The effect of reaction variables on the uptake of heavy metals from wastewater using modified chitosan and plantain peels carbon based adsorbents was explored in this study. Plantain peels were carbonized, activated with phosphoric acid and the activated carbon was separated into various proportions and impregnated with various percentages of chitosan to make the composite biosorbents. Deproteinization, deminerization, and deacetylation techniques were used to extract chitosan from a snail shell. Fourier transform infrared (FTIR), energy dispersive X-ray (EDAX), X-ray diffraction (XRD), scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) techniques were used to analyze the adsorbents. Effects of process parameters: pH of wastewater, adsorbent dosage, temperature, initial concentration and contact time were determined. In the blending ratios of the biosorbents, 75% oxalic acid modified chitosan-25% activated plantain peel (CHT-APP5) was best blend and the optimum process variables for the removal efficiency were time (60-65mins), adsorbent dosage (2-2.125g/dm3), pH(6-6.5), initial concentration of wastewater(20-85mg/dm3) and temperature (308-325K). The results obtained showed that the maximum adsorption capacities of 90.9090, 55.5556 and 142.8571mg/g for Cr(VI) while 62.500, 83.3333 and 43.4783mg/g Cd(II) were obtained for CHT, APP1 and CHT-APP5 respectively. The results showed that blends have the potential to be used as alternative efficient low-cost biosorbent in the removal of heavy metals from wastewater.

The performance of peroxidated powdered fibers of corn stover and sugarcane bagasse as fillers in natural rubber was evaluated in this study. Powdered corn stover and sugar bagasse fibers were subjected to the conventional peroxidation treatment for conversion to more hydrophobic fillers with enhanced tensile properties. The physicochemical properties of the peroxidated fibers were assessed using standard methods. Morphological properties, thermal stability, and functional groups were also assessed. The treated and untreated fibers were then used as fillers in natural rubber compounding using the two-roll mill, compression moulding and subjected to physico-mechanical characterization. There was improved dispersion of the peroxidated fibers in the polymer matrix, which meant significant improvement in the reinforcement and mechanical properties of the natural rubber compounds. A morphological study of the composites showed that natural rubberperoxided fiber composites have very good dispersion in the rubber matrix. The mechanical properties showed that the composites have improved properties with the highest tensile strength of 44.55 MPa, modulus at 100% elongation of 6.11 MPa, elongation at break of 294%, hardness of 74.30 IRHD.

In this study the impact of feedstock-to-inoculum ( F / I ) ratio in dry anaerobic digestion (DAD) of Hura crepitans leaves was evaluated. Measured biogas volumes, as well as the chemical kinetic predictions for exponential, logistic and Gompertz model, depicting the agreement of the simulations over time, were also determined. The digesters were codenamed DAD2, DAD4 and DAD6 based on their F / I ratios 2, 4 and 6 at 22% total solids. Digester DAD4 was the most promising in terms of biogas production with daily biogas production of 235 ml while the cumulative biogas production was 2200 ml. On the other hand, digester DAD6 with the F / I ratio 6 recorded the lowest cumulative biogas production of 615 ml. Early commencement of biogas production in all the digesters was indicative of a good start-up phase, which is one of the challenges often encountered in DAD process. Furthermore, kinetic studies revealed a direct correlation between biodegradability constants and biogas production. The kinetic models studied revealed that logistic and Gompertz models performed better than the exponential model.

The sorption efficiency of bones and neem leaves adsorbents for the removal of cadmium ions from wastewater was investigated in the study. The animal bones and neem leaves were carbonized and activated using phosphoric acid. The adsorbents were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, x-ray diffractometry and atomic absorption spectrometry. The equilibrium sorption properties were assessed to optimize the conditions for maximum sorption of the cadmium ions. As for the samples of neem leaves, it was observed that the activated carbon prepared from neem leaves had a high adsorption efficiency of 73.13% than that of raw neem leaves of 67.53% and activated leaves having the lowest efficiency of 25.49%. From the values obtained for animal bones, the carbonized sample had the highest efficiency of 75.22% and the raw sample had high efficiency of 74.23%.

