EQA - International Journal of Environmental Quality

Optmisation of cadmium (II) removal onto biodegradable composite using artificial neural networks and response surface methodology: quantum chemical performance

2023-12-06T17:53:51+01:00

A multifunctional grafted cellulose nanocrystals derivative adsorbent (composites) with carboxyl, amide, and secondary amino groups was successfully developed for Cd²⁺ removal. The characteristics of CNCs, chitosan, and nanocomposites were determined using FTIR, TGA, SEM, and BET. The approaches of artificial intelligence and Response Surface Methodology modeling were employed, as well as how well they predicted response (adsorption capacity). The adsorption isotherm and kinetic models were applied to comprehend the process further. Statistical results demonstrated that The response surface model approach performed better than the artificial neural network model approach. The adsorption capacity was 440.01 mg/g with a starting pH of 5.65, a duration of contact of 315 minutes, a starting concentration of 333 mg/L, and an adsorbent dose of 16.93 mg. The FTIR examination revealed that the functional groups of the nanocomposites were equivalent to those of CNCs and chitosan; however, the nanocomposites were more thermally stable than CNCs and chitosan. The nanocomposites' SEM pictures revealed a porous structure, thin particle size, and needle-like shape. The Langmuir model explains the spontaneous nature of the adsorption process, and chemisorption served as the primary control. According to the Dubinin-Radushkevich Model, to adsorb Cd^2+, the energy required is larger than 8 kJ mol-1, suggesting that the chemisorption mechanism was involved. The adsorption kinetics were established using the pseudo-second-order rate model. H_OMO−L_UMO energy binding differences were used to find the best locations for adsorption.

Photocatalytic degradation of Congo red using doped zinc oxide nanoparticles

2023-12-21T12:27:36+01:00

The photocatalytic degradation of Congo Red (CR) was studied using zinc oxide (ZnO) nanoparticles as catalyst (ZC, NZ, AZ and ANZ) under UV light, solar and dark. ZnO nanoparticles were synthesized by one-step liquid impregnation and each nanoparticles was calcined at 60 ^oC for 4 hours. The UV-vis spectra study assured that the band gap decreased as N and Ag doped to ZnO and hence the absorption band shifts toward the longer wavelength region (red shift). The morphological structures of as-synthesized nanomaterials were investigated by X-ray diffraction (XRD) and scanning electron microscope (SEM). The parameters studied were catalyst dosage and the pH of the reaction mixture. The degradation of the dye was found to be effective in the range; catalyst dose of 0.10, 0.20, 0.30 and 0.4 g ZnO catalyst/100 mL of dye solution, initial concentration 10 mg/L, and pH 8.11. Experimentation on different catalyst dosage of ZnO nanoparticles showed that 0.2 g ZnO catalyst/100 mL with the percentage degradation (ZC 70%, ANZ 99.7%, AZ 92.5%, NZ 85.8%) is the most suitable catalyst dosage for degrading CR under UV irradiation at 120 min of irradiation time. Photocatalytic processes were found to work better in basic condition and the best pH value was 8.0. The results showed that a percentage Congo Red degradation of 99.7% could be obtained when treating an effluent with 10 mg/L of Congo Red for 120 mins at 0.2 g ZnO catalyst/100 mL of effluent and pH 8 under UV irradiation using nitrogen doped silver co-doped zinc oxide, ANZ) both under solar and UV than (NZ) and silver- nitrogen doped zinc oxide (A), this was attributed to the lower rate of recombination of the photo-generated electrons and holes as well as its lower gap energy.

Characterization and suitability assessment of soils underlain by mica-schist for yam and cocoyam production in rainforest area Southwestern, Nigeria

