Optimization of biodiesel production from waste cooking oil using ion-exchange resins

Waste cooking oil is a potential substitution of refined vegetable oil for the production of biodiesel due to the low cost of raw material and for solving their disposal problem. In this study, optimization of esterification process of free fatty acids in artificially acidified soybean oil with oleic acid has been carried out using methanol as an agent and ion exchange resin as a heterogeneous catalyst. The esterification reaction has been investigated based on the mass balance of the developed model. The model has been validated against experimental data and effects of temperature and catalyst weight have been analyzed. Thereafter, optimization process has been fulfilled for two different objective functions as conversion of acid oil and benefit. Optimization results indicated that the maximum conversion of acid is 95.95%, which is achievable at 4.48-g catalyst loading and reaction temperature of 120°C. Maximum benefit was obtained as US$0.057 per batch of reaction at a catalyst amount of 1 g and temperature of 120°C.     

Water and waste load allocation in rivers with emphasis on agricultural return flows: application of fractional factorial analysis

In this paper, a new methodology is developed to handle parameter and input uncertainties in water and waste load allocation (WWLA) in rivers by using factorial interval optimization and the Soil, Water, Atmosphere, and Plant (SWAP) simulation model. A fractional factorial analysis is utilized to provide detailed effects of uncertain parameters and their interaction on the optimization model outputs. The number of required optimizations in a fractional factorial analysis can be much less than a complete sensitivity analysis. The most important uncertain inputs and parameters can be also selected using a fractional factorial analysis. The uncertainty of the selected inputs and parameters should be incorporated real time water and waste load allocation. The proposed methodology utilizes the SWAP simulation model to estimate the quantity and quality of each agricultural return flow based on the allocated water quantity and quality. In order to control the pollution loads of agricultural dischargers, it is assumed that a part of their return flows can be diverted to evaporation ponds. Results of applying the methodology to the Dez River system in the southwestern part of Iran show its effectiveness and applicability for simultaneous water and waste load allocation in rivers. It is shown that in our case study, the number of required optimizations in the fractional factorial analysis can be reduced from 64 to 16. Analysis of the interactive effects of uncertainties indicates that in a low flow condition, the upstream water quality would have a significant effect on the total benefit of the system.     

Contaminants of emerging concern: a review of new approach in AOP technologies

The presence of contaminants of emerging concern (CECs) such as pharmaceuticals and personal care products (PPCPs), endocrine-disrupting compounds (EDCs), flame retardants (FRs), pesticides, and artificial sweeteners (ASWs) in the aquatic environments remains a major challenge to the environment and human health. In this review, the classification and occurrence of emerging contaminants in aquatic environments were discussed in detail. It is well documented that CECs are susceptible to poor removal during the conventional wastewater treatment plants, which introduce them back to the environment ranging from nanogram per liter (e.g., carbamazepine) up to milligram per liter (e.g., acesulfame) concentration level. Meanwhile, a deep insight into the application of advanced oxidation processes (AOPs) on mitigation of the CECs from aquatic environment was presented. In this regard, the utilization of various treatment technologies based on AOPs including ozonation, Fenton processes, sonochemical, and TiO₂ heterogeneous photocatalysis was reviewed. Additionally, some innovations (e.g., visible light heterogeneous photocatalysis, electro-Fenton) concerning the AOPs and the combined utilization of AOPs (e.g., sono-Fenton) were documented.     

Report: The assessment of hospital waste management:a case study in Tehran

Hospital waste management is an important process that must be dealt with diligently. The management of hazardous waste material requires specific knowledge and regulations and it must be carried out by specialists in the field. In this cross-sectional study, we assessed the main stages of hospital waste management including separation, containment, removal and disposal of waste materials in public hospitals affiliated with Tehran University of Medical Sciences (TUMS). We selected 108 units of six hospitals (three general hospitals and three subspecialty hospitals) from those hospitals supervised by TUMS using the cluster sampling method. The measurement was conducted through a questionnaire and direct observation by researchers. Association analysis was done by statistical tests; Fisher exact test and chi-squared using SPSS software. According to the results obtained by the questionnaire, most of the studied wards scored moderately in terms of quality of their performance in all stages of waste management. About one-fifth of the wards were suffering from poor management of their medical waste and only a minority of wards obtained good scores for managing their waste materials. The findings also revealed significant associations between temporary waste storage and collection and the level of education of the managers (P = 0.040, P = 0.050, respectively). In summary, the study indicated a moderate management in all processes of separation, collection, containment, removal and disposal of waste materials in hospitals with several observed problems in the process.     

