Maize Cob Research Articles

Nepenthes mirabilis Fractionated Pitcher Fluid Use for Mixed Agro-Waste Pretreatment: Advocacy for Non-Chemical Use in Biorefineries

This study determined whether it is feasible to pretreat mixed agro-waste of different particle sizes using the pitcher fluid of Nepenthes mirabilis (N. mirabilis), which is known to digest leaf litter due to the enzyme cocktail contained in the fluid. This is due to the need for the holocellulolysis (a source of fermentable sugars) of mixed agro-waste to produce fermentable hydrolysates. The pitcher fluid was fractionated (<3 kDa, >3 kDa, <10 kDa, >10 kDa) and slurrified with the mixed agro-waste, i.e., 25% (w/w) for each waste—orange peels, apple peels, maize cobs, grape pomace, and oak plant leaf litter of various particle sizes, i.e., >75 µm x < 106 µm and >106 µm. The process of producing a high concentration of total reducible sugars (TRSs) with the lowest production of total phenolic compounds (TPCs) was determined to be a particle size of >106 µm, pretreatment for 72 h, and an enzyme fraction of <10 kDa, whereby 97 g/L of TRSs were produced with a significantly lower TPCs load (1 g/L). Furthermore, the <10 kDa showed preferable physico-chemical properties, with the highest reduction-oxidation potential including acidity. Several enzymes, i.e., β-1,3-Glucanase, Putative peroxidase 27, Thaumatin-like protein, among others, were identified in the <10 kDa fraction, i.e., enzymes known to perform various functions in plant-based waste. Therefore, there is a need for the renewable energy industry to consider solely using pitcher fluids to pretreat mixed agro-waste for fermentable hydrolysates’ production, which can be used as liquid feedstock for the bioenergy and/or biorefinery industries for environmental pollution reduction.

Assessment of Different Biochar and Composted Cow Dung on Soil Properties, Growth and Cob Weight of Maize

Crop production in tropical soils is constrained by low fertility. The scarcity and high prices of chemical fertilizers have added to the existing challenges. This study examined the influence of different types of biochar and cow dung compost (CDC) on soil properties, growth and cob weight of maize. A polythene pot experiment was conducted at the screen house of the Institute of Ecology, Obafemi Awolowo University, Ile-Ife, Nigeria. The experiment was laid out in a completely randomized design. Amendments used were: cow dung compost, cow dung biochar and maize cob biochar, which were applied singly at the rates of 0, 4, 8, 12, 16 t.ha-1. The production of biochar from cow dung compost and maize cobs was done using a local charcoal-fired reactor. The feedstocks were slowly pyrolyzed at 350 0C and removed after 3hrs. The treatments were replicated twice. Soils amended with CDC had the highest growth parameters compared to other amendments. In the first season, CDC had a 22% increase in height compared to MCB. CDC had a height of 72 cm while MCB had the lowest height with 56 cm. The growth rate was as follows: CDC > CDB > MCB. CDC also increased cob weights when compared to other amendments. At 4 t ha-1, CDC had 2.20 g, CDB had 0.90 g while MCB had 0.47 g. Significant differences were observed among the treatments. However, it was observed that CDB increased soil chemical properties compared to other amendments. Soil properties such as organic carbon and total nitrogen were significantly improved in soils treated with CDB. This study concluded that cow dung biochar was better suited to improve soil properties while also improving crop growth compared to other amendments.

Maize grain yield responses to realistic biochar application rates on smallholder farms in Kenya

