Optimum Acid Concentration Research Articles

Sulfuric acid solvolysis of cellulose in a butanol-1/benzene mixture for isolating cellulose nanocrystals

The absence of a universal method for isolating cellulose nanocrystals (CNCs) has prompted researchers to explore alternative approaches to traditional sulfuric acid hydrolysis. In this study, the authors continue their previous research by investigating CNC synthesis through cellulose solvolysis in an alcoholic environment. The CNCs were successfully obtained utilizing controlled sulfuric acid solvolysis of sulfate cellulose in a butanol-1/benzene mixture. The highest CNC yield (over 60 %) was achieved at strictly controlled acid-to-benzene ratios in a butanol-1/benzene/sulfuric acid reaction mixture, with a significant reduction in the optimal acid concentration. The study also analyzes the physicochemical properties of the isolated CNCs. No surface alkylation of the synthesized CNCs was observed during the cellulose solvolysis in the butanol-1/benzene mixture. Besides, the properties of these CNCs closely resembled those obtained through traditional sulfuric acid hydrolysis. The paper also discusses the potential mechanism of cellulose solvolysis in the process of CNC production.

A Two-Step Leaching Process Using Thiourea for the Recovery of Precious Metals from Waste Printed Circuit Boards

The development of efficient recovery methods for waste printed circuit boards (WPCBs) not only tackles the environmental risks of disposal but also promotes the conservation of resources within the electronics industry. This study proposes a two-step leaching approach for recovering metals from WPCBs. Initially, transition metals are leached using nitric acid, followed by the recovery of precious metals with thiourea in the second stage. In the first stage, dissolution rates exceeding 90 wt% were achieved for transition metals, including Cu, Fe, Ni, Pb, and Sn. In this stage, the dissolution of precious metals (i.e., Au and Pd) was insignificant. In the second stage, the effect of four parameters was investigated, including the impact of temperature, concentrations of ferric ions, sulfuric media, and thiourea on the recovery of Au and Pd. Precise control over sulfate concentration played a vital role in achieving maximum Au recovery. The optimal acid concentration was 0.2 M, resulting in a recovery rate of ~50 wt%. Ferric ion concentration positively affects Au recovery, whereas, in extracting Pd, optimal conditions imposed the absence of ferric ions. Thiourea concentration positively impacted Au and Pd recovery rates, peaking at 49 wt% for Au at 1 M and 44 wt% for Pd at 1.5 M. Prolonged leaching resulted in declining Au recovery rates, indicating a decrease in reagent concentration. Temperature variation yielded similar outcomes, with 50 °C resulting in peak recovery rates of 53 wt% for Au and 54 wt% for Pd. Metal dissolution kinetics during leaching were analyzed using pseudo-first-order and pseudo-second-order models. The second-order model proved suitable for transition metals in the first stage, while only for Au and Pd in the second stage (with R2 = 0.99).

Enhancing the photostability and mechanical properties of poly‐lactic acid (PLA) composites with glutaric acid functionalized titanium dioxide (TiO2)

AbstractThe performance of Poly(lactic acid) (PLA) composites reinforced with functionalized titanium dioxide (TiO2) nanoparticles in rutile and anatase crystalline phases were systematically investigated. The results underline that the incorporation of TiO2, regardless of its crystalline structure, significantly enhances PLA's crystallinity by 85%. Notably, rutile TiO2, when functionalized with higher glutaric acid concentrations, was an effective crystallinity booster by 95%, passing from 20.39% to 39.58% crystallinity for the PLA/TiO2 R20 + 10% system. Furthermore, this research elucidates that the selection between anatase and rutile phases plays a vital role in the photostabilization. Functionalized Rutile TiO2 exhibited exceptional UV resistance, effectively inhibiting photodegradation; for example, after 15 days of exposure, the functionalized systems exhibited a 497.6% improvement for PLA/TiO2 R10 + 5% (22.1 ± 2.5 MPa), while the PLA/TiO2 R10 + 5% showed an 85.1% increase in composite stiffness (35.5 ± 3.5 MPa) after 7 days of degradation, in comparison with pristine PLA (19.2 ± 2.9 MPa). Anatase, conversely, displayed varying effects depending on concentration, acting as a stabilizer at lower levels and a promoter of degradation at higher concentrations. This knowledge enables the precise modifying of PLA composites for specific applications, balancing crystallinity, mechanical properties, and UV resistance for a diverse array of applications.Highlights TiO2 enhances photostability in PLA confirming its potential as a UV stabilizer. Comparing anatase and rutile phase: Unveiling PLA composite dynamics. Glutaric acid on TiO2 enhances PLA composite strength significantly. Optimal acid concentration key to composite performance. Tailored PLA composites balance crystallinity, mechanics, and UV resistance.