Extraction of Lignosulfonate from Black Liquor into Construction of a Magnetic Lignosulfonate-Based Adsorbent and Its Adsorption Properties for Dyes from Aqueous Solutions

Journal of Polymers and the Environment - Lignosulfonate, one of the lignin derivatives, was extracted from the black liquor as a byproduct of the wood and paper industry. It was used to prepare...     

Investigation of simultaneous multiple UV filters degradation efficiency of plasmonic Ag@AgCl photocatalyst in the aquatic environment under sunlight irradiation

Environmental Science and Pollution Research - UV filters as an important class of emerging organic pollutants are continuously released into and transported between the aquatic environments. So,...     

Importance of timely metadata curation to the global surveillance of genetic diversity

Genetic diversity within species represents a fundamental yet underappreciated level of biodiversity. Because genetic diversity can indicate species resilience to changing climate, its measurement is relevant to many national and global conservation policy targets. Many studies produce large amounts of genome-scale genetic diversity data for wild populations, but most (87%) do not include the associated spatial and temporal metadata necessary for them to be reused in monitoring programs or for acknowledging the sovereignty of nations or Indigenous peoples. We undertook a distributed datathon to quantify the availability of these missing metadata and to test the hypothesis that their availability decays with time. We also worked to remediate missing metadata by extracting them from associated published papers, online repositories, and direct communication with authors. Starting with 848 candidate genomic data sets (reduced representation and whole genome) from the International Nucleotide Sequence Database Collaboration, we determined that 561 contained mostly samples from wild populations. We successfully restored spatiotemporal metadata for 78% of these 561 data sets (n = 440 data sets with data on 45,105 individuals from 762 species in 17 phyla). Examining papers and online repositories was much more fruitful than contacting 351 authors, who replied to our email requests 45% of the time. Overall, 23% of our email queries to authors unearthed useful metadata. The probability of retrieving spatiotemporal metadata declined significantly as age of the data set increased. There was a 13.5% yearly decrease in metadata associated with published papers or online repositories and up to a 22% yearly decrease in metadata that were only available from authors. This rapid decay in metadata availability, mirrored in studies of other types of biological data, should motivate swift updates to data-sharing policies and researcher practices to ensure that the valuable context provided by metadata is not lost to conservation science forever.     

DRASTIC framework improvement using Stepwise Weight Assessment Ratio Analysis (SWARA) and combination of Genetic Algorithm and Entropy

Environmental Science and Pollution Research - Hybrid and integrated techniques can be used to investigate intrinsic uncertainties of the overlay and index groundwater vulnerability assessment...     

Determination of 2,4-Dichlorophenoxyacetic acid in food and water samples using a modified graphene oxide sorbent and high-performance liquid chromatography

Abstract

In the present work, dispersive micro-solid phase extraction (D-μ-SPE) method using magnetic graphene oxide tert-butylamine (GO/Fe₃O₄/TBA) nanocomposite, as an efficient sorbent, was applied for determining 2,4-dichlorophenoxyacetic acid (2,4-D) in water and food samples. Detection was carried out using high-performance liquid chromatography (HPLC) instrument. Influential parameters of D-μ-SPE such as sorbent and its amount, elution solvent and its volume, adsorption and desorption times and pH of sample solution were investigated and optimized. Under the optimized conditions, limit of detection and quantitation values were 0.007 and 0.02?μg/mL, respectively. Recovery data for several real samples were obtained within the range of 88.0–94.0% with a relative standard deviation (RSD) less than 7.5%. The proposed method was successfully applied to quantitative determination of 2,4-D in several vegetables and water samples.