threat to the environment due to their toxicological profile, nonbiodegradability, and potential for

Overview

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Key numbers

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high thermal stability (T5% = 251°C), and a high density multifunctional surface for adsorption. A key
hydroxylated triglyceride predominantly composed (~ 90%) of ricinoleic acid (C18:1–OH). This unique
(IPDI, 98%), dibutyltindilaurate (DBTL, 95% catalyst), benzoyl peroxide (BPO, 97%), and metal salts Pb(NO3)2,
Cd(NO3)2•4H2O, and K2Cr2O7 (all ≥ 99%) were purchased from Sigma-Aldrich (St. Louis, MO, USA). Sisal
facility (Egypt). These were pre-treated by sequential alkali delignification (4 wt% NaOH, 80°C, 2h) and acid
99.5%, HNO3, HCl, and NaOH of analytical grade from Fisher Scientific were the sources of the reagents.
Cr(VI) stock solution of 1000 mg/L concentration was prepared from K2Cr2O7. Solutions of Cr(VI)
ICP-OES (Agilent 5110) after suitable digestion. The concentration of Cr removal.
necked round-bottom flask under dry N2 atmosphere using DBTL catalyst (0.05 wt% based on total reactants)
prepolymer (CO-PP) as confirmed by FTIR (degradation of N = C = O absorption band at 2270 cm-1 for less than
50% conversion). Stage II: Pre treated sisal/jute fibers (1:1 mass basis; 30 wt% based on final composite) were
uniformly dispersed in CO-PP dissolved in DMSO (30 wt/vol%) by probe ultrasonic treatment (Branson 750W,
30 min, 60% amplitude, and ice bath) for uniform impregnation of fibers. Stage III: BPO (1.0 wt%) was used as a
50 mL min−1 and a heating rate of 10°C min−1 over a range of 25 to 700°C. Zeta potential and hydrodynamic
determined by ICP-OES. All batch experiments were triplicated. Error bars represent ± SD (n = 3). The adsorption
capacity qe (mg g and removal efficiency RE (%) are shown as in Eqs. 1 & 2:
considering a broader pH range for the adsorption of oxyanions. PH > 6 for Cr (VI) was not considered in the
50–2241), giving a crystallinity index (CrI) of 67.8% and 65.4% by the Segal method. Castor oil displays a
22.7° persists but with pronounced broadening (FWHM: 0.42° → 1.18°), and CrI decreases to 38.9%, reflecting
confirmed by its high thermal stability (TGA) and high surface area retention of > 93% after regeneration. Thus,
The swelling ratio of CO-BPFHC is confirmed to be 18.6%, indicating a moderate water uptake for facilitating
the diffusion of ions without affecting the structural stability of the composite (Table 1).
BET fitting range (P/Po = 0.05–0.30). The Type IV isotherm and H2(b)-type hysteresis indicate interconnected
(pHpzc = 4.6) is indicated by the dashed arrow. The pH ranges optimal for Cr(VI) (anion, pH 2.5) and Pb(II)/
CO-BPFHC. Malvern Zetasizer Nano ZS, 25°C; error bars = ± SD (n = 3).
range of 25–120°C with a 3.6% mass loss; Stage 2: Degradation of hemicellulose and fragmentation of urethane
soft segments in the range of 200–285°C with an 18.7% mass loss, as revealed by the DTG peak at 247°C; Stage
3: Simultaneous degradation of cellulose, lignin framework, and urethane hard segments in the range of 285–
420°C with a 52.4% mass loss, as revealed by the major DTG peak at 362°C; and Stage 4: Oxidative degradation
of char along with inorganic residue formation in the range of 420–600°C with an 11.2% mass loss. T5% of CO-
thermal stabilization by the Polyhydroxybutyrate encapsulation. Residual char yield at 600°C is 14.1 wt%, higher
than pure cellulose (≈7%) due to cross-linked urethane char formation.
(~ 6.5)22 and unmodified castor-oil PU (~ 5.4)23, attributable to the abundance of carboxyl groups introduced by
For Pb(II) and Cd(II), the removal efficiency increases with increasing pH from a minimum of 29.4% (Pb)
and 22.1% (Cd) at pH 2.0 to reach a maximum plateau at 96.8% and 94.2%, respectively, at pH 5.5 and 6.0.
efficiency occurs at a pH of 2.0–2.5 (RE = 95.4% at pH 2.5), gradually decreasing to a pH of 7.0 at 41.2%. This
to 0.5 g L−1: Pb(II) from 58.4 to 96.8%; Cd(II) from 44.7 to 94.2%; and Cr(VI) from 67.1 to 95.4%. The higher
RE, i.e., up to 97–99%, but with a significant reduction in unit adsorption capacity, from its maximum at 0.1 g L−1
annotated. T5% = 251°C for CO-BPFHC vs. 191°C (sisal) and 178°C (jute). Netzsch STA 449F3 simultaneous
rapid uptake phase at the beginning of the experiment (0–30 min, corresponding to 63–70% of the maximum
showed a faster uptake profile at the beginning of the experiment (0–20 min, corresponding to 74% of maximum
Qmax values are 591.4 for Pb, 432.7 for Cd, and 387.6 for Cr (Table 2). The Qmax for Cr(VI) is found to be lower

Methods (brief)

ICP-OES (Agilent 5110) after suitable digestion. The concentration of Cr removal.
on a JEOL JSM-7610F (10 kV; Au-coated samples). TEM and HRTEM images were taken on a FEI Tecnai G2 F20
2020 surface area analyzer. Prior to analysis, samples were degassed under vacuum at 150°C for 12 h to remove
effects. Only one parameter was varied at a time. Pb(II) and Cd(II) were quantified by ICP-OES after filtration
determined by ICP-OES. All batch experiments were triplicated. Error bars represent ± SD (n = 3). The adsorption
The samples were extracted after 0, 5, 10, 15, 20, 30, 45, 60, 90, 120, 180, and 240 min. Four kinetic models,
loaded CO-BPFHC samples is provided. Obvious shifts in the position and changes in the intensity of the main
N2 adsorption/desorption isotherm (Fig. 6) and BJH pore size distribution (Fig. 7) of the CO-BPFHC sample
of complex pore structure of the mesoporous material3. The BET surface area of the CO-BPFHC sample

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Update history

The five most recent substantive edits to this page, classified major (evidence or structure moved), correction (a published value or statement was wrong and has been fixed), or minor (narrative rewritten without changing the underlying evidence). Each description is derived from what the edit did to this page; the linked commit is the authoritative record, routine regeneration passes are excluded, and the full version history lives in git. When DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.

Commit	Date	Change	Description
b01ec52c	2026-08-04	major	2 sections added
d49e450f	2026-08-03	major	5 sections added; narrative text revised