Valorisation of mango seed via extraction of starch: preliminary techno-economic analysis

Reducing environmental impacts and obtaining economic benefits based on utilisation of waste materials are drivers for the implementation of cleaner production policies and technologies in food processing industries. Starch is a very versatile material with a wide range of applications in the food, pharmaceutical, textile, paper, cosmetic and construction industries. In Ethiopia, starch is widely used in the textile industry. To meet the starch demand, the country imports approximately 45% of the starch used in the country. Consequently, it is imperative to find additional sources of starch that could substitute for the amount of starch that is currently being imported. Mango seeds, a waste material that is disposed of after consumption of mangos, were studied for potential use as an alternative resource for starch production. The results showed that starch extraction from mango seeds was facile and a good quality product was obtained. The present study is concerned with a techno-economic analysis for industrial production of starch from mango seeds. The study shows that extraction of starch from waste mango seeds is feasible: the project is financially viable with an accounting rate of return of 83% and a break-even analysis of 78% with a payback period of 2 years.     

Valorisation of chicken feathers: a review on recycling and recovery route—current status and future prospects

Worldwide, the poultry meat processing industry generates large quantities of feather by-products that amount to 40 × 10⁹ kg annually. The feathers are considered wastes although small amounts are often processed into valuable products such as feather meal and fertilisers. The remaining waste is disposed of by incineration or by burial in controlled landfills. Improper disposal of these biological wastes contributes to environmental damage and transmission of diseases. Economic pressures, environmental pressures, increasing interest in using renewable and sustainable raw materials, and the need to decrease reliance on non-renewable petroleum resources behove the industry to find better ways of dealing with waste feathers. A closer look at the structure and composition of feathers shows that the whole part of a chicken feather (rachis and barb) can be used as a source of a pure structural protein called keratin which can be exploited for conversion into a number of high-value bioproducts. Additionally, several technologies can be used to convert other biological components of feathers into high value-added products. Thus, conversion of the waste into valuable products can make feathers an attractive raw material for the production of bioproducts. In this review, possible applications of chicken feathers in a variety of technologies and products are discussed. Thus, using waste feathers as a valuable resource can help the poultry industry to dispose of the waste feathers in an environmentally sustainable manner that also generates extra income for the industry. Their valorisation can result in their sustainable conversion into high-value materials and products on the proviso of existence or development of cost-effective technologies for converting this waste into the useful products.     

A New Method for the Analysis of Soluble and Insoluble Oxalate in Pulp and Paper Matrices

A novel method has been developed for determining soluble and insoluble forms of oxalate in pulp and paper samples by ion chromatography. Methanesulphonic acid is used to dissolve insoluble oxalate, and total oxalate is then determined by ion chromatography with suppressed conductivity detection. Soluble oxalate is determined directly by ion chromatography, without prior chemical treatment. Insoluble oxalate is obtained by difference. The method was applied to samples of pulp, process liquors, filtrates, and scale deposits from kraft mills. In kraft mills, considerably higher levels of oxalate were found in the Eop samples compared to those in the brownstock and D₀ samples. In both brownstock and Eop samples, oxalate was mainly present in soluble form, whereas the D₀-stage contained relatively higher levels of insoluble oxalate.     

Thermodynamic measurement and modeling of hydrate dissociation for CO2/refrigerant + sucrose/fructose/glucose solutions

Hydrate dissociation conditions were studied for the CO₂/refrigerant + sucrose/fructose/glucose solution systems as a continuation of previous work into alternate separation technologies for the sugar manufacturing industries. Experimental data were measured following the isochoric pressure method for the CO₂ + sucrose/fructose solution systems. The refrigerants studied for the modeling purpose were R410a, R507, R134a, and R22 using literature data. The pressure and temperature ranges for the experimental data measured here were (1.80–4.10) MPa and (276.6–282.6) K, respectively, with solutions measured in the composition range between 0 to 0.40 mass fraction sucrose and fructose. Several models following the Van der Waals–Platteeuw solid solution theory were developed to predict the hydrate dissociation conditions of CO₂/fluorinated refrigerant in the presence of sucrose/fructose/glucose solutions. The modeling results provide a satisfactory representation of the experimental data, with AARD(P) % model errors in the overall range between 0.03% and 4.40%.     

Data-driven modeling for determination of asphaltene stability condition in oil system

Asphaltene precipitation is accounted as one of the most serious problems during oil production so that it can decrease the production of crude oil and cause the blockage of reservoir rock pores, etc. An accurate prediction of phase behaviour of asphaltene is therefore important in oil production industry. Accurate prediction of phase behaviour of asphaltene precipitation i.e. stability state of asphaltene precipitation in oilfields is greatly desirable. To this end, the applicability domains of the most important variables for the determination of the stability state of asphaltene precipitation viz. aromatic + resin and asphaltene + saturates have been specified by using decision tree (DT) algorithm. Next, adaptive neuro-fuzzy inference system (ANFIS) approach was implemented in order to determine the stability state of asphaltene precipitation using the efficient variables of aromatic + resin and asphaltene + saturates. The results obtained in the current study demonstrate that the models proposed in this study provide desirable results in estmating the stability state of asphaltene precipitation in oilfields.     

