The diminishing reserves and environmental consequences of the fossil fuel-based petrodiesel necessitate the exploration of an alternative fuel with better quality and minimum environmental impacts. The study explores the optimization of biodiesel production from nonfood and locally available mixed feedstocks as an effective and a sustainable approach to solve the insufficiency and high costs of single oil feedstock. The selection of suitable oil feedstocks and optimization of process variables are the prime issues for cost-effective industrial scale production of biodiesel from mixed feedstocks toward the industrial scale production of biodiesel. The objective of this study was to optimize process variables for the alkaline transesterification of mixed castor seed and microalgae oils to optimize the yield of biodiesel. Oils were extracted from dried microalgae (Chlorella vulgaris) biomass and castor seed kernel using methanol. The oils were purified, characterized, mixed in a 1 : 1 ratio, and converted to biodiesel. The transesterification experiments designed according to the central composite design (CCD) were used to optimize the yield of biodiesel through the response surface methodology (RSM). Experimental results were analyzed by response surface regression to produce a model for predicting biodiesel yield. Model significance, fitness, the effect of significant variables, and interactions between the variables on the yield of biodiesel were studied through the analysis of variance (ANOVA). The optimization of transesterification process variables revealed that the catalyst concentration of 1.23% (w/w), ethanol to mixed oil ratio of 5.94 : 1 (v/v), and reaction temperature of 51.0°C were the optimum conditions to achieve an optimum biodiesel yield of 92.88%. Validation experiments conducted under the optimum conditions resulted in the biodiesel yield of 92.36%, which is very close to the model predicted value. Various standard methods were used to characterize the biodiesel produced under optimum conditions, and it was found compatible with ASTM 751 and EN14214 biodiesel standards.
Stringent discharge limits, high costs, and low removal efficiency of the conventional treatment methods are facing challenges to handle industrial effluents containing heavy metals. The objective of this study was to use a recoverable magnetic zeolite to remove Cr(VI) from aqueous solution. The study investigated the application of nanotechnology to improve surface properties, recoverability, and adsorptive capacity of natural zeolite and the CCD-RSM-based optimization of adsorption process variables. Natural zeolites coated with various fractions of magnetic nanoparticles (25%, 33.33%, 50%, and 75%) were investigated for surface characters, adsorption capacity, removal efficiency, and recoverability. Natural zeolite coated with 33.33% (MZ33) was found a better adsorbent in terms of surface characters, adsorption capacity, and removal efficiency. Thirty batch adsorption experiments designed with CCD were carried out in order to optimize adsorption process variables using response surface methodology (RSM). It was found that
adsorbent
dose
=
2
g
/
L
,
contact
time
=
75
min
,
initial
Cr
VI
concentration
=
10
mg
/
L
, and
solution
pH
=
1.5
were the optimum conditions to achieve 93.57% Cr(VI) removal, which is very close to the experimental result of 94.88%. The adsorption isotherm determined from the operating parameters revealed that experimental data fit to the Langmuir isotherm model with
R
2
=
0.9966
and
maximum
adsorption
capacity
=
43.933
mg
/
g
. This proved that the adsorption of Cr(VI) on magnetic zeolite involved monolayer adsorption on the active sites. The separation factor,
R
L
, value lies between 0 and 1 indicating that adsorption of Cr(VI) on the magnetic zeolite is favorable. The adsorption kinetics study follows pseudo-first order in the removal of Cr(VI). FTIR analysis of magnetic zeolite revealed the presence of numerous functional groups participating in Cr(VI) adsorption. The current study confirmed that magnetic zeolite is a cost-effective and favorable material for the removal of Cr(VI) from aqueous solution.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.