The assessment of zinc oxide – reduced graphene oxide hybrid filler in natural rubber was carried out in this study. The modified Hummers’ method was used to prepare the graphene oxide (GO) from which the reduced graphene oxide (rGO) was synthesized and hybridized with zinc oxide in a two-step process. The resulting ZnO/rGO hybrid filler was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectrophotometry (FTIR), thermogravimetric analyzer (TGA), and X-ray diffraction (XRD). The natural rubber/ZnO/rGO composites were produced by compounding based on formulations using a two-roll mill. The performance of the hybrid filler in the natural rubber composites was carried out by assessing the tensile properties, Hardness test, compression set, abrasion resistance and sorption properties in different solvents. The mechanical properties showed that NR/ZnO/rGO nanocomposite exhibited improved properties with tensile properties of 25.85 MPa, modulus at 100% elongation of 8.78 MPa. NR/ZnO/rGO composite showed the least elongation at break 445.51 %. The highest properties value was observed with NR/ZnO/rGO composite hardness 59.40 IRHD, Compression set 13.31%, abrasion resistance 45.84 mm3/rev; energy at break 6.29 N.mm2, and force at break 188.52 N. The results were attributed to the capacity of the ZnO particles to display as a ‘connect’, interfacing with the elastomer by means of electrostatic forces/hydrogen bonding with the rGO by a p–π stacking/electrostatic bond. The mole percent results of the solvents for the hybrid filled composite when compared with the control showed a critical sorption decrease by 41.67% for the kerosene, 4.44% for diesel, 50 % for PMS and water. This showed the capacity of the filled composites to resist solvent sorption and resultant chemical attack. The observed mechanical properties and sorption properties of the composite revealed the applicability of the material for packaging.

The valorization of rubber seed shell into useful materials for industrial applications in polymer technology is of great interest. The usefulness of this material is borne out of the ease of processing; it’s readily available at low or no cost, and less abrasive to equipment. Literature and research reports have shown that rubber seed shell has gained applications in the adhesive industry as reinforcing additive, in electrode manufacturing, as filler in polymer composites, as sorbent in the uptake of heavy metals during waste water treatments, as starting material in the production carbon materials for value added products for the industry. However, there are still outstanding prospects in the utilization of this material in various areas of polymer technology such as a lignocellulosic source for the production of biodegradable foams, polymer gels, second generation bio-plastics and biofuels, and as surfactants. This review examines the results of a retrospective and prospective study in polymer technology of the latent properties inherent in rubber seed shell with particular emphasis on its utilization in polymer technology.

Mangrove wood particle (MP) of size range 500–1000 microns was thermally modified under inert condition to avoid oxidation at 120 °C. The untreated and treated mangrove were compounded with high-density polyethylene (HDPE) at 10 wt%, 20 wt% and 30 wt% in an extruder with twin screw and injection-moulded into rectangular bar shapes for impact tests; fractured surfaces of impact specimens were examined. Also, the differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were evaluated. The results of the impact tests showed that increase in fibre loadings gave rise to an increase in peak load and critical stress intensity factor while energy to failure and critical strain energy release rate decreased which signifies improvements in the toughness of the composites. Scanning electron microscopy images revealed that there is stronger adhesion between the HDPE matrix of treated MP than their untreated counterparts. A decrease in the degree of crystallinity (Xc) was noted in the DSC of all composites with treated composites showing higher values of Xc. TGA showed a slight increment in the degradation peak temperature (Tp) of treated MP and MP/HDPE composites.

The effect of Zinc Oxide level as an activator on the Mechanical properties of Natural Rubber Composite was studied. It has been discovered that technicians usually add additional Zinc oxide different from the recommended dosage used in the formulation receipt during the process of compounding and also recovery of scorched compounds. One hundred parts per hundred rubber (100phr) of Natural rubber was compounded with Zinc Oxide levels of, 0, 2, 3, 4, 5, 6, 7, 8, 10phr respectively. The effect of Zinc Oxide level on tensile strength, elongation at break, modulus, hardness, abrasion resistance and compression set were investigated. The result obtained showed that as the Zinc Oxide level increased, the tensile strength, elongation at break, modulus, hardness and compression set attained their maximum values at 5.0phr, after which there was a gradual decrease of same properties as a result of reversion. For the purpose of hardness and enhanced tensile properties, a known quantity of 5.0phr is recommended.Keywords: Activator, Composite, Mechanical properties, Natural Rubber, Zinc Oxide.

The performance of graphite oxides from waste batteries and carbonized maize cobs as filler in natural rubber was evaluated in this study. Graphite from carbon electrodes in waste batteries and carbonized maize cobs respectively were subjected to the conventional Hummers method for conversion to the more reactive graphite oxides. The oxides were characterized in terms of their surface area, ash content, pH, moisture content, conductivity and loss on ignition using standard methods. The oxides were further characterized in terms of their morphology and functional groups. The graphite oxides and N330 carbon black which acts as the control were then used as filler in natural rubber compounding using the two–roll mill and subjected to physicomechanical characterization. The graphite oxides showed significant enhancement in the reinforcement and mechanical properties of the natural rubber compounds as evidenced from the results obtained when compared with the control. Morphological study of the vulcanizates shows that natural rubber – maize cob graphite oxide (NR/MCGO) vulcanizates showed very good dispersion in the rubber matrix. Mechanical properties study shows that NR/MCGO vulcanizates are having improved properties with tensile strength of 32.79MPa, modulus at 100% elongation of 19.51MPa. However, NR/MCGO vulcanizates show lower elongation at break of 500.02%. The highest hardness value is NR/MCGO of 71.01 IRHD. Keywords : Maize cob, natural rubber, fillers, graphite oxides

