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Fluoride levels in seven commercial phosphate fertilizers (four single superphosphate samples, two diammonium phosphate samples, and one ammonium nitrophosphate sample) were analyzed independently at three laboratories employing the techniques of ion chromatography and ion-selective electrode. The results were consistent for aqueous solutions containing 100 mg L−1 (ppm) of fertilizer. The average values of fluoride from four different studies varied from 0.140 ± 0.006–1.33 ± 0.158% (w/w) for the seven fertilizer samples. The [P2O5]/[F] ratios (w/w) were computed for all the seven samples and the values were in the range of 13.79–328.57. By comparing these values with the average [P2O5]/[F] ratio in phosphate rock, it was inferred that 3–75% of fluoride originally present in rock remained in the fertilizers. IR spectral data revealed a small peak at 716 cm−1 – indicative of SiF62− – in the sample containing lowest fluoride which may be on account of fluoride stripping of intermediate phosphoric acid with reactive silica in this case. Considering 15 MMT (million metric tons) of annual consumption of phosphate fertilizers in India, the incremental load of fluoride in agricultural fields was estimated to be 127,650 ± 14,550 MTy−1 based on the grand average fluoride content of 0.851 ± 0.097% (w/w). While a part of this fluoride would likely get discharged into oceans through run-off, the remainder may persist in the soil, some amount may accumulate in vegetation, and a part might find its way into fresh water bodies, thereby aggravating the fluoride problem in the Country. The problem of non-point source pollution can be reduced by eliminating fluoride at source, and utilizing the recovered fluoride as feedstock. This could, in principle, satisfy the entire requirement of the fluorochemicals industry in India. Environmental costs need to be factored in while making an assessment of the viability of fluoride recovery and reuse in this manner compared to production from virgin sources of fluoride.

An improved approach based on the use of iron-doped polymeric beads (IPB) as Fenton catalyst in the pretreatment and biomass-doped polymeric bead (BPB) in the biological oxidation has been reported for the removal of different aromatic mixtures present as pollutants in the aqueous solutions. Degradation has been investigated at fixed loading of IPB as 2.5 % weight basis and varying loading of hydrogen peroxide so as to understand the effect of oxidant loading on the extent of degradation. It has been observed that the maximum removal efficiency as 75.5, 81.4, and 59.1 % was obtained for the benzene-toluene-naphthalene-xylene (BTNX), benzene-toluene-ethylbenzene-xylene (BTEX), and benzene-toluene-naphthalene-p-nitrophenol (BTNp-NP) mixtures, respectively, at a 40-min pretreatment and optimum pH of 3.5. The biodegradability index was also observed in the favorable range of 0.4 to 0.5 after the pretreatment at optimum H2O2 loading of 1.5 g L−1. Maximum COD removal efficiency of 99.2, 99.3, and 99.6 % was obtained using the biological oxidation treatment for 40 h for the case of BTNX, BTEX, and BTNp-NP mixtures, respectively. Analysis of kinetic models revealed that degradation followed three distinct stages based on fitting of the three-stage model and BPB was found to be more efficient as compared to the primary activated sludge (PAS) and modified activated sludge (MAS). Reusability studies confirmed that both IPB and BPB were effective over many cycles giving stable performance during degradation without leaching of Fe3+ ions into the solution.

It was reported by us in 2018 that phosphate fertilizers marketed in India are contaminated with fluoride (0.85 % w/w on average). A follow-up study conducted in 2019 did not reveal any improvement in the situation. It is reported herein that 57–89 % w/w residual fluoride in as-received single superphosphate (SSP) powder samples could be removed through thermal treatment at 140 ± 5 °C. Fluoride removal was ascribed to formation and escape of gaseous acidic fluoride constituents, with concomitant increase in the fertilizer pH from 4.7-5.8 to 6.0–6.5. The pH increase was likely due to a shift of the H 2 P O 4 - ⇌ H P O 4 2 - equilibrium to the right. A marginal reduction in the sample mass (4.2–10.2 % w/w) was also observed. Similar thermal treatment given to as-received granular diammonium phosphate (DAP) samples reduced the fluoride content by 57–93 % w/w. The reduction was ascribed to removal of ( N H 4 ) 2 S i F 6 , which has lower decomposition temperature than DAP. The pH of the DAP samples reduced from 8.2–8.5 to 6.5–7.7, the sample mass reduced by 7.4–16.6 % w/w, and in one sample subjected to N, P analysis, the N/P ratio reduced from 1.16 to 0.71. These observations were consistent with a partial loss of ammonia and a shift of the H P O 4 2 - ⇌ H 2 P O 4 - equilibrium to the right. Exposure of a heat-treated DAP fertilizer to ammonia vapour raised the pH to 8.1. This suggested that, if fluoride impurities can be separated out from the gaseous emission released on thermal treatment, the lost ammonia can, in principle, be recycled to regenerate the original DAP through gas-solid reaction.

