shows that these anti-nutrients are not within harmful ranges, and as such cannot interfere with the availability of potentially useful nutrients embedded in the species. These are below lethal doses to inflict any injury on humans.&#x0D; Keywords: Herbs, Anti-nutrients, Ailments, Lethal dose, Efficacy.