AbstractThe effects of the application of the graft copolymers (Hydrolyzed starch-g-polyacrylonitrile (HSPAN) and Hydrolyzed starch-g-polyacrylic acid (HSPAA)) on the nitrogen (N) and phosphorus (P) retention capacity of soil was evaluated in this study. Soil nutrient (N and P) retention capacity tests was carried out at three graft copolymers application rates (3.0, 6.0, and 9.0g/kg soil) against a blank soil sample to which graft copolymers was not applied. Diammonium phosphate (DAP) at 0, 100, and 200mg in aqueous solution/kg soil were applied in triplicates. The soil samples were mixed thoroughly and allowed to air-dry. The residual N and P contents of the soil samples were determined and reported as the amounts of nutrients retained as a function of the graft copolymer and DAP application rates. The result of this study has clearly demonstrated the potential of the graft copolymers to alleviate problems related to nutrient loss from the soil media. Leaching of nutrients (N and P) in soil has been found to be reduced to minimal (0.46%N, and 1.13%P) with the application of hydrolyzed graft copolymer and the nutrients are thus available to plant for growth by suction pressure difference.

The effect of carbonization on the processing characteristics of rubber seed shell powder was studied. Rubber seed shells were carbonized at different temperatures and then ground into fine powder. The various powders obtained were then characterized by pH, bulk density, moisture content, iodine adsorption value, yield%, conductivity and loss on ignition. The results show that there was a significant change in the pH as the heating temperature increases. The bulk density and moisture content decrease with increasing heating temperature while the iodine adsorption number and the loss on ignition increase with increasing heating temperature thus showing that carbonization has a significant influence on the processing characteristics of rubber seed shell.

The extent of biodegradation of polyurethane foams produced using the sugar bagasse from native sugar cane plant as a source for natural cellulose fibers for the production of cellulose based biodegradable polyurethane foams was explored in this study. Cellulose microfibers from sugar bagasse were isolated. The chemical and surface morphological structures of the isolated cellulose were characterized with FTIR, SEM, and Lignin content determination. Polyurethane foams were made from polyols containing as much as 25 ml liquid cellulose. The extent of biodegradability of the foams were evaluated using short-term accelerated laboratory experiments including microbial analysis, and soil burial experiments, to determine the integrity of the foams in the soil. The experimental results have shown that the foams studied biodegraded under anaerobic conditions. Weight loss and change in the tensile strength of the foams after biological exposure were observed. The composition of the foams and the liquid cellulose used in this study could have played a significant role in its yield to microbial attack during the biodegradation experiments.

Hydrolyzed starch graft poly (acrylic acid) and starch graft poly(acrylonitrile) copolymers were used as a sorbents for the removal of Pb(II) from aqueous solution in batch process. The sorbents were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy and thermogravimetric analysis. The effect of contact time, initial concentration and temperature were assessed to optimize the conditions for maximum sorption of the metal ions. The experimental data were analyzed by Langmuir, Freundlich, Temkin, Dubinin Radushkevich and Sips isotherm models. The Freundlich and the Sips isotherms confirmed the applicability of the models. The sorption capacity of the sorbent was found to be 118.61 mg/g for starch graft poly (acrylic) acid and 115.83 mg/g for starch graft poly (acrylonitrile). The Sorption kinetics was assessed by Lagergren pseudo first order, pseudo second order, Elovich equation, Intraparticle diffusion and the liquid film diffusion models. The experimental data fitted very well with the Elovich equation and the Intraparticle kinetic models. The thermodynamic analysis showed that the sorption was a spontaneous and endothermic process. The results indicated that starch graft copolymers can be used as an effective sorbents for Pb (II) removal from aqueous media.

The competitive sorption of Cu (II), Pb (II) and Cd (II) by graft copolymer of cassava starch and acrylic acid was investigated using the response surface methodology. Optimization of the medium conditions was studied through experimental design. Response surface methodology including central composite design was successfully applied to develop a response surface to optimize the medium conditions. The most influential medium parameters were determined as initial concentration, contact time and temperature. The optimum conditions were evaluated to be 41.89 mg/l, 5.66 h, and 26.11°C, for all the ions in solution, representing the initial concentration, contact time, and temperature. At these optimum conditions, the sorption yield, sorption capacity and the coefficient of determination were evaluated as follows: for Cu (II) ions 92.05 %, 38.56 mg/l and 0.963 mg/lrespectively, for Pb (II) 66.60 %, 27.9 mg/l, and 0.941 and for Cd (II) 42.90%, 17.97 mg/l and 0.904 respectively. The sorption affinity for the metals follow the order Pb > Cu > Cd, this order suggests that electronegativity may be the most important factor as metal sorption increased with increasing electronegativity. Pb2+ sorption on the graft copolymer was competitively higher than Cd (II) and Cu (II).