Fenton oxidation and ultrasound-based pretreatment have been applied to improve the treatment of real industrial wastewater based on the use of biological oxidation. The effect of operating parameters such as Fe(2+) loading, contact time, initial pH, and hydrogen peroxide loading on the extent of chemical oxygen demand (COD) reduction and change in biochemical oxygen demand (BOD5)/COD ratio has been investigated. The optimum operating conditions established for the pretreatment were initial pH of 3.0, Fe(2+) loading of 2.0, and 2.5 g L(-1) for the US/Fenton/stirring and Fenton approach, respectively, and temperature of 25 °C with initial H2O2 loading of 1.5 g L(-1). The use of pretreatment resulted in a significant increase in the BOD5/COD ratio confirming the production of easily digestible intermediates. The effect of the type of sludge in the aerobic biodegradation was also investigated based on the use of primary activated sludge (PAS), modified activated sludge (MAS), and activated sludge (AS). Enhanced removal of the pollutants as well as higher biomass yield was observed for MAS as compared to PAS and AS. The use of US/Fenton/stirring pretreatment under the optimized conditions followed by biological oxidation using MAS resulted in maximum COD removal at 97.9 %. The required hydraulic retention time for the combined oxidation system was also significantly lower as compared to only biological oxidation operation. Kinetic studies revealed that the reduction in the COD followed a first-order kinetic model for advanced oxidation and pseudo first-order model for biodegradation. The study clearly established the utility of the combined technology for the effective treatment of real industrial wastewater.

Improved biological oxidation based on pretreatment using combined Fenton and ultrasound in presence of stirring as the best approach and use of modified activated sludge was demonstrated for the treatment of wastewater containing benzene, toluene, naphthalene and o-xylene. The optimum pretreatment conditions were observed as initial pH of 3–3.5, Fe 2+ dosage of 2.0 g L –1 and H 2 O 2 dosage of 1.0 g L –1 giving about 80–95% reduction in the chemical oxygen demand (COD) and favorable BOD 5 /COD value for the biological oxidation. Use of modified prepared activated sludge gave about 20–30% higher extent of degradation as compared to the conventional sludge types.

The treatment of a synthetically prepared wastewater containing ethylbenzene and p-nitrophenol has been investigated using combined treatment schemes based on the advanced oxidation process followed by the conventional aerobic oxidation process (using primary activated sludge (PAS), modified prepared activated sludge (MPAS) based on the use of combined sludge from different treatment sources and activated sludge (AS)). The operating conditions for the pretreatment scheme have been optimized and it has been observed that initial pH of 3–3.5, a Fe2+ dosage of 2.0 g L−1 and a H2O2 dosage of 1.5 g L−1 in combination with ultrasound gives the best performance. Approximately, 55–70% reduction in the chemical oxygen demand (COD) was obtained at optimum conditions after pretreatment from initial conditions of COD as 3642 and 3417 mg L−1 and BOD as 881 and 533 mg L−1 for the wastewater containing ethylbenzene and p-nitrophenol respectively. From an initial BOD5/COD (BI) value of around 0.15–0.2, the ratio was found to increase to about 0.30–0.35 after pretreatment, which is considered good for the aerobic treatment. In the case of aerobic oxidation, promising results were obtained for the modified prepared activated sludge giving better conversion ability of intermediates into solid residue and higher biomass yield that could be separated by simple filtration as compared to the primary activated or the activated sludge treatment. The best treatment approach as established in the work was ultrasound assisted Fenton process as the pretreatment followed by biological oxidation using MPAS.