Despite efforts to increase agricultural production sustainably in sub-Saharan Africa, large gaps remain between actual and potential yield of food crops. Adding biochar to degraded cropland soils in the African tropics has significant potential to enhance crop productivity. Biochar-based farming can also mitigate climate change, through soil carbon storage. This study involved six smallholder farms at sites in eastern, central, and western Kenya that are characterized by different pedo-climatic conditions. We examined the response of non-fertilized and fertilized maize monoculture to three dosages of biochar that are realistic for domestic production by farmers at each of the sites over four growing seasons. Commonly available biomass wastes in each agro-ecosystem (coconut shells, coffee husks, maize cobs) were used as feedstock for biochar, which was applied at 1, 5, and 10 Mg ha−1 at the start of the experiment. Across seasons and fertilizer treatments, maize grain yield (dry matter) showed consistently positive responses, with an average increase of 1.0, 2.6, and 4.0 Mg ha−1, respectively, above the control for the three biochar application rates. Absolute responses of maize grain yield to specific biochar doses were similar across the four investigated seasons and replicate farms within sites, and uncorrelated to yield levels in the control treatment. Here, we show for the first time that yield response to biochar decreased with increasing application rate, indicating that it may be better to spread a given amount of biochar over a large area rather than concentrating it to a smaller area, at least when biochar is applied along plant rows at rates ≥1 Mg ha−1, as in our experiment. This study demonstrated that application of biochar, locally produced from available biomass residues, is a promising approach to enhance agricultural production and carbon storage on smallholder farms under a wide range of pedo-climatic conditions in Kenya.

Effect of Fungal, Bacterial and Alkaline Augmentations on the Biogas Composition of Selected Plant-based Substrates

Lignocellulosic residues are interesting sources of renewable energy, if only their biomass recalcitrance could be reduced through appropriate pretreatment technologies and augmentations, to enhance anaerobic digestion. This study aimed at assessing the effects of bacterial, fungal and alkaline augmentations, on the biogas composition of selected plant-based substrates, namely: maize cob , rice straw and water hyacinth. Standard methods were adopted; the substrates were mechanically pretreated, loaded in single, dual and composite combinations, into five 54 L capacity metallic batch anaerobic digesters. Codigestion was encouraged with the addition of cow rumen waste. The set ups were allowed to run for 42 days under mesophilic conditions, while stirring daily. The biogas composition namely: methane, carbon IV oxide and hydrogen sulfide concentrations were measured on the 42nd day. The results showed that the composite with the combined treatments showed the highest concentration of methane (87%), followed by the composites with fungal augmentation (80%), bacterial (77%) and then alkaline (75%) augmentations. The least percentage of methane (9%) was recorded in the composite without treatment and no cow rumen waste added, which also had the highest percentages of hydrogen sulphide and carbon IV oxide. To improve the yield and quality of biogas generated from a lignocellulosic biomass, appropriate pretreatment strategies and augmentations are required.

Effects of Biochar on Soil Fertility and Crop Yields: Experience from the Southern Highlands of Tanzania

The world’s agricultural production is declining due to severe loss of soil fertility through natural processes or because of human activities. Biochar has been identified as a potential soil amendment to regain its fertility and increase crop productivity. This study aimed to assess the effects of biochar on soil nutrients and crop yields in the southern highlands of Tanzania. Data were collected through key informant and household interviews, and from sampling of soils in coffee farms where biochar of maize cobs origin was incorporated at the rate of 3 t ha-1. Purposive sampling approach was deployed to identify the villages in which farmers have been incorporating biochar in farms. A total of 172 households, 30 key informants, and 12 top and subsoil samples were involved in this study. Quantitative data were analyzed using SPSS version 20, and excel spreadsheet was used for descriptive results and relationships. The findings revealed that biochar significantly increased soil pH, iron (Fe), organic carbon (OC), cation exchange capacity (CEC) and exchangeable bases (potassium-K, magnesium-Mg). T - tests showed significant increase of soil nutrients in biochar treated soils. In addition, biochar increased coffee and maize yields from 1 t ha-1 to 3 t ha-1.
 Keywords: Biochar; Soil Nutrients; Food Security; Resilience; Adaptation

Synthesis of mesoporous akaganeite functionalized maize cob biochar for adsorptive abatement of carbamazepine: Kinetics, isotherms, and thermodynamics

In this work, akaganeite (β-FeO(OH)) impregnated maize cob biochar (Fe-MCB) was prepared by direct hydrolysis, and its adsorptive potential was tested against aqueous solutions of carbamazepine (CBZ), an emerging contaminant. The adsorbent was characterized by standard methods, namely XRD, SEM-EDX, FT-IR, BET surface area analysis, and VSM. Fe-MCB exhibited mesoporous textural structure with paramagnetic behavior at room temperature. The equilibrium data were modeled using the Langmuir, Freundlich, Fowler-Guggenheim and Sips isotherm models. The adsorption data were best described by Fowler-Guggenheim with an estimated maximum adsorption capacity of 81.80 mg g−1. The adsorption rate was described by the pseudo-first-order (PFO) model. The thermodynamic functions, namely enthalpy (ΔH = -6.88 kJ mol−1), negative Gibbs free energy (ΔG) values, entropy (ΔS = 26.33 J mol−1), indicated that the adsorption was exothermic, spontaneous, with the increased disorder at the solid-liquid interphase. The adsorption mechanism is thought to entail dispersive interactions. Modified maize cob biochar is a potentially techno-economic sorbent for CBZ adsorption.