2023-12-17T03:57:57+01:00

This study was conducted to assess the suitability of the soils underlain by mica-schist for sustainable production of yam and cocoyam. The study was carried out in 2014, in an area located approximately between 7^o32′ N and 7^o33′ N and longitudes 4^o32′ E and 4^o40′ E within the Teaching and Research Farm (T&R-F) of Obafemi Awolowo University (OAU), Kajola, Ile-Ife, Nigeria. Four profile pits were established, described and sampled with one at different physiographical units following the guideline for soil profile description according to FAO/UNESCO (2006) guideline. The soil samples collected were analyzed for particle size distribution, pH, total nitrogen, available phosphorus, exchangeable bases, and organic matter using standard method. Land characteristics obtained were matched with the crop requirements for yam and cocoyam to obtain the soils’ suitability classes using parametric method. The result showed that all the soils are well drained and deep. The texture of the soils ranged from sandy loam to sandy clay loam at the surface and sandy clay loam to clay at subsurface. Soil reaction ranged from highly acidic to slightly acidic (4.2 – 5.8 water and 3.8 – 5.4 pH KCl) with low to moderate amounts of organic matter (1.2% to 2.9%) and available nitrogen (0.07 – 0.2 %). Available phosphorus varied from 2.0 – 10.6 mg/kg in all the horizons in the profiles with the highest values at the surface soil horizons, an indication that soil organic matter contributes significantly to the available P in these soils. The exchangeable bases were low and the relative abundance of the exchangeable bases followed the order: Ca> Mg > Na>K at the exchangeable site. Suitability evaluation of the soils was carried out using parametric approach. The result showed that all the soil mapping units were permanently not suitable (N2) for cocoyam and yam production for actual suitability evaluation. With the appropriate fertility management, the soils of mapping unit 2 was classified as moderately suitable (S2) for yam production while soils of mapping units 1 and 3 were classified as marginally suitable (S3) for yam production. Soils of mapping unit 4 was classified as presently not suitable (N1) for yam production. After improvement for cocoyam production, soils of mapping unit 1 and 2 were classified as marginally suitable (S3) while soils of mapping units 3 and 4 were presently not suitable (N1). The soils were limited by wetness, texture, shallow depth and low fertility (N, P and K). Therefore, Combined application of organic fertilizer with guided inorganic fertilizers (N-P-K) should be encouraged for optimum productivity.

Efficiency evaluation of sewage treatment plants of Bikaner city (Rajasthan), India

2023-10-14T09:55:55+02:00

The present case study is the evaluation of the efficiency of sewage treatment plants (STP) of Bikaner city (Rajasthan), India. Bikaner city have two sewage treatment plants which cumulatively treat 52 million litre per day (12 MLD and 40 MLD) wastewater. Both STPs work on sequencing batch reactor technology. The performance of 40 MLD is conducted for 6 months duration (July to December 2022). The inlet and outlet wastewater samples are collected. Samples are analysed for pH, total suspended solids (TSS), Biological oxygen demand (BOD), phosphate and sulphate. The overall removal efficiency of STPs is in the order of TSS > BOD > Sulphate > Phosphate > pH. The results reveal that both STPs are considered efficacious. It is recommended that frequent monitoring and assessment should be done for proper functioning of STP.

Indigenous and modern soil management practices and its determinant factors in Yayo district, Ilubabor zone Southwest Ethiopia

2023-09-02T21:34:14+02:00

The main objective of this study was to investigate Combination level and Role of Indigenous and Modern Soil Conservation Practices in the case of Yayo District, Ilubabor zone, southwest Ethiopia. Cross-sectional research designs with both qualitative and quantitative research approaches were employed. Two stage sampling procedures with combination of purposive and simple random sampling procedures were used to select 210 sample household heads for the study. Household survey questionnaires, key informant interview, focus group discussion and field observation were used to collect the data. Binary logistic model was used to identify determinant factors of farmers’ decision to adopt soil conservation practices. The finding of the study showed that contour plowing, farmyard manure and traditional cut-off drain were the most practiced indigenous soil conservation practices. Improved crop seed, use of chemical fertilizer and insecticide and pesticide were the major improved/modern/ soil conservation practiced performed by household of the study areas. Insubstantial level of integration between indigenous and modern soil conservation practices were another finding of the study. The result also indicated as decrease soil erosion, improve income, improve water availability, and increase crop & livestock productivity were to the major contributions of integrating indigenous and modern soil conservation practiced in the study area.. The result of binary logistic regression analysis showed as livestock ownership, distances to farm plot, access to credit services and extension services were significantly (p<0.05) affect household decisions to adopt soil conservation practices. Therefore, farmers should be adopting profitable and sustainable soil management practice and integrate indigenous with modern soil management practices.