Utilization of Palm Oil Waste into Liquid Smoke in Cellulose Commercial Starch Nano Fiber Composite as Antimicrobial Substances in the Manufacturing of Food Packaging

The high demand for plastic use today will result in environmental damage because the plastic that is widely used cannot be broken down. This plastic waste is dangerous for the sustainability of the food chain, pollutes water and soil, causes global warming, and causes air pollution. This research synthesizes a cellulose nanofiber composite with commercial starch in a 1:1 ratio with the influence of the addition of smoke liquid from palm oil waste. This research aims to process cellulose nanocomposite fibers combined with commercial starch and use them in biodegradable plastic by testing the effect of giving smoke liquid on the development of microbial substances in environmentally friendly biodegradable plastic food packaging. So the resulting product is expected to have the potential to reduce dependence on the use of synthetic plastic. This research aims to determine the optimum concentration of liquid acid from empty oil palm fruit bunches as an antimicrobial agent in the resulting bioplastic. The addition of liquid smoke changes the bioplastic properties of FTIR and XRD the attractive strength of bioplastic. The sample with the highest concentration of liquid smoke had the greatest tensile strength (2.34 MPa). The addition of liquid smoke concentration from empty oil palm shells showed a good inhibitory area for the development of bacillus cereus (10.8 mm).
 Keywords: liquid smoke, plastic biodegradable, food packaging, antimicrobial

Optimization of a pre-concentration method for the analysis of mercury isotopes in low-concentration foliar samples.

Hg isotope analysis in samples from background regions is constrained by the presence of low Hg concentration and therefore requires a pre-concentration method. Existing Hg pre-concentration methods are constrained by long sample processing time and limited sample loading capacity. Using foliar samples as a test case, an optimized Hg pre-concentration method is presented that involves the microwave-assisted digestion of samples for Hg isotope analysis with the addition of a pre-digestion step. Microwave-digested foliar samples and CRMs were transferred to an impinger, reduced with SnCl2, and collected in a 2.25 mL concentrated inverse aqua regia (3:1 HNO3:HCl, v/v). This resulted in an optimal acid concentration in the solution ideal for analysis on MC-ICP-MS. The time for purging with Hg-free N2 was optimized to 30 min and the efficiency of the pre-concentration method was tested using a combination of approaches. Tests performed on pure reagents and matrix of foliar samples spiked with 197Hg radiotracer showed recoveries averaging 99 ± 1.7% and 100 ± 3.0%, respectively. Mercury at concentrations as low as 1.83 ng g-1 was pre-concentrated by digesting aliquots of foliage samples in individual digestion vessels. Recoveries following their pre-concentration averaged 99 ± 6.0%, whereas recoveries of 95 ± 4.7% and 95 ± 2.5% were achieved for NIST SRM 1575a (pine needle) and reagents spiked with NIST SRM 3133, respectively. Analysis using multicollector-ICP-MS showed low fractionation of δ202Hg during sample pre-concentration with no significant mass-independent fractionation. The proposed method is a relatively simple and robust way to prepare Hg samples for Hg isotopic analysis and is suitable even for complex biological matrices.

Interaction of alkaline and acid treatment on the removal of proteinaceous mineral-enriched dairy fouling from UHT treatment

CIP processes in milk processing plants are frequently oversized to reliably meet hygienic and safety requirements. Cleaning follows a fixed protocol, but the exact mechanisms and intermediate products are often unknown. This study presents an experimental approach to elucidate the interaction between alkaline and acidic treatment with special regard to the impact of acid on proteinaceous deposits. The protein containing fouling layers become yellowish in colour by acidic treatment; this is attributed to the xantho-proteic reaction and no efficient removal is thereby achieved. In contrast, the removal is efficient if an efficient initial alkaline treatment step is performed. An efficient initial alkaline treatment step was identified as crucial for the further course of cleaning and a short alkaline treatment soaked the entire soil, which enabled an efficient subsequent acidic removal. Lower concentrations of HNO3 demonstrate more efficient cleaning than higher ones, suggesting an optimum acid concentration during CIP.