Influences of a novel cylindrical solar dryer on farmer's income and its impact on environment.

Poor grain drying facilities, along with the burden of drying cost, bound the farmers to market their produce soon after harvest. Thus, this research paper intends to study the influences of a novel cylindrical solar-assisted dryer on farmers' income and its impact on the environment. The paper also presents the design and fabrication of a drying system for maize cobs using non-conventional solar energy. The performance of the solar-assisted drying system was also investigated for drying of yellow dent maize cobs. As a very energy-intensive post-harvest process, drying consumes a lot of electricity, which is usually provided by conventional energy. Here, solar dryers are the perfect solution in terms of efficiency, uniform drying of agricultural food products, less drying time, increased marketability of agricultural products, and reducing the load on farmer's pocket for drying. With a high internal rate of return of 66 percent, the designed dryer proved to be technically and economically viable. Compared to open sun drying, the solar drying system produced better quality and drying time results. Compared to other models, the Midilli model fits the experimental maize drying data better, with a coefficient of determination of R2 = 0.89729. Energy analysis inferred savings of 1352.97 kWh electrical energy and 128.18 liters of diesel fuel plus a reduction of 1.22 t CO2 per annum can be achieved by using this dryer.

Kinetics, Isotherm and Thermodynamic Studies of the Reclusion of Cu (II) from Aqueous Solution by Maize Cob and Sugarcane Pulp

Over the years, heavy metal contamination of the environment, through industrial waste had been a perennial problem to which biosorption is being proposed as solution in recent studies. The biosorption characteristics of Cu (II) ion using maize and saccharumofficinarum (sugarcane pulp) were investigated by contacting 0.5g of the biomass with 10ml of 100mg/L solution of the metal ions. Experimental parameters affecting the biosorption process such as pH, contact time, concentration and temperature were studied. Langmuir and Freundlich models were applied to describe the biosorption isotherms. The biosorption capacities of maize cob and saccharumofficinarum were found to be sufficiently high to consider the biomasses used as substances that could be employed in the removal of Cu (II) ions from waste water. The calculated thermodynamic parameters, G 0 , for biosorption of Cu (II) on to cob and bagasse determine at pH 5.0 and 301k, are -1.5KJmol -1 and -2.505KJmol -1 respectively. This showed that the biosorption of Cu (II) ions onto maize cob and saccharumofficinarum was feasible and spontaneous at 301K.

Influence of Simultaneous Intercropping of Maize-Bean with Input of Inorganic or Organic Fertilizer on Growth, Development, and Dry Matter Partitioning to Yield Components of Two Lines of Common Bean

Intercropping is a common practice among smallholder farmers cultivating common bean (Phaseolus vulgaris L.) and maize (Zea mays L.). It affects agronomic performance, dry matter partitioning, and grain yield. Simultaneous intercropping of common bean with maize can influence growth, development, and dry matter partitioning of grain of common bean. The main objectives of this study are to: (i) evaluate the dynamics of growth and development of the different vegetative organs, and (ii) determine the efficiency in dry matter partitioning to yield components of two common bean lines grown under monoculture compared with two simultaneous intercropping patterns (pattern 1, pattern 2) with maize and managed with two types of fertilizer application. A randomized complete block design (RCBD) with 3 replications was used in a nested trifactorial arrangement in split-plot scheme. The field experiment was conducted in two seasons under conditions of acid soils and high temperatures in the western Amazon region of Colombia. Simultaneous intercropping patterns 1 and 2 had a negative effect on growth dynamics of maize compared to maize monoculture. But the two bean lines when associated with maize showed no significant differences on growth dynamics under both types of fertilizer application. Under both intercropping patterns, the maize cobs were larger, a condition that increased the number of grains, but with smaller size of grains compared to monoculture. In the case of two bean lines, the growth and development responses were different: under monoculture the number of pods and seeds per plant was higher while the number of grains per pod increased under intercropping patterns. Among the two bean lines, 100-seed weight was significantly higher in BFS 10 compared to ALB 121. At the grain yield level of common bean, the simultaneous intercropping pattern increased 516 kg ha−1 and 993 kg ha−1 more than that obtained in monoculture (4936 kg ha−1) with inorganic and organic fertilizer, respectively. Results from this study indicated that smallholders in the Amazon region of Colombia can achieve higher grain yield through the implementation of simultaneous intercropping of maize with common bean line (BFS 10) under organic fertilizer application.

