Pinecone biochar for the Adsorption of chromium (VI) from wastewater: Kinetics, thermodynamics, and adsorbent regeneration.

High concentration of chromium in aquatic environments is the trigger for researchers to remediate it from wastewater environments. However, conventional water treatment methods have not been satisfactory in removing chromium from water and wastewater over the last decade. Similarly, many adsorption studies have been focused on one aspect of the treatment, but this study dealt with all aspects of adsorption packages to come up with a concrete conclusion. Therefore, this study aimed to prepare pinecone biochar (PBC) via pyrolysis and apply it for Cr(VI) removal from wastewater. The PBC was characterized using FTIR, SEM-EDX, BET surface area, pHpzc, Raman analyses, TGA, and XRD techniques. Chromium adsorption was studied under the influence of PBC dose, solution pH, initial Cr(VI) concentration, and contact time. The characteristics of PBC are illustrated by FTIR spectroscopic functional groups, XRD non-crystallite structure, SEM rough surface morphology, and high BET surface area125 m2/g, pore volume, 0.07 cm3/g, and pore size 1.4 nm. On the other hand, the maximum Cr (VI) adsorption of 69% was found at the experimental condition of pH 2, adsorbent dosage 0.25 mg/50 mL, initial Cr concentration 100 mg/L, and contact time of 120 min. Similarly, the experimental data were well-fitted with the Langmuir adsorption isotherm at R2 0.96 and the pseudo-second-order kinetics model at R2 0.99. This implies the adsorption process is mainly attributed to monolayer orientation between the adsorbent and adsorbate. In the thermodynamics study of adsorption, ΔG was found to be negative implying the adsorption process was feasible and spontaneous whereas the positive values of ΔH and ΔS indicated the adsorption process was endothermic and increasing the degree of randomness, respectively. Finally, adsorbent regeneration and reusability were successful up to three cycles. In conclusion, biochar surface modification and reusability improvements are urgently required before being applied at the pilot scale.

In search of experimental evidence on Scratch programming and students' achievements in the first-year college computing class? Consider these datasets.

This article presents datasets representing the demographics and achievements of computer science students in their first programming courses (CS1). They were collected from a research project comparing the effects of a constructionist Scratch programming and the conventional instructions on the achievements of CS1 students from selected Nigerian public colleges. The project consisted of two consecutive quasi-experiments. In both cases, we adopted a non-equivalent pretest-posttest control group design and multistage sampling. Institutions were selected following purposive sampling, and those selected were randomly assigned to the Scratch programming class (experimental) and the conventional (comparison) class. A questionnaire and pre- and post-introductory programming achievement tests were used to collect data. To strengthen the research design, we used the Coarsened Exact Matching (CEM) algorithm to create matched samples from the unmatched data obtained from both experiments. Future studies can use these data to identify the factors influencing CS1 students' performance, investigate how programming pedagogies or tools affect CS1 students' achievements in higher education, identify important trends using machine learning techniques, and address additional research ideas.

Impact of a Scratch programming intervention on student engagement in a Nigerian polytechnic first-year class: verdict from the observers.

An engaging first programming class (CS1) often inspires students' passion for computer science (CS). However, the evidence in the literature suggests that the average CS1 classes are anything but engaging for many students. The performance of CS compared to other science, technology, engineering, and mathematics (STEM) courses in international student engagement surveys seems to substantiate CS1 failure, attrition rates, and lack of diversity in most CS classes. Meanwhile, for its simplicity in introducing programming to beginners, primary and secondary schools use Scratch, an educational programming environment developed by the Massachusetts Institute of Technology, USA. For the same reason, higher institutions now include some forms of Scratch instruction in CS1. The question remains, to what extent is Scratch engaging, especially for students in higher education? This study addressed this gap by observing college computer science students exposed to a constructionist Scratch programming pedagogy. We adopted a descriptive design based on quantitative observations. To observe the class during a weekly 2-hour session, we employed five CS educators, one observer per week. Each observer, employing a 20-item observation protocol, rated the extent of affective, behavioral, and cognitive engagement of first-year CS students in a polytechnic in North Central Nigeria. Most of the students were learning to program for the first time. Analysis of the data showed a significant agreement in the ratings of the five observers for overall student engagement, although the impact was moderate. However, while agreement in their ratings for affective engagement was significant, with a large effect, there was no significant concordance in their ratings for behavioral engagement. Observers also significantly agreed in their ratings for cognitive engagement; however, the impact was moderate. These findings suggest that employing Scratch in higher education can be engaging and useful, especially for students with no prior programming experience.