Characterization of Nanocellulose from Orange Peel Waste

Orange peel is a commercially available natural fiber with an increasing interest in using it as a raw material in a variety of applications due to its high cellulose concentration in the plant. This research aims to determine the preparation of nanocellulose from orange peel waste (OPW) by using chemical treatment of acid hydrolysis method. In order to provide the optimum conditions of nanocellulose of OPW which are possessed high crystallinity in their crystal structure by using acid hydrolysis method and the effects of various acid concentrations on the crystallinity index, crystallite size and morphology of cellulose nanocrystals were studied. However, based on the previous study, using OPW there is limited study has been reported on type of acid and optimum acid concentration as a parameter of using hydrolysis method. Therefore, in this study, the process of preparation OPW nanocellulose by using acid hydrolysis method with the best type of acid used of sulphuric acid (H2SO4) and hydrochloric acid (HCl), optimum acid concentration (30-40 wt%), constant hydrolysis time (120 min) and constant temperature (45 °C) is comprehensively studied. Based on the achieved outcomes, the H2SO4 emerges as the most favorable approach for acid hydrolysis technique, effectively yielding finely dispersed crystalline cellulose while mitigating undesirable aggregation effects. The optimal acid concentration of 30 wt%, coupled with a 120 minute hydrolysis duration and a temperature of 45 °C, yields the most favorable results in terms of both crystallinity index and crystallite size, reaching remarkable values of 87.69 % and 3.19 nm, respectively. The nanocellulose derived from OPW holds significant potential as an environmentally sustainable material, aligning harmoniously with prevailing global trends in design and development for enhanced sustainability.

Research on high efficiency and retarded autogenous mud acid for plugging removal in a sandstone reservoir—Example of Bai 823 well area

AbstractAcidification, as an effective measure to remove blockages and restore oil well productivity, has received widespread concern. However, conventional acid systems can only be used to unblock near‐wellbore zones and are difficult to act on far‐wellbore reservoirs. In this article, scanning electron microscope, energy‐dispersive X‐ray spectroscope, and X‐ray diffractometer were used to analyze the blockages in the Bai 823 well area, and it was determined that their main components were CaCO3 and FeCO3, which provided the basis for the construction of the unblocking formula. Then, the acid dissolution experiments on the plugging materials showed that the dissolution rate of 10% HCl can reach more than 85% for the scale sample; the acid dissolution experiments on the rock sample showed that the autogenous mud acid has better dissolution performance and better retardation performance for the rock sample, and the effective action time is longer, so it can be used for deeper unplugging of the reservoir. Finally, the process parameters such as the optimal acid concentration, acid dosage, and discharge volume were optimized by establishing the fracture‐matrix acid flow reaction model. Research results indicate that the autogenous mud acid can act on the blockage in the far‐wellbore area to improve the acidification effect.

Effect of protonic acid concentration on electrical properties of fly ash magnetic beads/polyaniline composites

AbstractMagnetic polyaniline nanofibers were synthesized by oxidative polymerization using protonic acid and fly ash magnetic beads as dopants and ammonium persulfate as oxidant. The synthesized magnetic polyaniline was characterized by FT‐IR, UV, XRD and SEM, and its morphology and structure were revealed. Polyaniline magnetic electrodes were prepared by pressing method, and their electrochemical properties were analyzed by cyclic voltammetry and constant current charge–discharge methods. The capacities of polyaniline powders doped with optimal concentration of hydrochloric acid and p‐toluene sulfonic acid at current density of 1 A/g were 250.75 and 410.5 F/g, respectively. The magnetic polyaniline doped with optimal acid concentration has good conductivity through impedance measurement analysis. A smooth and uniform film was prepared by pressing magnetic polyaniline powder and its photosensitivity was observed under different monochromatic illumination. The results show that the current and voltage have a linear relationship and that different monochromatic light energies can be distinguished significantly with the increase of voltage.