Evolution of agricultural wastes for the cultivation of edible mushroom Pleurotus eryngii

This research studies the possible use of some of Iraq's local agricultural wastes as growth substrates for producing the edible oyster mushroom (Pleurotus eryngii). The biological process of growing and producing edible mushrooms is a bioconversion of organic wastes to bioprotein (mycoprotein). Therefore, this study aims to investigate nine different substrates from plant residues. The three primary substrates are typical viz date palm waste (Phoenix dactylifera), maize cob (Zea mays) and cane (Phragmites communis), with two types of additional enrichment, i.e., rice husks (Oryza sativa) and corn seeds husks (Zea mays), and without further enrichment (control). The experiment was randomly distributed according to Randomized Complete Design (RCD), with three replicates. The less crop cycle period (day) which in Treatments T7 and T8 (30.33, 31.67 days) when T2 (100%Corncobs), T1 (100%Waste of Date palm), T7 (80%Waste of the date palm with 20%Corn husks) and T8 (80% Corncobs with 20%Corn husks) provide the crest mushrooms yield arrived 293.0 280.7, 268.7 and 264.0 g kg-1 substrate respectively. Keywords. Bio protein; lignocelluloses; Mushroom substrates; Oyster mushrooms

Determination of the effect of quantity of maize cobs and shelling speed on the performance of a maize sheller

Arable farming of maize is the most common of all crops in Sub-Saharan Africa. Most often, the processing is done domestically using manual effort, but on few occasions some part are done visiting commercial mechanized processors. This work presents the evaluation of the performance of a maize sheller scaled for domestic use. Three set of maize input (2kg, 3kg and 5kg) were each tested at different shelling speed of 2500 rpm, 2600 rpm and 2800 rpm respectively. The output parameters measured were; shelled maize, unshelled maize, cylinder loss and spilled loss. Subsequently, shelling capacity, cylinder loss (%) and spilled loss (5) were determined. It was however discovered that the 5kg shelling at 2600 rpm gave the highest shelling capacity at 24. This is in agreement with the assessment of the machine when 10kg maize was shelled at 2600 rpm.

EFFECT OF THREE FEEDSTOCKS MIX ON BRIQUETTES’ PHYSICAL AND COMBUSTION PROPERTIES

Significant quantities of biomass are available in Africa for conversion into domestic energy sources. However, they are underutilized due to poor physical and combustion properties. Knowledge about the effect of briquettes with three feedstocks has not been fully studied. Thus, the main objective of this study was to assess effect of three feedstocks mix on briquettes’ physical and combustion properties. The feedstocks; rice husk- maize cobs and bagasse were carbonized in a drum kiln and mixed at different ratios (1:1:1, 1:2:2, 1:3:3, 2:1:2, 2:2:3, 2:3:1, 3:1:3, 3:2:1 and 3:3:2) before densification using screw press technique. Briquettes were sampled for Laboratory testing. At the optimal ratio, 3:2:1, physical properties; moisture content and density values were 6.43% and 904 kg/m3 respectively. Results showed values of 3.63% for ash content, 18.56% for volatile matter, 77.81% for fixed carbon and 29.04 MJ/kg for calorific value. Number and type of feedstocks are thus factors influencing physical and combustion characteristics of briquettes in converting agricultural wastes to useful energy application. Findings from this study are therefore useful to briquettes users, as a source of clean energy, in making right choices on feedstocks mix ratios during densification thus realization of Sustainable Development Goal (SDGs #7).