Unravelling the genetic and functional diversity of dominant bacterial communities involved in manure co-composting bioremediation of complex crude oil waste sludge.

The present study aimed to characterize the bacterial community and functional diversity in co-composting microcosms of crude oil waste sludge amended with different animal manures, and to evaluate the scope for biostimulation based in situ bioremediation. Gas chromatography-mass spectrometry (GC-MS) analyses revealed enhanced attenuation (>90%) of the total polyaromatic hydrocarbons (PAHs); the manure amendments significantly enhancing (up to 30%) the degradation of high molecular weight (HMW) PAHs. Microbial community analysis showed the dominance (>99% of total sequences) of sequences affiliated to phyla Proteobacteria, Firmicutes, Actinobacteria and Bacteroidetes. The core genera enriched were related to hydrocarbon metabolism (Pseudomonas, Delftia, Methylobacterium, Dietzia, Bacillus, Propionibacterium, Bradyrhizobium, Streptomyces, Achromobacter, Microbacterium and Sphingomonas). However, manure-treated samples exhibited high number and heterogeneity of unique operational taxonomic units (OTUs) with enrichment of additional hydrocarbon-degrading bacterial taxa (Proteiniphilum, unclassified Micrococcales, unclassified Lachnospiraceae, Sphingobium and Stenotrophomonas). Thirty-three culturable hydrocarbon-degrading microbes were isolated from the co-composting microcosms and mainly classified into Burkholderia, Sanguibacter, Pseudomonas, Bacillus, Rhodococcus, Lysinibacillus, Microbacterium, Brevibacterium, Geobacillus, Micrococcus, Arthrobacter, Cellulimicrobacterium, Streptomyces Dietzia,etc,. that was additionally affirmed with the presence of catechol 2,3-dioxygenase gene. Finally, enhanced in situ degradation of total (49%), LMW (>75%) and HMW PAHs (>35%) was achieved with an enriched bacterial consortium of these microbes. Overall, these findings suggests that co-composting treatment of crude oil sludge with animal manures selects for intrinsically diverse bacterial community, that could be a driving force behind accelerated bioremediation, and can be exploited for engineered remediation processes.

Identification and characterization of PAH-degrading endophytes isolated from plants growing around a sludge dam.

This study involved the isolation of bacteria endophytes with PAH-degrading ability from plants growing around a sludge dam. A total of 19 distinct isolates that were morphologically identified were isolated from 4 species of plant with a follow-up confirmatory identification using the molecular technique. Polymerase chain reaction (PCR) of the 16S rRNA gene with specific primers (16S-27F PCR and 16S-1491R PCR) was carried out. The sequence of the PCR products was carried out, compared with similar nucleotides available in GenBank. Results of the phylogenetic analysis of the isolates indicated their belonging to 4 different clades including Proteobacteria, Actinobacteria, Cyanobacteria, and Firmicutes. These were related to the genera Bacillus, Pseudomonas, Terribacillus, Virgibacillus, Stenotrophomonas, Paenibacillus, Brevibacterium, Geobacillus, Acinetobacter. From the result, Pseudomonas demonstrated a high incidence in the plants sampled. The in-vitro degradation study and the presence of dioxygenase genes indicated that these lists of endophytes are able to use the list of PAHs tested as their source of food and energy leading to their breakdown. This means that the bacterial endophytes contributed to the remediation of petroleum hydrocarbons in planta, a situation that may have been phytotoxic to plant alone. Therefore, these bacteria endophytes could be potential organisms for enhanced phytoremediation of PAHs.