Modeling of the Properties of Gasoline and Petroleum Fractions Using a Robust Scheme

Gasoline is one of the most recognized products of the petroleum industry due to its use as a liquid fuel worldwide. As a result, it is of great importance to accurately determine the properties of gasoline, so as to evaluate its quality. In this article, an effective mathematical and predictive strategy, namely least squares support vector machines (LSSVM) is applied to predict some gasoline properties, viz. specific gravity (SG), motor octane number (MON), research octane number (RON), and Reid vapor pressure (RVP). A comprehensive error analysis is also undertaken to compare the values predicted from the model with actual data which enables one to evaluate the performance of the model developed in this study. The results indicate that the model developed has reasonable accuracy and prediction capability. The correlation indices, R², are 0.990, 0.933, 0.955, and 0.920 for SG, MON, RON, and RVP, respectively.     

Valorisation of avocado seeds: extraction and characterisation of starch for textile applications

Sustainable disposal of the waste is problematic due to increasing shortages of landfill space. Avocado is a common fruit that is widely consumed in many countries. This consumption results in large quantities of avocado waste being generated by the avocado processing industries. However, avocado seeds contain large amounts of starch that could be beneficiated. Starch is widely used in various industrial applications and is routinely sourced from food crops, thus competing with traditional sources of food. Alternative non-food sources of starch are needed. This work focused on ascertaining the cleaner way of extracting starch from avocado seeds for use in industrial applications. The starch was extracted from avocado seeds via a wet extraction method and tested for application in the textile industry. Optimal conditions for the extraction of starch were determined using statistically designed experiments employing a Box–Behnken design and Statistica 13 software for the experimental design, statistical analysis and optimisation of the extraction process. The analysis of variance results revealed that a quadratic model is significant for the factors and responses studied. A quadratic mathematical model was developed, and the optimum combination of a response factor was obtained by the simultaneous optimisation of the responses. The starch yield was 64% (on dry weight basis). Analysis of the extracted starch showed that it contained well over 90% starch content. Application of the starch in textile applications showed that it performed as well as a commercial starch sample. The collection and processing of waste avocado seeds can be a new source of employment and provide income generation opportunities.     

An insight into thermodynamic consistency of hydrogen sulfide sulfur content data at isobaric conditions

In this work, a thermodynamic consistency test method was used to investigate the reliability of isobaric experimental data on the sulfur content of hydrogen sulfide. The test was applied to literature data. A thermodynamic model based on the Peng-Robinson equation of state with conventional mixing rule was used for prediction of sulfur (S8) deposition from hydrogen sulfide vapor phase. The data considered was analyzed to determine whether it was thermodynamically consistent (TC), not fully consistent (NFC), or thermodynamically inconsistent (TI). The results show that the experimental data for the sulfur content of hydrogen sulfide are thermodynamically consistent.     

Beneficiation of pulp and paper mill sludge: production and characterisation of functionalised crystalline nanocellulose

The beneficiation of sludge from pulp and paper mills to produce high-value products such as crystalline nanocellulose will alleviate the challenges associated with conventional methods of sludge disposal, such as landfilling and incineration. In addition, the use of sludge will reduce the consumption of fresh raw materials in the synthesis of nanocellulose which is usually produced from high-purity cellulose pulps. In this study, fibres were cleaned and separated from sludge and then converted to crystalline nanocellulose using ammonium persulphate under optimised oxidative conditions. To extend potential applications of the crystalline nanocellulose produced, the crystalline nanocellulose was functionalised with zinc oxide, silver and hydroxyapatite to prepare crystalline nanocellulose-zinc oxide, crystalline nanocellulose-silver and crystalline nanocellulose-hydroxyapatite nano- and micro-composites powders using the sol–gel process. Transmission electron microscopy, field-emission scanning electron microscopy, X-ray diffraction and thermo-gravimetric analysis were used to investigate the properties of crystalline nanocellulose and functionalised crystalline nanocellulose. The transmission electron microscope and field-emission scanning electron microscope coupled with energy-dispersive X-ray spectroscopy confirmed the synthesis of crystalline nanocellulose, and inorganic nanoparticles. Functionalised samples (crystalline nanocellulose-zinc oxide, crystalline nanocellulose-silver and crystalline nanocellulose-hydroxyapatite) showed better thermal stability than pure crystalline nanocellulose. This implies that the modified inorganic crystalline nanocellulose composites could be used in applications where thermal stability is desirable. The cost of production is economically viable as the raw material cost is cheaper compared to the use of wood pulp.     

Development of a LSSVM-GC model for estimating the electrical conductivity of ionic liquids

In this communication, an extensive set of 1077 experimental electrical conductivity data for 54 ionic liquids (ILs) was collected from 21 different literature sources. Using this dataset, a reliable least square support vector machine-group contribution (LSSVM-GC) model has been developed, which employs a total of 22 sub-structures in addition to the temperature to represent/predict the electrical conductivity of ILs. In order to distinguish the effects of the anion and cation on the electrical conductivity of ILs, 11 sub-structures related to the chemical structure of anions, and 11 sub-structures related to the chemical structure of cations were implemented. The proposed model produces a low average absolute relative deviation (AARD) of less than 3.3% taking into consideration all 1077 experimental data values.