PROTON EXCHANGE MEMBRANE FUEL CELL; EMPIRICAL REVIEW ON THE DEGREE OF SULPHONATION

Empirical review on the degree of sulphonation of polymeric materials for proton exchange membrane fuel cell (PEMFC) was carried out. Fuel cell generally applies the principle of electrochemistry in which chemical energy is converted directly into electrical energy. Amongst the league of fuel cells, the proton exchange membrane fuel cell is the most promising. However, the central component of PEMFC is the ionic polymer membrane that must be rendered conductive. This study showed that the measure of sulphonation is pivotal in achieving conductivity of the polymer for fuel cell application. The study revealed that for an optimum conductivity to be achieved, optimum degree of sulphonation (DS) is needed. The recognized factors that affect the optimum degree of sulphonation were the type of sulphonating agent (as chlorosulponic acid achieved 39.04% and 50.21% differential increment over both sulphuric acid and fuming sulphuric acid, respectively), sulphur content (while the lowest Sc of 1.76% achieved 9.13% DS, the highest Sc achieved 20.04% DS), optimum acid concentration (as DS of 20.04 % was achieved with 1.6 mmol/g as against 2.0 mmol/g of 16.76 %), nature of the polymer base material (as more –SO3H groups attached to aliphatic polymers than aromatic), optimum time and stirring speed, optimum temperature, and optimum weight of the base polymer. The study was able to unravel that the degree of sulphonation can be determined via elemental sulphur analysis either by analytical or titrimetric method. The study also showed that the degree of sulphonation can be predicted correctly using a predictive model.

Humic Acid-Amended Formulation Improves Shelf-Life of Plant Growth-Promoting Rhizobacteria (PGPR) Under Laboratory Conditions

Plant growth-promoting rhizobacteria (PGPR) is a soil bacterium that positively impacts soil and crops. These microbes invade plant roots, promote plant growth, and improve crop yield production. Bacillus subtilis is a type of PGPR with a short shelf-life due to its structural and cellular components, with a non-producing resistance structure (spores). Therefore, optimum formulations must be developed to prolong the bacterial shelf-life by adding humic acid (HA) as an amendment that could benefit the microbes by providing shelter and carbon sources for bacteria. Thus, a study was undertaken to develop a biofertilizer formulation from locally isolated PGPR, using HA as an amendment. Four doses of HA (0, 0.01, 0.05, and 0.1%) were added to tryptic soy broth (TSB) media and inoculated with B. subtilis (UPMB10), Bacillus tequilensis (UPMRB9) and the combination of both strains. The shelf-life was recorded, and viable cells count and optical density were used to determine the bacterial population and growth trend at monthly intervals and endospores detection using the malachite green staining method. After 12 months of incubation, TSB amended with 0.1% HA recorded the highest bacterial population significantly with inoculation of UPMRB9, followed by mixed strains and UPMB10 at 1.8x107 CFUmL-1, 2.8x107 CFUmL-1and 8.9x106 CFUmL-1, respectively. Results showed that a higher concentration of HA has successfully prolonged the bacterial shelf-life with minimal cell loss. Thus, this study has shown that the optimum concentration of humic acid can extend the bacterial shelf-life and improve the quality of a biofertilizer.

Production of fine-dispersed tungstic acid

The paper presents the results of studies of fine-grained tungstic acid synthesis and research of tungsten trioxide obtained from it. A literature analysis was performed and the direction of the study was formulated. A method of precipitation of tungstic acid from sodium tungstate solutions by hydrochloric acid solution has been proposed. To produce tungstic acid, a continuous operation unit that provided the required draining rates of sodium tungstate and hydrochloric acid solutions, the temperature of draining solutions and their concentrations, was created. The dependence of the specific surface of the obtained tungstic acid on the concentration of the used hydrochloric acid was investigated, and the optimum concentration of hydrochloric acid at 430 grams per liter was determined. Using the mathematical method of simplex-planning experiments, the effect of three parameters on the specific surface area of tungstic acid — the concentration of sodium tungstate solution, the ratio of volume rates of drained solutions, and the temperature of drained solutions, was investigated. The following, close to optimum parameters have been received: concentration of sodium tungstate solution of 35–40 grams per liter, ratio of concentrated (430 g/l) hydrochloric acid to the volume of sodium tungstate solution is (1.9–2.0):1, temperature of solutions is 15–20 °С. Tungstic acid with a specific surface area of 60 m2/gram was obtained. It is determined that for the preparation of tungsten trioxide with a high specific surface area, the heating rate of tungsten acid in its drying must be 40–50 degrees per hour and the final drying temperature must be equal to 400 °C. Figures illustrating the dependence of the specific surface of the obtained tungstic acid on the concentration of sodium tungstate solution, the ratio of the volume velocities of the drained solutions and the temperature of the drained solutions are presented.