An economical source for peroxidase: maize cobs

According to the current situation of peroxidase (POD), the relevant studies on this enzyme indicated its importance as a tool in clinical biochemistry and different industrial fields. Most of these studies used the fruits and vegetables as source of this enzyme. So that in order to couple the growing requirements for POD with the recent demands for reduc-ing disposal volume by recycling the plant waste, the aim of the present study was to extract POD through management of municipal bio-waste of Iraqi maize species. A simple, green and economical method was used to extract this enzyme. Our results revealed that maize cobs are rich sources of POD, where the activity of this enzyme was found to be 7035.54 U/g of cobs. In pilot experiments this enzyme was extracted from the cobs using an efficient extraction buffer with either Cetyl Trimethyl Ammonium Bromide (CTAB), or sonication. To purify the extracted enzyme the previous step was followed by aqueous two phase extraction (ATPE) using 20% (w/v) polyethylene glycol (PEG) and 9% (w/v) ammonium sulfate. The obtained results indicated that POD was partially purified with 2.36 fold of purification and 81.78% recovery. The optimum temperature and pH of the extracted POD activity as well as the enzyme thermal stabil-ity were determined and found to be 20°C, pH 6, and stable at 60°C for 10 minutes respectively. Out of the present study findings, it can be concluded that maize cobs are rich source for POD and the applied protocol could be poten-tially used for POD extraction with high level. Meantime, this study suggested a new strategy by which the environ-mental pollution results from accumulation of plant waste can be reduced.

The adsorption of Tenofovir in aqueous solution on activated carbon produced from maize cobs: Insights from experimental, molecular dynamics simulation, and DFT calculations

The aim of this work is to evaluate the adsorption of Tenofovir using activated carbon (ACc) produced from local maize cobs by the thermochemical activation method with phosphoric acid (H3PO4). The ACc proprieties were evaluated using a variety of methods, including Fourier Transform Infrared Spectrometry (FTIR), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), X-Ray Diffractometry (XRD), and Thermogravimetric Analysis (TG/DTG). The prepared ACc was also subjected to physicochemical tests such as humidity level, ash content, volatile matter, iodine value, and point of zero charge (pHpzc). The kinetic studies showed that the adsorption data followed a second-order reaction. Meanwhile, the experimental isotherms analysis demonstrated that the Langmuir isotherm fits well the adsorption data with a maximum adsorption capacity (Qmax) of 145.194 mg g−1. The thermodynamic parameters demonstrate an exothermic and spontaneous behavior. An experimental combination of Response Surface Methodology (RSM) with Box-Behnken Design (BBD) was used to optimize the three adsorption principal parameters (pH, dose of ACc, and initial Tenofovir concentration). The results showed that maximum adsorption of 95.13% was achieved at a pH of 4.33, an initial Tenofovir concentration of 0.1 mM, and a mass of ACc of 1 g L-1, however, the desorption was favored in a basic pH (pH ≥ 12). Density functional theory was used to study the global and local quantum descriptors and the interaction energy between the Tenofovir and the ACc surface. Monte Carlo simulation was used to calculate the adsorption energy of the adsorption process between Tenofovir and the ACc. Theoretical results revealed that Tenofovir has strongly interacted with the ACc, which supports the experimental results.

Effect of Cinnamon Powder Supplementation with Diets Containing Maize Cobs and Sugarcane Pulps/Peels on In-Vitro Methane Emission and Performance of Goats