Isolation and characterisation of crude oil sludge degrading bacteria.

BACKGROUND: The use of microorganisms in remediating environmental contaminants such as crude oil sludge has become a promising technique owing to its economy and the fact it is environmentally friendly. Polycyclic aromatic hydrocarbons (PAHs), as the major components of oil sludge, are hydrophobic and recalcitrant. An important way of enhancing the rate of PAH desorption is to compost crude oil sludge by incorporating commercial surfactants, thereby making them available for microbial degradation. In this study, crude oil sludge was composted for 16 weeks during which surfactants were added in the form of a solution. RESULTS: Molecular characterisation of the 16S rRNA genes indicated that the isolates obtained on a mineral salts medium belonged to different genera, including Stenotrophmonas, Pseudomonas, Bordetella, Brucella, Bacillus, Achromobacter, Ochrobactrum, Advenella, Mycobacterium, Mesorhizobium, Klebsiella, Pusillimonas and Raoultella. The percentage degradation rates of these isolates were estimated by measuring the absorbance of the 2,6-dichlorophenol indophenol medium. Pseudomonas emerged as the top degrader with an estimated percentage degradation rate of 73.7% after 7 days of incubation at 28 °C. In addition, the presence of the catabolic gene, catechol-2,3-dioxygenase was detected in the bacteria isolates as well as in evolutionary classifications based on phylogeny. CONCLUSIONS: The bacteria isolated in this study are potential agents for the bioremediation of crude oil sludge.

cDNA sequence encoding metallothionein protein from Aegiceras corniculatum and its gene expression induced by Pb²âº and Cd²âº stresses.

Constructing various green wetland examples for mangrove wetland systems is a useful way to use natural power to remediate the polluted wetlands at intertidal zones. Metallothioneins (MT) are involved in heavy metal tolerance, homeostasis, and detoxification of intracellular metal ions in plants. In order to understand the mechanism of heavy metal uptake in Aegiceras corniculatum, we isolated its metallothionein gene and studied the MT gene expression in response to heavy metals contamination. Here, we report the isolation and characterization of MT2 genes from young stem tissues of A. corniculatum growing in the cadmium (Cd) and lead (Pb) polluted wetlands of Quanzhou Bay, southeast of China. The obtained cDNA sequence of MT is 512 bp in length, and it has an open reading frame encoding 79 amino acid residues with a molecular weight of 7.92 kDa and the theoretical isoelectric point of 4.55. The amino acids include 14 cysteine residues and 14 glycine residues. It is a non-transmembrane hydrophilic protein. Sequence and homology analysis showed the MT protein sequence shared more than 60% homology with other plant type 2 MT-like protein genes. The results suggested that the expression level of MT gene of A. corniculatum young stems induced by a certain range concentration of Cd(2+) and Pb(2+) stresses (0.2 mmol L(-1) Pb(2+), 1 mmol L(-1) Pb(2+), 0.2 mmol L(-1) Pb(2+), and 40 µmmol L(-1) Cd(2+); 1 mmol L(-1) Pb(2+) and 40 µmol L(-1) Cd(2+)) compared with control might show an adaptive protection. The expression levels of MT gene at 20 h stress treatment were higher than those at 480 h stress treatment. The expression levels of MT gene with 0.2 mmol L(-1) Pb(2+) stress treatment were higher than those with 0.2 mmol L(-1) Pb(2+) and 40 µmol L(-1) Cd(2+) stress treatment, and the MT gene expression levels with 1 mmol L(-1) Pb(2+) treatment were higher than those with 1 mmol L(-1) Pb(2+) and 40 µmol L(-1) Cd(2+) treatment. There exists an antagonistic action between Pb(2+) and Cd(2+) in the MT metabolization of A. corniculatum.