The Application of the Activated Carbon from Cordia africana Leaves for Adsorption of Chromium (III) from an Aqueous Solution

The objective of this study is to investigate the adsorption performance of activated carbon derived from the leaves of Cordia africana for the removal of Cr (III) from an aqueous solution. The plant sample was collected, washed, dried, grounded, and sieved at 125 μm mesh size. Adsorbent activation was done using H3PO4 at concentrations of 25–85% and pyrolysis temperature of 400–500°C. The activated carbon was characterized by proximate, SEM, BET, and FTIR analyses. A batch adsorption study was conducted to determine the effect of contact time, adsorbent dose, initial chromium concentration, and mixing speed on Cr (III) removal. The regeneration of the activated carbon was investigated by using 1 M of HNO3 as a desorbing solution for seven cycles. At optimum acid concentration and pyrolysis temperature, a surface area of 700 m2/g was recorded. The moisture content, volatile matter, ash composition, fixed carbon, and bulk density of the activated carbon were found to be 5.3%, 24.2%, 6.2%, 64.3%, and 0.75 g/mL, respectively. The SEM and FTIR analyses indicated that the surface morphology was full of cracks and different peaks were associated with plenty of functional groups, respectively. The maximum Cr (III) removal was attained at a contact time of 180 min (89%), adsorbent dose of 1.5 g (54%), initial concentration of 0.6 g/L (47%), and mixing speed of 300 rpm (64%). The equilibrium data were better described by Freundlich isotherm at R2 value of 0.88, which implies that the adsorption process is conducted on a heterogeneous surface. The pseudo-first-order kinetics model with R2 value of 0.99 best fits with the equilibrium data, which implies that physisorption controls the adsorption kinetics. Generally, it can be concluded that this locally prepared adsorbent is promising for the removal of chromium from industrial wastewater, but further factorial approach assessment has to be checked.

Development of effective expanded vermiculite flocculant for enhanced primary treatment of swine wastewater: Lab-scale investigations

Flocculation is an essential process to purify the swine wastewater which generally contains high concentration of suspended colloids and phosphorus. In this study, a novel acidified expanded vermiculite flocculant (A-EV) was developed to efficiently remove phosphorus and suspended solids (SS) from the swine wastewater. EV and A-EV were fully characterized to understand their properties. The optimum acid concentration was determined to be 20%. It was demonstrated that A-EV exhibited better performance than the widely used polyferric sulfate (PFS), giving rise to more compact and faster settled flocs. The volume of the supernatant accounted for PFS was only 34% of the total volume, while for A-EV, the volume of the supernatant accounted was 66%. When the dosage of A-EV was 1500 mg/L, the removal efficiency of SS, turbidity, COD and TN in the swine wastewater were 95.7%, 70.0%, 38.8% and 21.9%, respectively. The toxicity of A-EV was also evaluated to ensure its biosecurity. Zeta potential analysis revealed that adsorption - charge neutralization was the dominant mechanism. The excellent flocculating performance of A-EV is attributed to the synergistic effect of acid-soluble salts and non-soluble silicon frame. Our study indicated that A-EV could be regarded as a green and effective flocculant for effective enhanced primary treatment of the swine wastewater.

Biocatalytic intensified process for the synthesis of neopentyl glycol dicaprylate/dicaprate

Emollient esters are widely used ingredients in the cosmetics industry. Their chemical synthesis requires the use of high temperatures and polluting acid catalysts, resulting in environmentally unfriendly processes.This paper describes, for the first time, the biocatalytic synthesis process of the cosmetic ingredient neopentyl glycol dicaprylate/dicaprate (INCI name), a mixture of branched diesters with excellent emollient properties. The co-esterification of the acids with the alcohol is carried out in a solvent-free system, using the biocatalyst Lipozyme®435, a commercial immobilized derivative of Candida antarctica lipase B marketed by Novozymes.Process intensification has been approached by acting on three different aspects. Firstly, the use of solvent-free systems provides higher yields by operating with smaller reactor volumes. Secondly, the inhibition of the enzymatic activity caused by caprylic and capric acids has determined the need to implement a new reaction strategy consisting in the use of a fed-batch reactor, in which the acid is added to the reactor using a peristaltic pump in order to maintain an optimal acid concentration that minimizes the inhibition effects. Finally, the reusability of the biocatalyst used has been verified, allowing it to be used in at least five consecutive reaction cycles without noticeable loss of activity.All this results in an efficient synthesis process with a process productivity of 0.15 kg product/L reactor·h and a biocatalyst productivity of 167.09 kg product/kg biocatalyst. Only 6 h are needed, operating in a fed-batch reactor at 80 °C, to obtain a product with 92.5% purity. In addition, the most commonly used sustainability indicators have been calculated, reflecting that the biocatalytic process developed for the synthesis of neopentyl glycol dicaprylate/dicaprate complies with many of the principles of "green chemistry" and is suitable for future implementation on an industrial scale.