The study was conducted to examine the effects of cinnamon powder as additive in diets containing maize cobs and sugarcane pulps/peels on in-vitro methane production and performance of goats using a completely randomized design. The basal and each of the supplementary diets that were used in a ratio of 60: 40 in treatment diets D1, D2, D3 and D4 contained 0%, 1%, 2% and 3% on dry matter basis of cinnamon powder inclusion respectively in the study. About 200mg of each of the diets in three replicates with a mixture of medium solution and rumen liquor (2:1) were used for in-vitro methane emission. Thirty-two West African dwarf goats of about 7 to 8 months of age with average body weight of 7.00 ± 0.80kg were randomly assigned to the four treatment diets. The experiment lasted for 84 days. Data obtained on in-vitro gas production, live-weight gain, digestibility and nitrogen retention variables were analysed using inferential statistics that was one-way analysis of variance. Results showed that gas production, methane emission, substrate degraded, neutral detergent fibre degradation, ether extract digestibility, nitrogen intake, faecal with urinary nitrogen output and feed conversion ratio were significantly (p<0.05) higher in diet D1 than other diets. Feed intake, live weight gain, digestibility of dry matter, crude protein, crude fibre with nitrogen free extract and nitrogen retention were significantly (p<0.05) better in diet D3 as compared with diets D1, D2 and D4. Reduction in methane gas production was best in D3. In conclusion, the use of 2% cinnamon powder as additive to diet containing 22% maize cobs and 19% sugarcane pulps/peels enhanced performance in goats

Effects of different substrates on production of oyster mushroom in walling of syangja, Nepal

This research was conducted in Agriculture Development Resource Center, Syangja to determine the effectiveness of substrate for the production of oyster mushroom (Pleurotus ostreatus). Completely Randomization Design was used for this research with three replications in which five treatments (substrate) were used i.e.; rice straw, finger-millet straw, saw dust, maize straw and maize cob. Days required for full colonization, first fruiting, harvesting time, total mushroom production, mushroom pileus diameter, and stipe length were observed by taking 5 sample randomly from each treatment. Among the investigated substrate compositions, maize cob required the fewest days (19 days) to complete spawn running, followed by finger-millet straw (21 days), while saw dust required the most days (38 days) to complete spawn running. Finger-millet straw indicated the shortest time (28 days) harvesting, and the maximum yield was found in finger-millet straw (1.05 kg) and highest stipe length (5.3cm) was found in saw dust followed by rice straw (4.8 cm). Among various used substrate finger-millet straw was found to be the best for mushroom production at least in Waling, Syangja.
 Res. Agric., Livest. Fish.9(1): 11-16, April 2022

NUTRITIONAL QUALITY OF TREATED MAIZE COB AND HUSK IN A COMPLETE DIET BY WEST AFRICAN DWARF GOATS

The study was conducted to investigate the chemical composition of untreated and microbial treated maize cob and husk and digestibility of treated maize cob and husk in a complete diet by West African dwarf goats. Three goats per treatment were allotted to six dietary treatments in a completely randomized design. The chopped maize cobs and husks were sterilized for 60 minutes, inoculated with mixture of 15 ml each of Neurospora crassa and Lactobacillus delbrueckii, incubated for 5 days and air dried. The treated maize cob and husk were incorporated in the diets at the rate of 0 % (diet A), 20 % (diet B), 30 % (diet C) [maize cob diets], 0 % (diet D), 20 % (diet E), 30 % (diet F) [maize husk diets] respectively. The digestibility trial lasted for 21days. Chemical composition results showed that dry matter improved from 84.85 – 86.95%, protein from 7.00 -9.01% and the crude fibre reduced from 30.45 – 20.05 % for maize husk and dry matter from 82.27- 84.45%, protein (3.56 -6.79%), crude fibre (33.66 -22.15%) for maize cobs. Significant differences (P<0.05) were observed in the nutrient digestibility as superior crude protein digestibility (82.93%) was observed in goats fed diet containing 30% treated maize husk. Conclusively, microbial treatment of maize cob and husk enhanced the dry matter, protein and considerably reduced the fibre fractions of the treated samples as well as improved digestibility.

Synthesis, Characterization, and Evaluation of the Remediation Activity of Cissus quadrangularis Zinc Oxide Nanoparticle-Activated Carbon Composite on Dieldrin in Aqueous Solution