Research has shown that the carbon content of wastes decreases during composting with an increase in the nitrogen content. This indicates that the increased microbial activity in the process results in an increased mineralisation rate of organic nitrogen. A formula containing biochar in the form of terra preta, biochar bokashi, biochar glomalin, biochar hydrogel and biochar mokusaku-eki could further enhance the stability of the system and its effectiveness as a soil ameliorant. It could increase the cation exchange capacity, reuse crop residue, reduce runoff, reduce watering, reduce the quantity of fertiliser, increase crop yield, build and multiply soil biodiversity, strengthen and rebuild our soil food web, sequester atmospheric carbon in a carbon negative process, increase soil pH, restructure poor soils, and reduce carbon dioxide/methane/nitrous oxide/ammonia emissions from gardens and fields. This paper considers these claims and also the wider environmental implications of the adoption of these processes. The intention of this overview is not just to summarise current knowledge of the subject, but also to identify gaps in knowledge that require further research.

Melon seed shell was de-shelled, broken down into smaller pieces and then hydrolyzed with 10%(w/w) of nitric acid; oven-dried at 960c for 30mins and then bleached with sodium hypochlorite with 10% chlorine for 24hrs and washed with distilled water and dried. The dried chemically modified melon peel (CMF) were ground using a local mill and sieved to get a fine dispersion of dried melon peel filler and a higher dispersion in the adhesive. The powdered melon seed shell and CMF are chemically analyzed using standard methods. The adhesive was prepared using poly (vinyl alcohol) as reinforcing additive; it was characterized and modified using cellulose microfiber from melon seed shell. The result of the CMF modified fiber adhesive in terms of bond strength, and peel strength revealed that melon seed shell can favorably be used as filler in adhesive manufacturing and also reduce environment waste. The result of the parameters studied before and after treatment of the adhesive show that cellulose microfiber melon seed shell is effective as filler in adhesive production.

The conventional methods for treating wastewaters are expensive. Consequently, the use of agricultural waste byproduct as adsorbents for this purpose is being exploited because of its availability and low cost of the materials. Dika-nut seed shell was collected form Igueben Local Government Area of Edo State, air-dried and activated with 50% saturated ammonium chloride solution before carbonizining in a muffle furnace at 500°C. The powdered activated carbon obtained was characterized in terms of pH, bulk density, surface area, negative surface charge, moisture content, volatile matter content and ash content. The result of the powdered activated carbon characterization is pH 4.15, bulk density, 0.689g/cm3, surface area, 1.4 x 10-2g/mgI2 negative surface charge, 2.240mmol/H+, moisture content, 5.770% volatile matter, 75.10%, Ash content, 24.90%. Waste water was collected from saloon and characterized for its pollution characteristics. Turbidity, 997.33FTU, PH, 8.31, conductivity; 711us, Total suspended solid, 12600mg/l, Total Dissolved solid 355.50 mg/l. Percent Nitrogen 1.16%, nitrate Nitrogen, 76.85ppm, Nitrite Nitrogen 6.50ppm, Ammonium Nitrogen 842.85ppm, sulphate 677.98ppm, phosphate 20.09ppm, Chemical Oxygen Demand (COD) 1120.00mg/l. Dissolved oxygen 5.45 mg/l, Biological Oxygen Demand (BOD) 2.34mg/l, Pb, 31.68ppm, Zn, 1.85ppm, Cd, 0.93 ppm. Total Aerobic count 1.724107 /100ml and total coli form count 1.22x107 (fus/ml). These values are high when compared with Federal Environmental Protection Agency (FEPA) effluent discharged standard and on treatment with the powdered carbon, the following percentage reductions were obtained. Turbidity between 94.18%-96.42%, pH, 18.7-18.299, conductivity, 10.41%, TSS, 99.21-99.60%, TDS, 10.41%, Nitrite Nitrogen, 99.73%, Ammonium nitrogen 77.85-82.87%, Sulphate 79.41-88.60%, phosphate, 52.02-97.76%, COD, 60.71%, DO, 56.88-68.99%, BOD, 47.01-57.26% Pb, 25.41-60.70%, Zn, 20-57.84%,. This results show that powdered activated carbon from agricultural residue is efficient in the treatment of waste waster such as saloon effluent.