Halogen–Hydrogen Bonding for the Synthesis of Efficient Polymeric Carbon‐Nitride Photocatalysts

Carbon nitride (CN) materials demonstrate great promise as photocatalysts for various reactions. However, synthesizing a CN with high dispersibility in water, large specific surface area, ordered morphology, and high catalytic activity remains a challenge. Melem (2,5,8‐triamino‐tri‐s‐triazine) has emerged as a monomer for the synthesis of CN materials owing to its high thermal stability, which favors controlled condensation over sublimation and decomposition at high temperatures. Herein, the synthesis of porous CN materials is shown with high dispersibility in water and excellent photocatalytic activity for the hydrogen evolution reaction (HER). To this end, various supramolecular assemblies are designed which are composed of melem combined with different hydrohalogenic acids as precursors of CNs. The results show that the HX (HX (aq), where X = Cl, Br, I) type directs the morphology, optical, and electronic properties of the resulting CN materials, particularly their surface area and photophysical properties. Moreover, the presence of HX results in a CN with a larger amount of free NH2 groups, which allow good dispersibility in water and act as linking groups to a photodeposited Pt cocatalyst. The elucidation of the optimum acid concentration and type leads to the synthesis of a CN with high and stable photocatalytic HER activity.

Durability of Recycled Concrete Aggregates Prepared with Mechanochemical and Thermal Treatment.

Recycled concrete aggregates (RCAs) have low quality when compared with natural or conventional aggregates as the paste adhering to it is the key aspect that affects its functionality. Since the adhering cementitious paste weakens the adhesion between the aggregate and the binder, it becomes a decisive factor in the mechanical behavior of the asphalt mixture. It turns out that enhancing the surface of the aggregate or eliminating the paste attached to the NA (natural aggregate) is crucial for improving interfacial bonding. Therefore, the treatment and evaluation of the RCAs by laboratory testing method were studied in this research to assess their reuse in the asphalt pavement surface coarse layer. With the various techniques for removing paste from the RCA, a combination of three enhancement processes were developed for the effective removal of the cement paste, which are mechanical, chemical, and 400 °C conditioning thermal treatment. The RCAs were first charged in a Los Angeles machine for the mechanical treatment to remove parts of the attached cement. Then they were soaked in two types of acids, namely hydrochloric and sulfuric, with different concentrations to determine the most effective or optimum molarity for about a 48 h soaking duration. Then a 2 h thermal treatment was conducted on the RCA samples. After all the treatments were done, the RCA aggregates were subjected to different types of tests to examine their properties in order to ensure their full potential in terms of their physical, chemical, mineralogical, and surface microstructure characteristics. Based on the experiment design, the study intends to examine the quality of the treated recycled aggregates generated by the combination approach as well as to investigate the optimal acid concentration and type. The results show that the proposed mechanochemical and thermal treatment reinforced the quality of the RCAs when compared to the non-treated samples. Meanwhile, HCl proved to be the optimum compared to H2SO4 in most examinations of the properties. In the end, better chemical qualities were validated, and the RCA qualities were improved.