In this study, zinc oxide-activated carbon nanocomposite was used as the adsorbent for the remediation of dieldrin in aqueous media. Zinc oxide nanoparticles (ZNPs) were synthesized from Cissus quadrangularis (C. quadrangularis) leaf extract, and activated carbon was derived from maize cobs. Nanocomposites were formulated by mixing the ZNPs with the activated carbon in a ratio of 1 : 50. The UV-Vis spectra showed a complete reduction of Zn2+ to Zn0 with plasmon resonance bands in the range of 361–376 nm, which is a characteristic of ZNPs. The SEM images of ZNPs showed hexagonal-shaped particles of 15–20 nm, with face-centered cubic crystals, as demonstrated by XRD analysis. FTIR results showed absorption bands in the ranges 3500–3100 cm−1 (N-H stretch), 3400–2400 cm−1 (O-H stretch), 988–830 cm−1 (C-H bend), 1612 cm−1 (C=C stretch), 400–600 cm−1 (Zn-O stretch), and 1271 cm−1 (C-O bend). Batch adsorption experiments were performed using 20 ml of dieldrin solution at varying pH values (1–14), concentrations (5–100 ppm), temperatures (293–323 K), adsorbent dosages (0.01–0.12 g), and contact times (30–180 minutes) to determine the optimum conditions. The calculated thermodynamic parameters (ΔH°, ΔS°, and ΔG°) indicated that the adsorption was spontaneous and exothermic in nature, implying decreasing randomness of dieldrin molecules at the solid-liquid interface. The isotherm and adsorption kinetics for the composite showed that the absorption process followed Langmuir isotherm and pseudo-second-order kinetics. Adsorption capacities of the nanoparticles, activated carbon, and nanocomposite at a reaction time of 120 minutes and pH of 7 were 3.72 ± 0.068 mg/g, 3.92 ± 0.061 mg/g, and 4.0 ± 0.102 mg/g, respectively, with corresponding percentage removals of 93.12 ± 0.044, 98.04 ± 0.044, and 99.76 ± 0.332. Thus, the nanocomposite exhibited a better sorbing potential for dieldrin in solution than activated carbon. This study recommends testing the remediation potential of the synthesized nanocomposite on other persistent organic pollutants.

Viability of some African agricultural by-products as a feedstock for solid biofuel production

As a source of renewable energy, agricultural by-products after pre-processing and cleaning in post-harvest lines can be used as a feedstock for the production of pellets or briquettes. This can be achieved by determining the physicochemical properties of the by-products. Groundnut pods, maize cobs and the husks of rice, millet and sorghum were considered, and their properties were determined, which were then compared with the standard properties of pellets and briquettes to ascertain their viability as a feedstock for the pellet or briquette production. The by-products were transported from Nigeria to the Czech Republic and the research was carried out at the Department of Technological Equipment of Buildings, the Faculty of Engineering, Czech University of Life Sciences Prague. The moisture content, ash content, calorific value, nitrogen content and sulfur content were the properties considered of the by-products. Groundnut pods and maize cobs with a calorific value of 17.48 MJ·kg–1 and 16.25 MJ·kg–1, an ash content of 3.46% weight and 1.79% weight, a nitrogen content of 1.24% weight and 0.44% weight and a moisture content of 7.92 weight and 7.56% weight, respectively, were discovered to fulfill all the requirements for graded non-woody pellets A. With the exception of rice husks and millet husks, which were discovered to have high ash contents and low calorific values, all the by-products fulfilled the standard requirements for one or more grade of pellet/briquette. They can, therefore, be used as a good feedstock for pellet or briquette production.

Comparison of acid and alkaline pre-treatment of lignocellulosic materials for biogas production

This work deals with the study of a pre-treatment method promoting degradability of lignocellulosic biomass and hence biogas yield therefrom, as this material is challenging to decompose due to its structure. The investigated pre-treatment methods are hydrolysis of the material in NaOH (0.5% and 5%) and H<sub>2</sub>SO<sub>4</sub> (0.5% and 5%) at temperatures of 90–100 °C for 2 h. This work aimed to compare the effects of these pre-treatment methods on the lignocellulosic composition of maize waste (maize stalks, leaves and cobs), rapeseed straw and wheat straw and the biogas yields from its subsequent anaerobic digestion. Pre-treatment by 0.5% NaOH increased the biogas production the most (by 159% for rapeseed straw, 240% for wheat straw and 59% for maize waste) also the degrees of solubilisation was higher, at the same time the proportions of total organic carbon (TOC) in the solid component appear to be sufficiently high, it could be assumed that there has been sufficient disturbance of the material structure. Alkaline methods have proven to be more suitable compared to acid pre-treatment methods, also the use of alkali with a lower concentration has shown to be more efficient, which is more advantageous for use in practice from an environmental and economic point of view.