The present work reports the preparation of modified activated sludge (MAS) with isolation studies and performance evaluation for the removal of aromatic pollutants. On the basis of biochemical and physiological characteristics study, about 389 bacterial isolates (combination of gram-negative and gram-positive) were identified in the sludge. Performance evaluation studies for treatment of wastewater containing aromatic pollutants using modified activated sludge revealed that a maximum of 67% reduction in the pollutant loading was obtained for only biological process which significantly increased to 98% for the combined process of Fenton treatment and biological oxidation. Improved biodegradability was also observed with BOD5/COD value of about 0.30–0.35 with pretreatment time of 40 min for effluent containing benzene, toluene, naphthalene and xylene and 60 min for effluent containing ethylbenzene and p-nitrophenol. Comparison of the performance of MAS with the more commonly used prepared activated sludge and the activated sludge process revealed superior degradation effectiveness and growth characteristics. Kinetic studies also revealed that maximum substrate reduction with enhanced microbial growth of bacterial strain was obtained for MAS. Overall the present work has clearly highlighted the novelty of using a modified activated sludge based on the mixed culture of microorganisms and the better efficacy of the combined treatment scheme based on Fenton’s oxidation and biological oxidation using MAS.

BACKGROUND Improvements in biological oxidation approaches are required due to significant problems associated with this simple and commonly used approach. The work presents use of immobilized modified prepared activated sludge using modified polyvinyl alcohol (PVA)-alginate beads for removal of BTX and modifications based on the use of Fenton chemistry as pretreatment scheme. RESULTS Improved synthesis processes for immobilized sludge beads have been developed based on understanding the effect of PVA and alginate loadings. Stable beads with high levels of sludge activity were shown to give similar levels of COD removal efficiency compared with free sludge. In the case of Fenton pretreatment, 40 min of treatment was found to increase BOD5:COD value to about 0.31. Maximum COD efficiency of 93.1% was obtained using a biological process on a Fenton-treated sample which is significantly higher than that obtained with the untreated sample. The immobilized sludge was reused over nine batches without substantial loss in BTX degradation ability. Kinetic studies have also been presented. CONCLUSION An improved and promising approach for treatment of BTX containing wastewater with proven efficacy of the bioactivity and mechanical stability of the immobilized sludge, has been presented with better results based on Fenton pretreatment. © 2014 Society of Chemical Industry

Molecular diagnostics has changed the way lung cancer patients are treated worldwide. Of several different testing methods available, PCR followed by directed sequencing and amplification refractory mutation system (ARMS) are the two most commonly used diagnostic methods worldwide to detect mutations at KRAS exon 2 and EGFR kinase domain exons 18-21 in lung cancer. Compared to ARMS, the PCR followed by directed sequencing approach is relatively inexpensive but more cumbersome to perform. Moreover, with a limiting amount of genomic DNA from clinical formalin-fixed, paraffin-embedded (FFPE) specimens or fine biopsies of lung tumors, multiple rounds of PCR and sequencing reactions often get challenging. Here, we report a novel and cost-effective single multiplex-PCR based method, CRE (for Co-amplification of five KRAS and EGFR exons), followed by concatenation of the PCR product as a single linear fragment for direct sequencing. CRE is a robust protocol that can be adapted for routine use in clinical diagnostics with reduced variability, cost and turnaround time requiring a minimal amount of template DNA extracted from FFPE or fresh frozen tumor samples. As a proof of principle, CRE is able to detect the activating EGFR L858R and T790M EGFR mutations in lung cancer cell line and primary tumors.

14-3-3 Proteins bind phosphorylated sequences in proteins and regulate multiple cellular functions. For the first time, we show that pure recombinant human 14-3-3 ζ, γ, ε and τ isofoms hydrolyze ATP with similar Km and kcat values. In sharp contrast the sigma isoform has no detectable activity. Docking studies identify two putative binding pockets in 14-3-3 zeta. Mutation of D124A in the amphipathic pocket enhances binding affinity and catalysis. Mutation of a critical Arg (R55A) at the dimer interface in zeta reduces binding and decreases catalysis. These experimental results coincide with a binding pose at the dimer interface. This newly identified function could be a moon lighting function in some of these isoforms.