Effects of Sucrose and Gibberellic Acid on Growth and Survival of Local Potato (Solanum tuberosum L.) Varieties in vitro in Kenya

Tissue culture techniques’ have become useful technologies for producing disease & pest free seed potato (Solanum tuberosum L.) in the developed world. However, these techniques have yet to be standardized for locally produced potato varieties in Kenya. Developing countries can also use these innovations for rapid multiplication of popular local seed material through rooted apical cuttings generated from either plantlets or micro tubers. In vitro experiments were therefore conducted to determine the optimum concentration of sucrose and gibberellic acid for growth and survival of local potato varieties, namely, Shangi, Unica and Wanjiku. The explants were cultured in Murashige and Skoog (MS) media supplemented with sucrose at a concentration of 20, 30 and 40 gL-1, while gibberellic acid was applied at a concentration of 0.2, 0.5 and 1.0 mgL-1. The study was laid out in a completely randomized design (CRD). MS Medium with sucrose 40 gL-1and gibberellic acid 0.5 mgL-1 significantly enhanced shoot length, with the longest shoot (10.3cm) being recorded for Wanjiku. The same treatment also gave the highest plant survival of 90%. Murashige and Skoog media, added with 0.5 mgL-1 gibberellic acid along with 40 gL-1 sucrose is recommended for generating wanjiku, unica and shangi apical rooted cuttings because it gave the best improvement of in-vitro clonal growth.

Comparison of Saccharification And Lactic Acid Production Efficiencies From Chemically and Biologically Pretreated Wheat Straw

Background In recent times, agricultural waste has been utilized in many industries as an energy source in several processes. Wheat straw, one of the most cost-effective raw material, has a great potential to be utilized as a substrate in fermentation to produce lactic acid. Utilization of agro waste material as the carbon source provides a cheap and environment friendly production of lactic acid. Methods A comparison of chemical and biological pretreatment of wheat straw and the use of pretreated wheat straw hydrolysate in fermentation of Lactobacillus was carried out using optimized process parameters of temperature and ph. Pretreatment methods using dilute acid and white rot fungus Coriolis versicolor were performed on wheat straw as well as the effect of copretreatment with calcium hydroxide on differentially pretreated wheat straw was studied by analyzing sugar and lactic acid concentrations during fermentation. The effect of different pH (7, 8, and 9) on fermentation using dilute acid pretreated wheat straw was observed to lower the lactic production with the increase in ph. Dilute acid pretreatment of wheat straw provided the highest concentration of glucose at 57.2mg/L and subsequently enhanced yield of lactic acid during fermentation while the biologically pretreated wheat straw hydrolysate provided comparatively lower concentration of glucose at 49.2mg/L and thus decreased lactic acid production. Result The final lactic acid concentration of 48.14 mg/L was obtained in dilute acid pretreated wheat straw with Yp/s of 0.915 mg/mg, while the use of biologically pretreated wheat straw hydrolysate provided 39.56 mg/L concentration of lactic acid and an Yp/s of 0.908 mg/mg. However, a reduced lactic acid concentration of 27.03 mg/L and 20.62 mg/L was seen after the co-pretreatment of both dilute acid and fungal pretreated wheat straw with calcium hydroxide respectively, indicating its adverse effects on fermentation process. Conclusion Pretreatment of wheat straw with dilute acid can be considered a good saccharification method to obtain the optimum concentration of lactic acid in microbial fermentation carried out at optimum temperature and pH conditions.

Copper, chromium and nickel recovery from electroplating sludge using acid digestion method

ABSTRACT Industrial production operations generate huge amounts of heavy metals enriched sludge. Due to inadequate management and illegal disposal practices, this waste sludge can deteriorate human and environmental health. For sustainable environmental development and conserving human health, sludge should be recycled to recover the heavy metals and the treated sludge (with permissible or safe limits of heavy metals) should be used to improve the soil fertility and physical properties. Herein, a study is carried out to identify the optimum concentration of sulphuric acid (H2SO4) to remove copper (Cu), nickel (Ni) and chromium (Cr) from the waste sludge and the number of organic matter residues that remained after the acid digestion. Besides, the optimum pH to precipitate Cu, Ni, and dissolute the Cr in the form of metal hydroxide is determined. Acid digestion is done by using H2SO4 and precipitation is done by sodium hydroxide (NaOH). The heavy metals concentrations were determined through inductively coupled plasma-optical emission spectroscopy (ICP-OES). The result showed that the concentration of H2SO4 is significantly affecting the sludge organic content. The respective percentage of Cu, Ni and Cr removed by 30% of H2SO4 were 98.99, 99.27 and 97.22%. At pH 14, Cu, Ni and Cr precipitation to form metal hydroxide was the highest. About 4.01%, 23.75% and 13.93% of copper hydroxide, nickel hydroxide and chromium hydroxide are, respectively, precipitated out. However, slight dissolution occurred due to the nature solubility of metal hydroxide.